Automatic transmission does not shift gears: reasons and solutions
Automatic transmissions have already become popular among domestic motorists, although twenty years ago no one could have thought that this would happen. As a result of many advantages, the demand for these units is constantly growing. Of course, like any other unit in a car, the automatic transmission may periodically fail or function incorrectly. In fact, there can be many problems with the unit, but if the automatic transmission does not switch speeds, then the only way out is diagnostics.
But, first of all, you need to reliably make sure that this malfunction is really related to the operation of the unit. You must be sure that all systems in the vehicle are functioning properly if gear changes are not possible. In principle, one of the main malfunctions due to which the automatic transmission does not change gears is often a lack of working fluid in the system. As a rule, this is usually due to a worn out oil seal of the unit, which is why the fluid leaves the automatic transmission.
Lack of lubricant level in the box may be due to the following factors:
- Fluid leaking. Oil can come out through the crankshaft oil seals, BC gasket, oil filter seal or through oil baffle caps. If transmission oil (hereinafter referred to as TM) leaves through the oil seals, this indicates their wear, which may be caused by the use of chemicals or poor-quality lubricants. The cylinder block gasket could be worn out due to overheating of the engine or improper tightening of the screws during disassembly and assembly of the engine. If the problem is in the oil filter, then it is most likely due to the fact that the sealing gum cannot hold in place. If the oil flows out of the automatic box due to the baffle caps, then the problem is their wear caused by overheating.
- Breakdown of the vacuum corrector. Inside this device there is a special membrane that reacts to the level of vacuum in the collector. If the integrity of this element is violated, then the TM will get into the car’s motor. In this case, the unit can function for a long time even with a significantly reduced level of lubrication, but over time it will simply fail.
- If TM goes into the cooling system. If the tightness of the oil cooler is broken, then the lubricant will go to the engine radiator, since the TM pressure in the automatic transmission radiator is always higher than the pressure in the cooling system. And when the engine turns off, the process of lubricant leakage into the coolant begins. As a result, an emulsion begins to appear both in the internal combustion engine and in the automatic transmission. When antifreeze enters the automatic transmission, it corrodes the clutches, as a result of which corrosion begins to form on the latter. In the event that the gears do not shift not so long ago, then the malfunction can be solved by replacing the oil cooler. Also, it will not be superfluous to rinse the automatic box with working fluid. Having done this, you can try to bring the unit back to life.
- If the branch pipe that connects the automatic transmission to the oil cooler is broken. In this case, all the lubricant will come out of the transmission in a matter of minutes, so the unit will simply stop working.
Disassembled automatic transmission
These are just a few of the reasons why an automatic transmission might not shift gears. A more complete list is presented in the table.
|The need to replace the clutches, breakage of the piston cuff, failure of the clutch rings or jamming of the valve body valve.||In this case, a car with an automatic transmission will only be able to go backwards, the forward gears are not included.|
|Breakage of clutches, piston cups, wear of o-rings, malfunction of the spline connection of the clutch drum or other damage associated with this unit.||In this case, the automatic transmission cannot switch speeds back, but the first and second gears, unlike the others, will work.|
|Faults in the cuff, piston rod of the brake band or its wear, problems in the operation of the brake package.||The car does not go backwards, all forward speeds are switched on normally.|
|Failure of the torque converter, breakdown of the oil pump gear, lack of lubrication in the system, clogged filter, wear of the clutches, breakage of the cuff, sticking of the valve.||In this case, the vehicle cannot go forward or backward. When trying to switch to any mode, the driver will not feel the characteristic jolt.|
|Failure of the torque converter, lack of lubrication in the system, clogged filter element.||The speeds, in principle, do not switch. When parking mode or neutral speed is activated, there will be a characteristic push to engage the gear, but the car will not go.|
|Valve sticking in the valve body.||The car can go backward or only at first and second speed. No other broadcasts will be played.|
|The splines of the turbine wheel hub, clutches are worn out, the clutch cuffs are out of order.||In this case, the car will slip when starting to move, but then the gears will engage well.|
|The pistons of one of the clutches are seized, the adjustment of the automatic control cable is disturbed, the clutches are welded to other discs as a result of long slipping.||The car can only drive at neutral speed.|
|Incorrect adjustment of the throttle valve cable, filter element clogged, throttle valve or centrifugal regulator valve is stuck.||In this case, gear shifting will be carried out at higher speeds, much higher than standard values.|
|The clutches of the automatic transmission were worn out, excessively large gaps appeared in the packages.||With such a breakdown, the inclusion of one or another speed will be accompanied by blows. In normal mode, the driver would feel jolts.|
|During long-term operation, the splines of the turbine wheel were cut.||The car cannot go forward or backward. In this case, the pressure in the transmission line will be normal.|
|The splines of the oil pump pulley are worn out. Also in this case, the slots on the reactor pulley may be worn out.||The car will not be able to go forward or backward, but there will be no pressure in the line.|
|Failure of the clutches. As the clutches wear out, the transmission fluid will contain more metal dust and disc shavings. As a result, dust clogs the filter element, and the pressure in the line begins to decrease.||The vehicle will operate normally until the lubricant warms up. After warming up, the car will start to slip and the car will not be able to go at all, neither forward nor backward.|
|In the design of the automatic transmission, one or several valves of the gear clutches have jammed or the torque converter is not functioning correctly as a result of jamming of the turbo wheel.||In this case, gear shifting will be completely impossible. When any mode is activated, the car will immediately stall, the driver will not even have time to press the gas pedal.|
|Moisture somehow gets into the structure of the unit. As a result, foam begins to appear inside the automatic box, and the oil pump stops creating pressure.||The gears can shift normally for a while, but the car will skid. Visually assessing the oil, you will see that it foams and turns light brown.|
How to fix the problem
Based on the data in the table above, there can be a lot of reasons for incorrect gear shifting on an automatic transmission. The troubleshooting methods will depend solely on the signs of a malfunction of your vehicle’s automatic transmission.
In any case, first of all, it is necessary to check:
- Transmission fluid level and condition. The level should always be normal, the same applies to the state. If there is little oil in the system, then the cause of its leakage must be identified and solved, and the liquid must be added to the system. If the quality of the TM is low, that is, there is dust from the wear of the friction discs in it, then the discs should be replaced and the lubricant changed. Do not forget to flush the system several times.
- Clutch conditions. As you can see from the table, clutch wear is one of the most common problems when it is impossible to switch gears. Diagnose and, if necessary, replace the clutches.
- Check valve function. If they jam for any reason, then this must be eliminated.
- Check the operation of the rocker, the wiring of the transmission system, as well as the speed controller. It will not be superfluous to check the brake band. If any of these elements does not work correctly, then the problem should be fixed.
If none of this helped, then the only way out is computer diagnostics. Unit diagnostics is carried out individually in each case, taking into account all the requirements of the automotive manufacturer. We will look at this process in general. So, you need a computer or laptop and a diagnostic cable.
The corresponding program must be installed on the computer:
- The computer is connected via a diagnostic cable to a special connector (diagnostic). The place of the connector will be individual in each case. Sometimes this connector is installed under the hood, but most often it can be found under the steering wheel on the driver’s side. It is usually hidden behind a plastic cover, so you need to open it.
- Once connected, a diagnostic utility is launched on the computer. It may take several minutes until the program and the car’s on-board computer are synchronized. After that, run the diagnostics. If possible, then before starting the check, select the “Checkpoint” item so that only the automatic transmission is diagnosed, and not all auto components.
- Upon completion of the diagnosis, the program will give you a list of error codes that indicate certain malfunctions. You need to decipher these codes in accordance with the documentation for your car. You can find part of the decryption instructions on our resource. Once you understand what the problem is, you can fix the problem.
Recommendations for use
- Forget about slipping. you need to eliminate it by any means. Automatic transmissions have a negative attitude towards slipping, especially on snowy roads and icy conditions.
- Always warm up the automatic transmission in winter. On a cold automatic transmission, the probability of failure of certain elements of the unit is very high.
- Don’t use neutral speed in vain. Mode “N” is considered a service mode, so limit its activation.
- Cars with automatic transmission should not tow anyone, since such gearboxes are simply not adapted to this. Loads have a very negative effect on the overall design of the unit. If you are planning to drive with a trailer, then consider this factor when buying a car.
- Cars with automatic gearboxes cannot be started from the “pusher”.
- Do not tow your vehicle on a cable. While driving, lubricant must always circulate in the transmission, but if the engine is turned off, the TM will not walk through the system. Of course, this negatively affects the operation of the unit as a whole.
- Always use only high quality transmission fluid recommended by your car manufacturer. Remember that the operation of cheaper lubricant over time can only harm the unit of your car, if it does not kill it at all.
