Chain Does Not Shift On Bicycle

Poor cycling gear shifting. How to properly adjust the rear and front derailleurs on a bicycle: photo and description of the process

Despite the fact that the bicycle was invented a long time ago and, it would seem, should have been out of date for a long time, but this two-wheeled vehicle is gaining more and more popularity every year. Cycling enthusiasts prefer this type of transport due to its convenience, ease of operation, environmental safety and practicality. Not only ordinary bicycles are very popular, but also mountain, track bikes, which use modern innovative technologies. In order for the owners to enjoy cycling, they need to take care of it and monitor the condition of all parts and assemblies. If, in the process of cycling, you hear extraneous sounds, creaking, knocking and twitching during gear changes, it’s time to pay attention to such a detail as the gear selector.

Rear derailleur

The gear shifter is an important part of a multi-speed bike. Thanks to this component, it becomes possible to move in extreme conditions, which include upwind movement, ascents, poor road quality. The transmission unit must deal with all these problems. The quality of the ride and the safety of the cyclist depend on the smooth operation of the speed switch. This skill is very useful, and every bike owner should learn how to independently adjust the gear shifter. Every cyclist can make adjustments to bicycle shifters. You need to study the theory in detail by reading the instructions, or using the advice of experienced bike owners.

Before setting the derailleur, the rear derailleur must be adjusted. Placing the bike in the correct position (wheels up) will greatly facilitate the entire adjustment process. So, all the necessary details will be in sight, and it will be much easier to get to them.

chain, does, shift, bicycle

Reasons for poor gear shifting:

  • physical defects of the switch parts;
  • contamination of parts. To prevent this from happening, the components of the transmission unit must be periodically cleaned of dirt, dust and old grease;
  • worn out cable with elements of damage. Such a part requires replacement;
  • damage to the cock.

If you observe damage, deformation and wear of the constituent parts, they must be replaced as they are practically irreparable.

If all parts are OK, adjust the switch. What does the speed switch consist of? The components of the speed switch are as follows:

  • Handle for gear shifting located on the steering wheel;
  • A shifter that attaches to the handlebars near the handles. Handles and a cable are attached to the shifter. It is with the participation of the cable that the impulse is transmitted from the shifter to the stars;
  • Cassette, which includes stars of different sizes;
  • front fixing mount;
  • rear derailleur, whose main function is to switch the chain to the required sprockets.

How the switches work

Using the handle and shifter, the cyclist activates the required speed. In a certain position of the handle, the cable is pulled. As a result of this tension, the frame is thrown onto larger sprockets; when the cable is loosened, it is not thrown onto small sprockets. As mentioned above, bike setup can be started from the rear derailleur. Procedure for adjusting the rear derailleur:

  • select the second star in the front block, and the smallest in the rear one and set the switch chain on them;
  • The bike’s rear derailleur system has two bolts that act as stops. One is abbreviated as H, and on the other. L. These two bolts are used to adjust the high and low gears on the stars. If during the adjustment process any extraneous sounds occur, you can get rid of them using the latch;
  • check the tension of the cable and, if the tension is not correct, use the regulator located on the shifter;
  • Test the switching quality. If the switching occurs smoothly, no extraneous sounds are heard, then you did everything right.

What to do if you can’t adjust the bike’s rear derailleur

There are several methods for solving this issue. But if the standard tuning instruction did not work, to tune the rear derailleur you need to:

  • dismantle the chain, remove the cable;
  • move the switch to the