Video “Automatic transmission device
You can learn everything about the device of the unit from the video.
How to properly shift gears on a bike
There are many gears in a modern bicycle. Every day, manufacturers are introducing an increasing number of speeds into their models. Whereas about a decade ago Shimano Alivio’s original line of components was designed for 6 stars in a cassette (i.e. 3×6 = 18 speeds), today bikes are fitted with 9-star cassettes in this class (3×9 = 27). Even recently popular (only a year or two ago) 8-star cassettes are now rarely seen, except on cheap bicycles. All this is done not only for the sake of marketing purposes, but also to improve the performance of the transmission: firstly, the speed range is slightly expanded, and secondly (and this is more significant), the jolts from changing the gear ratio become smoother. The load on the chain and sprocket is reduced, which increases the life of the components.
How to deal with all this economy correctly? How do I shift gears on my bike? Let’s figure it out. These tips come in handy for all riders with more than one gear on their bikes. Although no, just everyone, so that you can teach the mind-mind of your friends-acquaintances.
Learning to switch correctly
Each program, like a good joke, should be appropriate. On the ascent we go down, on the descent we go up. The pedal effort will tell you the right gear ratio for your driving conditions. If it becomes difficult to turn, you should switch lower, too easy. higher. But in any case, the load on the legs must be maintained, you need to rotate the pedals with tension. this is the only way pedaling will be effective.
Regarding the rotational speed (cadence). Each person is comfortable with their own cadence, at which the pedals will rotate with maximum efficiency. If the speed of rotation is lower than the rhythm you are comfortable with, then the forces will be wasted. If the cadence is incorrect, there is also a risk of injury. This is due to increased stress on joints and muscles. So pay attention to this point when driving.
You don’t need to pedal too quickly, otherwise you will quickly get tired. Finding the ideal frequency for yourself is easy, rely on sensations. I will only add that in addition to road conditions, the choice of gear and cadence is affected by the strength and direction of the wind, as well as the physical form of the cyclist at the moment.
Under any conditions, the goal is one. to pedal at a constant speed and constant effort on them, regardless of the selected gear. The same rhythm significantly postpones the onset of fatigue and increases endurance. Consequently, a significantly greater distance can be overcome.
In a nutshell about the structure of the gearshift system. Modern bicycles have two derailleurs. front and rear. They are controlled through the shifters: the left one is for the front derailleur, the right one is for the rear. The number of positions on them must correspond to the number of stars in the crankset and in the cassette.
Bicycle transmission device. The principle of operation of the front derailleur is quite simple. it moves the chain from one drive sprocket to another. The rear derailleur is more complex, since it is entrusted with the function of tensioning the chain, the length of which changes when moving from star to star. It has a double roller foot and a powerful spring. Thanks to this design, the chain does not randomly jump off or sag, and if necessary, with the effort of one finger, it quickly and clearly moves to the adjacent sprocket.
How to properly shift gears on a bike. basic recommendations
The pedals can only be turned forward when shifting. Some “unique” (mostly children, regardless of age) like to do the opposite, scoffing at the bike. Bad example to follow, agree. And the power gap does not contribute to effective acceleration in any way.
At the moment of shifting, it is necessary to slightly reduce the effort applied to the pedals. The shift to another gear will be smooth, without bumps, which positively affects the durability of the entire transmission.
With experience, you will intuitively find chainring and chainring combinations. If the switching system is not yet fully mastered by you, follow the position of the chain in one position or another. There are more than two dozen gears (the overwhelming number of bicycles today have 24, 27 and 30 speeds), but only two thirds of them can actually be used. The problem is severe chain misalignment that occurs when the outer chainring and inner (closest to the frame) rear chainring is used, and vice versa. The chain and sprockets in such sprocket combinations deteriorate quickly, and the rear derailleur is under increased stress. The coefficient of friction is generally higher, which requires extra effort from the cyclist motor. After all, it’s noisy.
Incorrect gear combination. Therefore, we remember: large chainrings and small rear ones are gear ratios for fast driving, a small front and large rear ones are for off-road and overcoming obstacles. It is impossible to combine “fast” with “slow”.
Take your time: shift gears one at a time, not several at once. Wait for the chain to move to an adjacent star, and only then continue switching.
Shifting uphill On uphill gradients, it is not recommended to change gears due to increased loads on the entire transmission. Therefore, choose a gear suitable for its slope in advance. Immediately exclude the large front one from the possible options, since it will be very difficult to climb up with it.
Keep your bike clean, lubricate and adjust mechanisms in time.
Most importantly, be smart about cycling.
Alexey, thanks for your answer 🙂 Of course, I don’t go with chain distortions First front. 3 rear (starting with the largest) Second front. 3rd-4th rear Third front. 4th-6th rear
Stern dynamic 1.0: front 3 speeds, back 6. True, I did not quite understand how to check if it is normal that one front one switches with three clicks on the handle. In the installed gears in front, the chain does not rub against the switch
The question is: the bike has three sprockets in the front and 6 in the back. The rear shifts properly. one flip of a coin. one gear. The front one is different. the divisions on the handle (on the steering wheel) are 6, therefore, in order to switch from one gear to another in the front sprocket, you have to move the handle (on the steering wheel) immediately to 3 divisions, because when translating to only one chain, it is not translated, but simply starts rubbing against the shifted switch. This is normal or you can somehow adjust?
Bicycle does not shift gears
Correct and quick change of bicycle gears is a rather important element when riding, as it is responsible for the safety of the life and health of the cyclist, regardless of who he is: a man or a vehicle. For the gearshift mechanism to be fully functional, it must not only be serviced afterwards and in advance. but also customize. It doesn’t take long to figure out how to adjust the front derailleur on your bike, just follow the instructions below.
The front derailleur on a bicycle is a strip of steel attached to the frame of the bicycle and has free play, both to the right and to the left. Moving to one side, he transfers the chain to another sprocket (smaller or larger in size).
The mechanism is driven by a steel cable, which is connected to a shifter on the steering wheel.
Important! The design is fairly simple, but in order for the speed setting on the bike to be successful, all actions must be performed carefully and accurately.
How to install?
Installation of the front derailleur on a bicycle is carried out in accordance with several points.
Just like the installation, the front derailleur on the bike is replaced.
Adjusting the front derailleur on a bicycle is done after the mechanism has been re-installed or replaced. This may require a specific tool (curly screwdriver and wrenches with a minimum pitch).
Important! The smaller the clearance between the derailleur frame and the chain, the easier it will be to change gears.
From the instructions above, you can understand how to set up the front derailleur on your bike with your own hands. But you should be aware that the correct setting does not always work the first time. Sometimes only practice will help to achieve the desired result and, perhaps, the process will have to be repeated several times. But you need to do everything so as not to overdo it, because otherwise you will need to repair the front derailleur.
If you want everything to work out the first time, then watch both videos.
Sometimes a slight bending of the front edge of the frame outward can help. This can be done with an adjustable wrench, but fortunately is rarely required for modern switches, but has been used quite widely on older.
“Fitting” the front derailleur
As the rear gear shifts, the direction from which the chain comes to the derailleur changes slightly. As a result, sometimes it becomes necessary to “adjust” the position of the derailleur when changing the reverse gear, even while remaining on the same front sprocket. “Fit” involves a slight movement of the frame by the shifter, but not enough to change gear, but only to eliminate friction against the sprocket.
On older shifters designed for friction shifters, “fit” was simply implied, but modern discrete shifters can almost always be set so that this fit is not necessary. For perfect shifting, you need to use a derailleur designed for the specific sprocket size, and the sprockets must be completely flat. The lower the derailleur frame is set to the sprocket, the less adjustment is required.
If the system requires a “fit”, you must do it. If the chain rubs against the derailleur frame, you will erase the frame so that you simply cannot expect any decent switching from it.
“Chainline” is the distance from the symmetry plane of the frame to the chain / sprockets.
Front derailleur problems are often caused by an incorrect chain line, meaning the chain is too close or more often too far from the bike’s centerline. This is usually caused by the wrong carriage selection for the system.
Often shifting problems are not caused by improper operation / setting of the derailleur, but by too much friction in the cable that controls it. High friction usually results in slow return of the frame by the derailleur spring to the smaller sprocket.
Typically, these problems occur in the short length of the shirt leading from the pen to the switch. The front end of the shirt is exposed to dirt flying off the wheel and therefore rusts quickly, which seriously impairs shifting performance. This loop should be quite long so that there are no sharp bends. This loop is too short on most bikes.
Another problem area is where the cable runs under the carriage. In addition to slow shifting, friction can cause spontaneous shifting under load.
When you cut the shirt, the plastic flattens a little. It is useful after that to clean and round off the end, for example, with an awl. The shirt forms a strong loop just in front of the rear derailleur. I recommend that you first bend a piece of shirt to an approximate shape and only then cut it off completely.
If you cut a straight shirt, all the longitudinal wires are the same length, so when you bend it, the end of the shirt becomes oblique, since the wires going inside the bend and outside it travel a different path. I (Sheldon, of course) believe that cutting off already folded shirts makes the joint of the shirt end smoother. Also, at the end of the shirts, there should be special tips to keep the correct shape of the end of the shirt, and also prevent the shirt from delamination.
With modern jackets, cable lubrication is no longer required. Indeed, it often makes things worse because of the stickiness of the lubricant itself. However, a little light oil on the part of the shirt going to the derailleur won’t hurt. it will prevent rust.
Cables and shirts vary greatly in quality. I would recommend only buying the best cables and shirts. However, it is still possible that the switch spring cannot exceed the friction in this loop.
Cable attachment (rear)
Attaching the end of the cable to the derailleur bolt often causes problems. If it is approached at the wrong angle, the geometry of the parallelogram will be distorted, and therefore it will be difficult to achieve normal movement of the derailleur throughout the gear range. The switch typically has a groove or washer with a curved end to indicate that the cable is attached correctly.
For example, on the derailleur pictured above, the cable is not properly attached. You can see the groove between the cable and the bend in the washer.
Cable holder (front)
In the case of front derailleurs, some newer models are designed so that there are two ways to attach the cable. If the cable runs outside the bolt (further from the parallelogram pivot), the frame moves less for a given cable movement. This provides easier handling and easier fine adjustment. If the cable fits from the side of the parallelogram hinges to the bolt, the frame moves further for the given cable movement. This is often required for discrete gear changes. Skip / Spontaneous Switching
Do the pedals sometimes slip when you put in a lot of effort? This is a common complaint, especially when the rider is pedaling. Indeed, this dangerous condition is a good reason to stay in the saddle and shift into low gears rather than standing up and riding high.
While a switch is often blamed for overshoot / jumping / spontaneous switching, it is very rarely caused by a switch malfunctioning.
Chain hopping can be associated with one of two unrelated problems: overshoot or spontaneous switching. The first step in solving a problem is to determine the type of problem: Overshoot involves the chain bouncing over the tops of the sprocket teeth under load. After this jump, the chain remains in the same gear. It is usually caused by wear on the chain and / or sprockets.
This is most likely to happen on the smallest star of the cassette, especially when used in conjunction with the smallest star in the system. This finding is discussed in more detail in the article on chain wear. Sometimes overshoot is also caused by bent links.
Spontaneous shifting feels exactly the same as overshoot, only after the jump the chain is already in a different, higher gear (smaller sprocket). The reason for this is a combination of frame flexibility and cable friction.
If you’ve managed to tweak the rear derailleur, then adjusting the front derailleur will seem like child’s play. Everything is much easier and faster here.
Someone might ask: why did we mention the rear derailleur? Yes, because you can adjust the front derailleur only after successfully setting the rear (read how to do it).
Preparing for setup
Before we move on to setting up the derailleur, we need to make sure that it is properly installed on the frame:
First, the derailleur frame should be 2 millimeters above the teeth of the largest chainring (see photo below).
Secondly, the frame must be strictly parallel to the chainring block of the bicycle.
The switch must be washed and lubricated before adjusting (just drop a drop of grease on all moving joints). It is also necessary to clean the drive cable and “jackets” from dirt. If the cable is worn out, replace it.
Move the chain to the largest sprocket at the back and the smallest sprocket at the front.
The shifter has a drum for adjusting the tension of the drive cable. This drum must be scrolled clockwise without twisting two or three turns all the way.
Loosen the screw that secures the drive cable.
Adjusting the front derailleur
Operation 1. Turning the adjusting screw L, achieve such a position of the switch frame, in which the chain will be at a minimum distance from its inner surface (from the side of the carriage), but will not touch the frame.
Step 2. Secure the drive cable. Pull it lightly with one hand and tighten the mounting screw with the other. If there is a special washer with a groove under the fastening screw, make sure that the cable lies in this groove.
Step 3. Move the chain to the smallest sprocket at the back and the largest sprocket at the front. Turning screw H, set the switch frame so that the chain is at a minimum distance from the outer surface of the frame, but does not hit it.
Now check how the switch operates under load. The chain must move freely from star to star and while driving must not touch the derailleur frame.
You may well need more fine tuning of the front derailleur. By rotating the drum for adjusting the cable tension on the shifter, you can achieve a slight displacement of the switch frame to the right or left.
Note that in some cases, even with the correct setting of the front derailleur, the chain will still hit the front derailleur frame. Most often, the reason is too much chain skew, which occurs when driving in extreme gears: 1 (chainring). 9 (rear sprocket), 1-8, 2-9, 3-1 or 3-2. Most bike manufacturers do not recommend these gear combinations.
Well, traditionally, you should not expect perfect gear changes from unnamed Chinese derailleurs.
After completing the adjustment, wipe off excess grease from the switch with a clean cloth.
On this page you can also watch a training video from the Shostka-Velo cycling club on setting up the Shimano front derailleur.
The purpose of this manual is to help you understand how to properly adjust the front derailleur on your bike. It may differ slightly on different bikes, but the procedure itself is about the same.
This guide will be very helpful if your bike has poor gear shifting and you want to adjust the front derailleur correctly. Once you finish adjusting the front derailleur, you’ll be amazed at how well your bike shifts. Also, this guide will be helpful when installing the front derailleur for the first time.
If this is your first time trying to adjust the front derailleur on a bike, then you need some technical skill. And the best way to get them is to try and tweak the shifter. tinker with it yourself! To make it easier to understand the process of adjusting the front derailleur, there are many photos in the article.
The job of the front derailleur on a bicycle is to move the chain from one sprocket to another. The derailleur holder is moved with a cable. When the tension of the cable is released, the holder is displaced inwardly under the action of the spring. A correctly adjusted front derailleur should move the chain clearly and smoothly between the chainrings. When pedaling the bike, the holder should not rub against the chain.
To adjust the front derailleur, you need the following (see photo above):
Now let’s get down to adjusting the front derailleur! Most importantly, do everything with pleasure.!
Adjusting the height of the front derailleur.
The first step to properly setting the front derailleur is to check your altitude. If the holder is too high above the drive sprocket, then it will not change gears well. If it is too low, then it will not move the chain from star to star at all.
- Shift the derailleur so that the chain is on the middle drive sprocket. This will place the outer holder plate directly above the outer star.
- The distance between the teeth of the outer sprocket and the bottom edge of the outer holder plate should be 1. 2 mm. A coin will serve as a tool for measuring the gap, since its thickness is approximately 1.5 mm. The coin should clearly fit into the slot (see photo).
- To change the derailleur height, first loosen the cable tension by shifting to the smallest drive sprocket. Then loosen the speed selector retaining bolt, adjust the height, and retighten the bolt. Switch back to the middle guide sprocket and check the holder height (see photo).
- Repeat this procedure until the distance between the teeth on the outer drive sprocket and the bottom edge of the outer carrier plate is 1 to 2 mm.
Note: The front derailleur clip will usually leave a mark on. by which you can navigate when changing the height.
Front Derailleur Steering Angle Adjustment.
The front derailleur holder should be approximately parallel to the chain. The accuracy of the angle of rotation determines the clarity.
- Shift gears so that the chain is on the outer rear sprocket and the outer front drive sprocket.
- Examine the chain from above. The chain must be parallel to the outer plate of the derailleur holder (see photo).
- If the derailleur requires a turn, move the inner drive sprocket down to loosen the cable tension.
- Loosen the locking bolt and turn the speed selector to the correct position. Make sure this does not change the height. Tighten the locking bolt again (see photo).
- Move the outer sprocket back and check if the derailleur is level (see photo).
- Repeat this procedure until the speed selector plate is parallel to the circuit.
Note: The front derailleur clip usually leaves a mark on the frame to guide you when changing the steering angle.
Position of the front derailleur stop screws.
The stop screws limit the movement of the front derailleur in the inward or outward direction. The stop screws are identified by the letters “L” and “H”. Screw “L” limits the movement of the holder outside the inner sprocket, and the screw “H”. outside the outer sprocket.
If there are no marks on the screws, then it is possible to establish which of them is responsible for what only empirically. Switch to the inner guide star. Turn one of the screws first clockwise and then counterclockwise. If the speed switch moves, then it is screw “L”. If not, check another screw. When turning the screw “H”, the speed selector must not move. Mark the screws to know which one is which.
Adjusting the screw “H” / “L” of the front derailleur.
- Switch to outer rear sprocket and outer driving chainring (see first and second photos).
- Pull the cable by hand to make sure that the “H” screw is not affecting the gear selector (see photo).
- While keeping the cable taut, check the clearance between the chain and the outer retainer plate. It should be about one millimeter (see photo).
- Pedal your bike slowly, observing the clearance. Achieve the required clearance by adjusting the screw “H” where the drive sprocket is closest to the chain during rotation.
Front derailleur indexing adjustment.
- Switch to inner rear sprocket and middle front drive sprocket.
- The gap between the inner plate of the holder and the chain should be as small as possible, but there should be no friction. Spin the bike pedals to make sure that there is no friction in all places during rotation (see photo).
- To reduce the gap, increase the cable tension by rotating the adjusting drum (see photo).
- If the chain rubs against the inner plate of the holder, reduce the tension on the cable by rotating the adjusting drum (see photo).
- If the adjusting drum is unscrewed to the limit, then return the cable tension to its original position. Unscrew the adjusting drum all the way in the opposite direction. Switch to the inner chainring. Loosen the cable tightening bolt, pull gently and retighten the bolt. Repeat the cable tension adjustment as described above (see photo).
Completing the front derailleur setting.
Congratulations! You have correctly adjusted the front derailleur on your bike. Shifting between the front drive sprockets should now be quick and smooth.
We hope this tutorial was helpful to you. You can now enjoy cycling!
Adjustment, front derailleur setting. it’s not difficult if you do everything carefully and consistently, but first you need to. and then proceed to the front.
The whole process can be divided into three stages:
1) Preparation; 2) Adjustment; 3) Checking;
To set up we need:
1) Shaped screwdriver;
4) Key for 9 (in some cases, you need a 4-5 hexagon);
5) Cable and cable jacket (if yours are in poor condition);
The first stage is preparation.
First, check and (for this, loosen the tension cable and take it out of the shirt), make sure that the cable is not unraveled anywhere, the cable shirt is not “wrinkled”. If there are no kinks and unweaving, and the cable still moves tightly in the shirt, clean it from dirt, sand and lubricate.
Twist the thumbscrew, which is located on the shift coins, almost to the very end (leave a couple of turns for adjustment). At this stage of preparation is over.
The second step is setting the front derailleur.
Position the derailleur so that, if you were looking at it from above, the derailleur frame is parallel to the chainrings. (to adjust the height and angle of the switch, loosen the clamping bolt)
In order to adjust the height, set the chain on a large sprocket, the gap between the frame and the large sprocket should be 2-3 mm. The smaller this gap, the better switching
If you look at the switch from above, you can see two adjusting screws H.High (high) and L.Low (low). these screws are responsible for adjusting the “chain blockage”.
Place the chain on a small sprocket in the front and a large one in the back.
Begin to rotate the L.Low screw (low) until the chain is as close to the inner plate as possible, but make sure that the chain does not hit the frame when pedaling. Next, pull the cable with pliers and tighten the cable fastening screw.
Now you need to do the same with the H.High screw. We put the chain on the big star in the front and on the small back. Turn the screw H (High) until the chain is as close to the outer plate as possible, but so that when pedaling the chain does not touch the frame.
Now you need to check how the switch works by rotating the pedals (put the bike on a stand or hang the rear wheel), step by step change gears in both directions. If it does not switch well from large to small stars, it is necessary to loosen the cable by rotating the “lamb” on the coins, clockwise, and if it does not rise well from small to large, counterclockwise.
Stage three. checking the front derailleur.
After we have checked the operation of the derailleur on weight, we need to do it under load, and go, changing gears. The front derailleur should work smoothly and clearly, the chain should not rub against the frame.
What problems can be when setting the front derailleur?
1) Incompatibility of the front derailleur and system.
It happens that when you replace or install a new switch, you have the wrong switch. In general, they are of three types: with an upper cable pull, with a lower cable pull and universal, and each switch is designed for a specific system and number of teeth. Therefore, when buying a switch, look what you had, and if you don’t know, take it with you for a sample.
2) It is not possible to adjust the front derailleur, the chain constantly rubs against the frame
First, check the parallelism of the switch installation, if everything is ok, check the system, if it is bent, if the sprockets are even, make a couple of pedals and look at them, the stars should not change the axis of rotation.
3) Friction of the chain on the derailleur frame when at a speed of 3-1.
Do not forget about the concept of “chain skew” in the position when the chain is located diagonally it is not recommended to ride. this can lead to chain stretching and damage to the front derailleur.
Also, when changing gears, do not forget to relieve pressure on the pedals.
If you are unable to adjust the front derailleur, please contact us yourself, ours will be happy to help you.
Video. how to adjust the front derailleur:
What is gear shifting for?
Riding on a flat road, uphill or downhill requires different efforts from the cyclist. On a single speed bike, there are no options, since there is only one gear. And those who have experience climbing a mountain on a single speed bike know how difficult it is. But in the case of a multi-speed bike, new possibilities appear. you can adjust the load. On a bike equipped with multiple gears, for example, it is much easier to ride uphill. Let’s figure out how the gearshift occurs.
What is gear shifting
The essence of switching speeds is to drag the chain from one star to another. And various combinations of chainrings and chainrings allow you to adjust the cyclist’s load. But first, let’s turn to the bike drivetrain.
The transmission is all the parts and assemblies of the bicycle that transfer energy to the rotational movement of the rear wheel. The transmission consists of a carriage, a crankset, a chain, sprockets or cassette (or ratchet), front and rear derailleurs, as well as shifters (they are also sometimes called shifters).
Gear shifting occurs via shifters located on the steering wheel. Using the rear derailleur shifter, located on the right handlebar, the chain is thrown between the rear sprockets, and using the front derailleur shifter (it is on the left handlebar) between the front sprockets.
Most multi-speed bikes have three drive sprockets and six to eight driven sprockets. The fore stars are counted from small to large, and the rear stars, on the contrary, from large to small.
Types of speed switches
There are two main types of speed switches. external and internal shifting.
Internal switching mechanism
City bikes often use an internal gearshift mechanism that is hidden inside the rear planetary hub (for example, the new Forward Surf 2.0 cruiser). Planetary hub bikes have only one chainring and one sprocket. The number of speeds / gears in planetary bushings is usually from 3 to 7. The planetary hub has a rather complex internal structure.
Pluses of planetary bushings: they withstand adverse weather and road conditions well, since the mechanism and all its parts are enclosed in a case and, as a result, are reliable and durable; you can switch speeds without pedaling.
Cons of planetary bushings:. heavy weight;. very difficult repair, impossible in field conditions.
External switching mechanism
This type of derailleur is used on most multi-speed bikes, from city bikes (like the Forward Dortmund 2.0) to mountain bikes (like the Forward Agris 27.5 3.0 disc). Gear shifting is carried out using the front and rear derailleurs.
Front derailleur The front derailleur transfers the chain between the chainrings. The derailleur design has a moving frame within which the bicycle chain runs. When shifting gears with a shifter, the frame moves and becomes above the desired sprocket, which ensures the movement of the chain to this star.
Rear derailleur The rear derailleur is a spring-return mechanism that moves a frame (or foot) with rollers between them within a transverse axis. In one direction, the switch is moved with a cable, and in the opposite direction, with a return spring. When you move the derailleur, the chain passed through it is thrown from one rear sprocket to another, and the chain tensioner automatically removes the chain slack.
Advantages of external switches: simple design low weight low price high number of gears
Disadvantages of external derailleurs:. highly susceptible to unfavorable external factors. need for adjustment and maintenance. risk of breakage if the bike falls. it is impossible to change gears if the bike is stationary
Correct star combinations
Choose speeds based on the terrain and your physical capabilities, and so that the chain does not tilt. You can make sure that there are no distortions simply by looking at the chain. If it moves parallel to the frames of the front derailleur, then the selected speed is optimal. Skew occurs when the chain is on the front large chainring and on the rear, also large.
Let’s see which sprocket combinations are applicable on a bicycle with three chainrings and eight chainrings. The main principle is simple: it is necessary that the combination of front and rear sprockets is always approximately in the same vertical plane.
The large chainring is matched with 4-8 rear chainrings. This combination is optimal when riding on a flat road.
The middle chainring is matched with the 3rd to 6th chainrings. This combination is suitable if you are riding on lightly rough roads, or if you want to give yourself more physical activity while riding on a flat road.
The small chainring is matched with 1 to 3 rear sprockets for uphill climbing. In this case, much less effort is required from the cyclist when pedaling, but more frequent pedaling.
Incorrect combination of front and rear sprockets, leads to a strong misalignment of the chain, shortening the life of not only the chain, but also the derailleurs.
How to adjust the speed switches. How to switch gears correctly
Correct gear shifting allows you to ride easier and more comfortable with less effort, as well as increase the service life of all elements of the bicycle transmission. We have prepared several rules and recommendations on how to properly switch speeds on a bike:
Starter bikes have the cheapest transmissions, and the gears are poorly shifted and jammed. In these cases, the owners cannot do anything, since they realize that they are managing cheap garbage. But after a while, faced with similar switching problems after buying more expensive equipment or a bicycle, people tend to be puzzled.
The point here, of course, is not fate, but the wrong attitude to technology. An experienced cyclist can quickly determine the drivetrain level. The point is that its disordered work is not always associated with the class, but more depends on the setting and state. Let’s try to list most of the factors causing such problems.
If you happen to take off your shirts, and the cable is not dirty or damaged, it is worth wiping it with a rag, then sprinkling Teflon grease on it, which will leave a thin slippery layer on it. Shirts worth shedding WD40. It is necessary to extract all the dirt to the maximum, because during the ride it is likely to have accumulated a lot. It is important to consider the following thing here. the cables and shirts do not need lubrication. It is strongly not recommended to use thick lubricants, like grease. After a couple of trips on the ground, a consistency will accumulate in the shirts, consisting mainly of dirt.
There are teflon-coated cables that are slightly more expensive than conventional cables. The difference in gear changes is already noticeable on the first drive. Of course, the coating wears off over time, especially in places of frequent interaction with the shirt. Solution: Supplied with them in sets, spouts that prevent the ingress of dirt and dust. If we talk about shirts, then they should not have long or short sections. Better to spend a little, but make the shirt a single whole. In places of bends, friction increases many times and the formation of dirt does not keep you waiting.
Rear derailleur free play To check for play, simply move the rear derailleur. During such a procedure, he should be absent. With low free travel, especially in the minimum transmission groups, there is nothing to worry about. But during operation, the backlash tends to increase, and then delays in switching or fuzziness can begin. If everything is normal with the ropes and the rooster, fine tuning will help get rid of the negative effect.
Poor gear shifting on a bicycle is a common problem. Dirt stuck in shirts, a bent bracket, a derailleur free play, poor tuning. it all comes together. Many consider this to be the norm and continue to drive. The speeds are switched according to the principle “two forward, one back”. You can not do it this way! Any drivetrain, even the smallest Shimano Tourney, needs to precisely flip the chain when shifting.
Maintaining the transmission on time and keeping the components clean are 2 conditions to avoid problems while riding.
One of the reasons for poor gear shifting can be an unlubricated or dirty chain. We share with you a video on the correct ways to clean the chain.
Original publication. on cortobike.ru
Transmission repair stages
Repairs include adjusting the front and rear derailleurs, as well as checking the condition of the cables, chain, cassette and rollers.
- Unscrew the bolt holding the cable.
- Disassemble the shifter and remove the cable from it and from the shirts. Shirts are also recommended to be replaced!
- Clean shirts and put a drop of oil in them for better cable glide.
- Thread the new cable through the shifter and then into all shirts.
- Start configuring the switch.
- Bite off the excess part of the cable and secure the end with a special tip.
Over time, the chain deteriorates. It is recommended to keep several chains in stock and change them every 100 kilometers, because the wear of the chain will deteriorate the cassette. Multiple chains will wear out more slowly and your cassette will last longer. You can determine the state of the chain using a special tool. It is impossible to repair the chain, you just need to replace it if necessary.
If the chain is in good condition, simply remove it, clean and lubricate. Remove excess with a napkin or dry cloth.
Make sure the cock is level first. If it is still bent, you can contact the service to straighten it, or try it yourself. You can also simply replace it. For 2016, for roosters are only about 300-900 rubles. Do not even try to tune the derailleur with a bent cock, as the gear adjustment on the bike will fail.!
Some firms produce the so-called cock guard, which is attached to the frame. Do not buy it under any circumstances! A rooster is a consumable component that can and should be replaced if it breaks. When hitting this very protection, the cock will remain intact, but the frame may crack. The frame is harder and more expensive to change.
When you are convinced that the rooster and the rope are in good condition, you can proceed to the actual setting.
Place the chain on the largest chainring in the front and the smallest in the back.
Unscrew the bolt holding the rear transfer cable.
By rotating the bolt marked “H” you need to make sure that the switch rollers lie in the same plane with the desired sprocket.
Then pull the cable slightly and tighten the bolt holding it. Over-tensioning the cable will make the transfer difficult.
Shift the speed to the lowest (i.e. the largest star in the back and smallest in the front).
Rotate screw “L” until the derailleur rollers line up against the large star.
Check if gear changes are good.
If shifting is not correct, use the thumbscrew on the shifter, which changes the cable tension.
Now that you have set up the rear derailleur, you are ready to adjust the front.
It is important to set it up especially accurately, since if the adjustment is not good enough when changing speeds, the chain can fly off or even break. The sequence of your actions will be as follows:
Use the rear shifter to shift to the middle sprocket so that there is no strong chain skew.
Then put the chain in first gear and unscrew the bolt securing the cable.
Use the screw “L” to move the transfer frame so that the distance from the chain to the switch on the left and right matches.
Without too much tension, place the cable and secure with the bolt.
Switch to the biggest star in the front.
Tighten the screw “H” so that the chain is again exactly in the middle of the frame.
Check adjustment results and achieve maximum shifting accuracy with the thumb on the shifter.
If the shifter triggers are too tight, loosen the cable tension.
Drive only at speeds that will not cause the chain to tilt too much. For example, you cannot set the speed to 1/8, 1/10, 3/1 (the first number is forward gear, the second is reverse) and so on. For the smallest front chainring, you can turn on 1–4 speeds at the rear, for the middle. 3–7, for the largest. 7. If you nevertheless put an incompatible gear, there will be a risk of chain jamming and spinning, as well as an increase in its wear rate.
On a speed bike, fast gear changes are very important, especially if you are competing. Transmission repairs should be carried out before the race, and then after, as aggressive driving may cause the shift adjustments to go off. If you do full maintenance of your bike at least once a season, then it will serve you for a very long time.!
What parts help to adjust the speed switches
The multi-speed mountain bike or city bike is equipped with several gears and offers new possibilities. It is much easier to conquer peaks, ride on irregularities, even perform various tricks on it. To enjoy cycling, you need to set the speed switch correctly.
Those who first decided to understand the switch mechanism on their own should first familiarize themselves with the details of the transmission and their functions.
We will not dwell on each part of the bike in detail. Let’s consider just some of the elements that make up the transmission.
- the front derailleur assists the chain in guiding the chainring. Attaches to the frame near the pedals;
- the system is part of the front derailleur. It also consists of stars, different in diameter and number of teeth, which are attached to the connecting rods with special bolts;
- the rear derailleur assists the chain to follow the cassette drive sprockets. Located in the rear wheel area;
- cassette / ratchet is part of the rear derailleur. Consists of several stars, different in diameter and number of teeth. On expensive bicycles, the cassette is attached to the drum. In the cheaper ones, there is a ratchet in place of the drum. The latter can also be seen on older bike models;
- chain. part of the transmission, which must be periodically lubricated with special oils and washed;
Speed change mechanism
The work of the rear and front derailleur is as follows: if the cable is pulled, the derailleur frame moves the chain to higher sprockets. If, on the contrary, weaken the cable, then the frame will throw the chain onto smaller stars.
The speeds are switched with the help of shifters (coins) located on the steering wheel. The rear derailleur is adjustable with the right shifter. Thus, the chain jumps between the rear sprockets. And the front derailleur is adjustable with a shifter on the left side. So the chain jumps among the chainrings.
Gear shift types
Before making any adjustments, determine what kind of gear shift your bike has. There are 3 main types of switches.
- External switching mechanism.
- Internal switching mechanism.
- Combined type.
Internal gear shifting for mountain bike
The basis of this design is planetary bushings. This mechanism does not use cassettes. The transmission includes only 2 stars: front and rear. The whole mechanism is hidden inside. There is usually no front derailleur either.
This mechanism is often found on road bikes, pleasure bikes, folding bicycles and city bikes. The system itself is located inside the rear planetary hub. This type of shifter can be seen, for example, on the Forward Surf city bike (3 gears).
External shifting on a speed bike
The outer type belongs to most multi-speed bicycles. It is used on both mountain and city walking models. The mechanism is made up of gear shifters and stars that form a cassette or system. Variable speed with rear and front derailleurs.
This type of gear shifting can be seen on both the Forward Dortmund city bike (7 speeds) and the Forward Agris mountain bike (24 speeds). You can customize this switch yourself by examining the mechanism.
Bicycle chassis design, principles of operation. video. Combined mechanism
The combined type is a combination of external and internal mechanisms. It attaches to the bike’s rear wheel hub.
This mechanism is extremely rare, since it has collected all the negative aspects of both external and internal gearshift systems. It is configured only by a professional.
In the modern world, there are many companies that create equipment for bicycles. The best quality models are made by corporations such as Shimano (Japan) and Sram (America), producing entire lines of derailleurs.
Devices for professionals:
- Shimano XTR, Sram ESP 9.0 and Sram ESP X.0 are leading the way in price and quality. They are mainly used in competition bicycles. They are characterized by low construction weight.
- Shimano deore xt, Shimano Saint, Shimano slx finished second in the same category. Used in bicycles with 27 gears.
- Shimano Deore LX, Shimano Dura-Ace, Shimano Hone. 3rd place. They are designed for devices with the maximum number of speeds.
Sports bike lines:
- Sram ESP 7.0 and Shimano Deore are similar designs. Made from highly durable components and designed for 24 gears.
- Sram ESP 4.0, Sram ESP 5.0, Shimano Nexave and Shimano alivio are cheaper than the professional line. They can handle up to 24 speeds and are designed for touring bike models.
Hobbyist Switch Line:
- The Sram ESP 4.0, Shimano C201 and Shimano acera are bundled with cheaper entry-level hybrids and mountain bikes. Withstand up to 24 gears.
- Sram ESP 3.0, Shimano Nexus and Shimano altus are designed for touring, city bikes.
- The Shimano tourney is built for a calm, smooth ride. Shifts 21 gears.
There is no fundamental difference in the adjustment and operation of different switch lines from the same company. For example, different Shimano derailleur groups work the same and are interchangeable. Let’s say that the drive of eight-speed Alivio, Altus, Acera switches can be equipped with nine-speed Deore, Deore XT, Deore LX, XTR systems and vice versa.
What can affect the quality of the switches
It is important to find out what caused the problem.
This defect is regulated by a drum on a shifter.
- When the chain moves silently and bounces on large stars with difficulty, then the cable is stretched. Turn the drum clockwise until the part is tensioned to the desired position.
- In the case when the chain does not want to go down to small stars, relax the cable by turning the drum counterclockwise.
- Check the operation of the speed switch. Twist the drum if necessary. Adjust until the chain bounces smoothly.
If the part is damaged, it must be replaced.
- Unscrew the fixing screw on the lintel.
- Disassemble the shifter to remove the cable.
- Insert a new one, treat with special grease.
- Run it through the shirts and put them back in place.
- Secure the new cable to the derailleur.
Changing the cable on the bike. video. Parallelogram spring problems
For better operation of the return spring, you need to wash it. Then lubricate after cleaning.
Rooster bent or broke
If the foot of the rear derailleur is oblique, then the mount is bent. You can fix this defect yourself.
- Hold the foot with one hand and grasp the switch with the other.
- Carefully, without sudden movements, level the position of the cock until the rear frame is level.
Deformation of the switch
A common cause of such a breakdown is a blow from a bicycle. Usually the rear derailleur suffers, the front derailleur is very difficult to bend. After a breakdown, it is worth checking which parts are broken.
- If this is a frame. align or change the part.
- If the screw that adjusts the chain tension or the eyelet that secures this screw breaks, then it is better to replace the parts. Otherwise, the speeds will switch very badly.
How to adjust the rear derailleur
The rear derailleur is a machine that transfers the chain from one sprocket of the rear wheel to another. Today, the vast majority of high-speed bicycles are equipped with such a switch.
The rear derailleur consists of the following elements.
- Switch frame. The number of bike speeds depends on its length.
- Two rollers that guide the chain: guide and tensioner roller.
- The mechanism itself (parallelogram).
- Fixing bolt.
- Low gear stop. screw marked L.
- Top gear stop. screw marked H.
- Cable guide groove.
- Tensioner adjusting screw.
Setting the rear derailleur is needed if the mechanism is out of order, the chain jumps over the necessary stars, the speed does not switch, a grinding or loud sounds are heard. You can configure the mechanism and debug its work yourself. You will need a Phillips screwdriver and a hex wrench
First, make sure the derailleur is vertical and parallel to the bike. If everything is in order, you can proceed to the setup. For convenience, turn the bike upside down, placing it on the saddle and handlebar, this will give access to the switch itself and the adjustment screws.
- First, lower the chain to the smallest sprocket. Do this with the shifter on the right handlebar of the bike, it is she who is responsible for the rear derailleur.
- Loosen the screw holding the cable. This is done in order to unlock the switch.
- Prepare a screwdriver and find the screw with the Latin letter H.
- Move the switch so that the sprockets on which the chain lies (one star on the cassette, two stars on the switch) are in the same plane, that is, they form one line.
- Take the cable with your hand. It must be pulled out as much as possible and fixed by tightening the screw.
- Check if the switch is working properly. If it does not go well on large stars, turn the thumbscrew counterclockwise, pulling the cable.
- Now move the chain to the smallest star using the shifters.
- Find the screw with the Latin letter L.
- Change the position of the derailleur so that the largest sprocket in the cassette lies in the same plane with the derailleur foot, forming a straight line with it.
Front derailleur adjustment
The front derailleur is less common than the rear derailleur. Bicycles with this device are cheaper. The front derailleur moves the chain to the stars of the system. Moving from side to side, he pushes the chain to the next star.
Front derailleur device.
- Switch frame. A chain passes through it, this is the main element when switching speeds. She moves to the sides in front of the leading stars.
- Parallelogram. the mechanism itself (speed switch). Includes spring.
- Fastening to the frame.
- Upper stop L.
- Lower stop H.
- Fastening the cable.
The main problem with the front derailleur is that the chain hits the frame when driving. You can fix this problem yourself.
Setting the correct operation of the mechanism
- First you need to put the smallest star in front, and the maximum at the back. To do this, turn the pedals while pressing the shifter.
- Use a hex key to lower the screw holding the cable.
- Take a screwdriver, find screw L. Move the frame so that the distance from its inner part to the chain is about 4 mm.
- Reattach the cable. To do this, tighten it with your fingers and tighten the screw that presses against the cable.
- Now you need to adjust the second star. Put the smallest sprocket on the rear derailleur first and change the front derailleur to the old.
- See if the chain is touching the outside of the frame. If the problem persists, tighten the cable with the thumb on the left shifter. Turn it counterclockwise until the chain is in the desired position. The distance from it to the frame should be approximately 3 mm.
- Move to the third star. If the chain touches the frame, use a screwdriver to adjust screw H. It is necessary to increase the gap by moving the frame outward.
How to change gears on any bike from Merida to ladies
To ride easily and comfortably with less effort, you need to switch gears correctly.
- When you hear extraneous sounds when changing gears, the transmission has not worked. You need to squeeze the lever of the shifter.
- Use the rear derailleur if you want to conquer the top.
- It’s better to change gears before you start climbing higher ground.
- Change gears on the move and don’t jump over multiple stars at once.
- Release pedal pressure while changing speeds. So the switching will be smooth and correct.
Varieties of mechanisms
Regardless of the design features, each bicycle gear mechanism allows the cyclist to efficiently distribute his efforts to pedaling, taking into account both the pressure and the speed. This makes driving on an obstacle road as easy as on smooth asphalt. The whole work of the bicycle transmission is based on changing the gear ratio between the rotating wheels of the vehicle and its pedals.
This principle is common to all types of mechanisms, which can be represented as an external, internal or combined system.
The first option is found on pedal vehicles much more often than others. Its work is based on the functioning of two switches at once, installed in the front and rear. To understand how gear changes are carried out on a bicycle, you should consider each of the mechanisms separately.
Front external flip mechanism
It is a structure with a moving frame inside that passes the chain through itself. Thus, when changing gears on a bicycle, along with the movement of the frame itself, the chain also moves to the desired sprocket.
The principle of operation of the mechanism is still not its only parameter when choosing, since such designs can also differ noticeably from each other in terms of such features as:
- method of attachment to the body;
- attachment angle relative to the bike body;
- cable attachment option.
In this case, the gearshift cable of the bicycle can go into the derailleur from above, from below. It is also possible to use both options. The second parameter must be selected with special attention in order to ensure the most correct operation of the mechanism, and the structure itself can be fastened with clamps or carriages. In any case, the effective operation of the mechanism is ensured only without a direct strong load on it at the very moment of switching.
Rear external shift mechanism
The operation of this design is completely similar to the one described above, with the difference only in a greater number of involved stars. It also has a moving frame that simultaneously provides the necessary tension for the chain and prevents it from jumping in the other direction.
This bicycle gearshift mechanism also has certain parameters, according to which you should choose the appropriate option. Pay attention to:
- type of attachment to the bike;
- shift cable pitch;
- the difference in the diameter of the stars;
- thrust type.
It is interesting that the diameter of the largest sprocket in this case will always be the same, and the choice of all the listed parameters should be based not on personal preference, but on the ideal one for a particular bicycle model.
Pros and cons of an external system
Among the positive aspects of the design under consideration, many distinguish simplicity, low cost, compact dimensions and, with all this, a large number of shifted gears. Of course, external gear shifting on a bicycle has no less cons.
- high probability of breakage if dropped;
- switching only when driving;
- frequent chain wear;
- high degree of influence of external factors on work.
This mechanism is rarely found on mountain riding models, but is often applicable to city bikes. It is based on the work of the planetary hub, which is located at the back and contains the entire mechanism for shifting. Thanks to this design, only one chainring in the front and one in the back can be seen on the outer casing of the bike. The number of speeds of this design is also quite large. In addition, a brake mechanism is mounted in the structure.
Pros and cons of the internal system
In comparison with the external design, this gear change on a bicycle can be carried out even when the pedal transport is completely stopped. Also, all working parts are inside the bushing, which means they are protected from external factors, durable and reliable. The built-in brake and ease of operation are also among the advantages of the system, but there are also disadvantages. Among them are the large weight of the mechanism, the impossibility of self-repair on the road and the difficulty of movement when the nodes friction.
It makes no sense to describe it in detail, since such a mechanism has collected in itself all the disadvantages of both of the above structures. You can only meet it on city bikes, and it is a hybrid of a hub and a conventional external design.
The principle of the mechanism
The bike model with the ability to switch speeds is most often equipped with a pair or three stars in front, called leading, and several times more stars in the back, called driven. The chainrings are located so that the smallest chainring is closest to the bike’s body and is considered first. The rear stars, on the contrary, are numbered from the largest one, which is closest to the frame. Correct gear shifting on a bicycle should be carried out according to a certain scheme, which will not allow the chain to be too skewed, which leads to a quick breakdown of the entire mechanism.
So, for example, on a bike with three stars in front and nine in the rear, the switching will be as follows:
- The front large chainring will be used in a chain from the rear number 7, 8 or 9, provided that you are driving on a smooth track without obstacles.
- The middle chainring distributes the load along with the number 4, 5 or 6 driven chainrings for driving on country roads, uneven asphalt, wind in the face or other obstacles.
- The third drive sprocket is paired with rear chainrings 1, 2 or 3 for comfortable riding on rough terrain, uphill and other tough obstacles.
To make gear shifting on a bicycle as comfortable as possible, it is not enough to take into account the degree of cross-country ability. The main criterion for choosing a gear is the cadence, which should ideally be 80-110 revolutions per minute. Only at a given rotational speed, the ride will always be comfortable and not too tiring, therefore, it is undesirable to start immediately at high speeds.
To extend the life of your bike’s drivetrain, remember that the main working sprocket at the front is the middle sprocket, as it prevents the chain from skewing significantly while driving. Any throwing of the chain over the sprockets is completely controlled by the cyclist. In this case, the correct algorithm for paired operation, described in the example above, must be observed.
Rules for cycling with gear shifting
First of all, this is a careful handling of the entire mechanism. The chain must not be too skewed during operation and must not have a minimum rotating load during shifting. In addition, any changeover should be done gradually. You should not “jump” immediately from the first to the last gear, so it is better to switch in advance before entering the mountain.
In fact, adjusting the gearshift on a bicycle is not too difficult for a cyclist and can be done on your own. The need for this procedure is the presence of malfunctions during gear shifting or in general the impossibility to change the speed. In any case, work should be started by setting up the rear mechanism. Let’s consider everything in order.
Rear derailleur setting
Before adjusting the gear shift on a bicycle, inspect the structure and make sure it is intact. High-quality adjustment can only be made if the chain tensioner is located strictly parallel to the cassette stars.
Tuning begins with setting the chain in place to travel at the fastest speed, that is, on the smallest star. After that, adjustment occurs by tightening the screws near the chain itself. The top screw should be screwed in so that its shift roller is aligned with the small sprocket, and the lower screw should align the pulley with the large sprocket. Now you need to pull the bicycle gearshift cable and place it in the groove near the fixing bolt, which is then tightened. It remains only to check the quality of the work done by shifting gears and dropping speeds. If the speeds turn on poorly, then the tension of the cable must be slightly loosened, but with a different adjusting mechanism at the very fastening of the cable. In case of poor speed drop, the cable should, on the contrary, be tightened tighter.
After all that has been done, it remains only to ensure the smooth operation of the entire structure, which is done when the chain is installed on a large star in the back and on a small one in front. With this arrangement of the mechanism parts, the chain should be pulled so that the upper roller is as close as possible to the star, but does not touch it. A similar work needs to be done by setting the chain in the opposite position. on the small star in the back and on the large one in front. The degree of tension is regulated by a special screw, which is above all others.
Front derailleur setting
Before setting up the gear shifting on the bike, here you should also make sure that the entire mechanism is correctly and securely attached to the bike frame. After that, set the minimum speed and loosen the cable by adjusting the distance between the frame and the chain by moving the right screw. The ideal clearance is a distance of one millimeter, after reaching which the cable must be fixed in a special recess near the bolt. Similar actions are carried out when setting the maximum speed, only by adjusting the left bolt. After all the manipulations, the work must be tested and, if necessary, the cable tension must be loosened. Such situations arise with poor switching to small stars. Otherwise, with a poor transition to large stars, the cable will need to be tightened more.
Based on all of the above, it will not be difficult to independently adjust the gear change on a bicycle, even for a beginner, especially since every cyclist has the necessary tools for this.
The scheme of operation of switching speeds involves throwing a chain. After the shifter has been pulled, you need to turn the pedal, only after that the chain will move to another star. Extraneous sounds and clicks when switching may indicate that a changeover setting is needed.
Why the speed may not switch:
- the chain or cassette is worn out;
- the cock bent;
- switch backlash;
- the presence of damage to the cables and shirts;
- the switch has not been adjusted or the previous setting has been lost;
- the transfer cable is damaged (it may stretch, break or be close to breaking);
- broken switch;
- broken spring in the switch;
- the teeth of the rollers are ground off;
- the chain is dirty, which prevents it from rolling freely.
Therefore, if problems with switching occur, it is necessary to carefully check each of the possible causes of failure. In most cases, the reason lies in the lack of regulation or the fault of pollution. Parts can only wear out with long-term and intensive use.
Fixing the problem
The method of correcting the problem that has arisen will be determined depending on the cause of the breakdown.
Cables and shirts
One of the most common problems that amateur cyclists face is cable wear. To check the condition of the cables, you need to find areas without a shirt, and then click the shifter. This will allow you to see the inside of the cable, which should not have emerging threads. The presence of such defects indicates that it is time to change the cable.
Another important detail is the aluminum cap. This is an obligatory part of the cable that protects it from loosening. If it is damaged, then it must be replaced.
If the gears are shifted, but not always as the cyclist requires, then the problem may be in the shifting rollers or cassettes, where the teeth have worn out. The only way out of this situation is to buy a new part.
The chain becomes unusable approximately every 100 kilometers. Although the chain can be used after such a distance, it will no longer perform all tasks properly. Therefore, cyclists often have multiple spare chains.
Using new chains will allow the cassette to last longer as the worn part will not affect the rest of the bike. The “gauge” tool is used to determine the state of the chain.
An even cock is the key to high-quality gear shifting in your bike. If it is bent, then there are two options: bend it or buy a new one. In any case, until this part becomes even, it makes no sense to even try to adjust the gears on the bike, since the idea will be unsuccessful due to damage to the system.
One of the most unnecessary accessories for cyclists is a rooster guard. Such a detail can be found without any problems in any city. But if the protection works and the part itself remains intact, and the frame cracks because of this, then the one who bought such a device will incur high costs.
Setting the switches
Derailleurs on a bike are divided into front and rear. It is the rear ones that are most damaged when driving, so it is recommended to adjust them first. The process itself will be long, as there are more stars than in the front derailleur.
Rear derailleur setting:
- The screw “H” must be tightened so that it aligns with the small sprocket.
- Screw “L” must be tightened so that it is in line with the large star.
- You need to set the highest speed on the shifter.
- The cable is stretched and fixed.
- If, after the performed manipulations, high gears are turned on with interference, then the cable must be loosened. If the situation is the opposite (the gears are badly thrown off), then the cable must be pulled.
The basic configuration steps are now complete. The cyclist only needs to adjust the shifting accuracy. The procedure will get more complicated depending on the number of stars used. The chain is installed on the stars as follows: in front. on the smallest, on the back. on the largest. After that, the tension screw is tightened until the roller is as close as possible to the cassette. It should not rub against the cassette. A similar procedure is carried out with the chain, which is then installed on the largest chainring and the smallest rear chainring.
Front derailleur setting:
- Check the correctness and tightness of the fastening.
- Release tension at minimum speed.
- The screw “L” must be tightened so that a gap of 1 mm is created between the body and the chain.
- Fasten the cable with the bolt.
- Repeat the same procedure with screw “H”, but then the tension is set to the maximum speed.
You will need to adjust the speeds until the chain begins to smoothly and freely change from one speed to another. If, when changing the speed, problems begin (difficult move, the chain flies, and so on), then the cable is tensioned using the adjusting bolt to the desired position.
After the manipulations with the settings are completed, the system is checked using a race, where the recommended gear ratios will be used. Adjustment is a standard procedure on any speed bike, as the tension in the cables will loosen over time. Therefore, setting speeds is often a planned activity that does not require replacement of parts.
You should not ride your bike at speeds at which there is a strong skew, 1/8, 3/1, and so on. Recommended speeds for stars depend on size:
- small. 1 to 4;
- medium. 3 to 7;
- large. from 7.
The incompatibility of the gear and the sprocket will lead to the chain sticking and spinning, which will cause the part to wear out an order of magnitude faster.
Most modern adult bicycles are equipped with a system that allows you to adjust the pedal load and the effort the cyclist spends on moving on different types of surfaces at different speeds. Many novice cyclists are interested in the answer to the question of how to change gears. Choosing the right choice will increase your riding pleasure and keep your bike running for longer.
Gear shifting is carried out by fixing the chain on the stars of different diameters, which makes it possible to pedal the bicycle with different frequencies, while the speed of movement in different conditions may vary. In classic bike design, there are two types of chainrings: chainrings and rear chainrings. Usually, there are 2 or 3 stars in the front, and from 7 to 10. Choosing the right ratio of stars helps to protect the bike mechanisms from premature wear, so you need to find out the answer to the question of which combination of stars will be optimal for shifting.
When changing the speeds on the bike, you need to remember that it is highly discouraged to simultaneously use the stars on opposite sides of their size ranges, i.e.: 1 in front and 7-8 behind, 3 in front and 1-3 behind, as well as 2 in front and 1-2 and 7-8 behind. This will cause the chain to skew and lead to faster chain failure. How should you proceed? The exact answer is as follows: for 1 star in front, you need to choose respectively 1-2 at the back, for 2 in front. 3-5 at the rear, for 3 in front. 6-8 at the back. This classification is approximate, and is given in order to explain the general principle to be followed. You need to accurately determine the combination based on the number of stars on a particular bike.
You need to switch speeds following the basic general recommendations:
- You can change the mode only while driving, i.e. then when you pedal.
Try to find the right moment to change the speed. This should not be done while driving uphill, against the wind, or on an extremely uneven surface. i.e. when the chain is under increased stress. Wrong timing can lead to serious damage.
The mechanism should not be changed more than one step at once.
First move the chain one sprocket to the front and then one or two to the back. You can also try to turn on the rear sprockets first, and select the front sprockets for them, however, the chain must not be twisted.
Wait for the moment when the mechanism gives an “answer”, and when you feel that the chain has shifted, you can repeat the procedure.
Pedaling too hard and too slow can injure the knee joints, and too frequent and light pedaling will be a waste of energy. The average number of revolutions for cross-country driving is 70-90 rpm, but you need to choose the number that is right for you. so focus on your own feelings.
Finding out the answer to the question of how to change gears on a bicycle while riding, and choosing the right moment for this, you will maintain the performance of your bike at the proper level for a long time, and make your trips more productive and safe.
Bicycle gear shifting
Any cyclist should know how to properly switch speeds on a bicycle. When they buy a bicycle for children, they are always interested in how many speeds it has. And the higher the number of speeds, the better. But experienced cyclists know that the speed of a bicycle depends on the rider, or rather, on the work of his muscles. And the art of competently switching gears is the quality of cunning professionals, which allows you to squeeze the maximum possible resources out of the car in rough terrain.
It used to be simple: the road bike had one speed. Therefore, on the plain, everything depended on the skills of the cyclist himself, and to ride in mountainous terrain, he had to adapt to the terrain conditions: while riding downhill, the cyclist accelerates the car as much as possible in order to drive up the next mountain by inertia. If the ascent is protracted, then the cyclist rides uphill until he can pedal. Then he dismounts the bike and proudly walks alongside to the top to continue the journey down again.
Modern bicycles have two sets of gears. front (sprocket) and rear (driven sprocket). It is extremely important to learn how to choose the right gear depending on the nature of the ride. First, you need to learn a few simple rules for gear shifting:
- There is no need to change gears when the bike is stationary. This can damage the switches.
- You should change gears even before your speed drops in front of difficult-to-pass areas (for example, sand or loose snow) or on the rise.
- You don’t have to pedal hard when changing gears. Switching is easiest if no load is applied to the circuit and there is a speed margin.
- When switching, you need to ensure that the chain is not strongly skewed. That is, you should not use a large chainring and a large rear sprocket. In reality, you should use the following gears: with a small star in front to 4-5 stars in the back, from the second front. from 3rd (2nd) to 6th (7th), and with a large front. from 5th to last 8- (9).th.
Now let’s talk about choosing stars. It is impossible in advance to accurately match a particular gear to specific road conditions. Of course there are many formulas, graphs and tables, but most of them are calculated for road bikes, fair weather and smooth asphalt. Should the conditions change, and all the calculations are down the drain. The choice of gear depends on the road or lack of it, the slope of the track, temperature, ground conditions, tire pressure, wind, the rider’s physical condition, adrenaline and blood sugar levels. There are other criteria that cyclists can use as a guide. One of them is cadence. It is known that the optimal cadence when driving on a horizontal surface. for example, on road bikes. averages 95.115 rpm, while for cross-country riders this value will already be 70.90 rpm. But for amateurs and cyclists, this is just a guideline, not a rule. There is no need to try to start immediately from high gears, first in low gears we warm up the muscles, unwinding to optimal gears. When choosing a gear, as in any business, the cyclist needs to stick to the “golden mean”, and not go to extremes. A slow pace of driving in large gears is very detrimental to the condition of the knee joints. Pedaling too often will reduce driving efficiency and cause fatigue faster. In difficult road conditions (driving on mud, sand, grass or snow), the gears are lowered due to the fact that the torque reserve is required. The technical capabilities of the switches do not always allow the chain to be dramatically shifted from small to large stars. For mountain hikes with backpacks, a set of chainrings, e.g. 48, 38 and 28 teeth, is usually sufficient.
When driving against the wind or uphill, you need to switch to “lower gears” close to 1: 1). This set of gears increases cadence but decreases speed. When driving on flat terrain, the gear ratio can be 4: 1 to maintain speed. In a motorcycle race, a speed of over 100 km / h can be achieved. In these record-breaking rides, cyclists use a gear ratio of 8: 1 or more. Usually, however, the muscle strength of the legs is not enough to spin such gears from a place. Even athletes do not use gears greater than 5: 1, but rather increase their cadence.
In 1985, in the United States, John Howard set a speed record of 245.077 km / h. For the first time he covered 241 kilometers on a bicycle in one hour. Just ten years later, Rompelberg Fred from the Netherlands broke his world bicycle speed record with a result of 269 km / h.
Many novice cyclists avoid frequent gear changes and even when riding upwind, leave the chain on the large drive and small driven gears. Their ride is more like the maneuvers of a sailboat against the wind. As a result, after such a ride, knee pain can naturally occur. Meanwhile, a competent cyclist when riding upwind, having reduced the gear ratio to 2-3: 1, will be able to maintain a higher speed with less effort. In small gears, pedal at 80-90 rpm.
Thus, some recommendations can be made:
- At the beginning of the season, it is recommended to drive at least 200-300 km in low gears and with a high pedaling frequency.
- It is better to start the morning “rolling in” with lower gears for 15-20 minutes.
- Long-term cycling is aided by an even cadence at a comfortable pace for the cyclist. With the right gear selection, this can be achieved even on a hilly track.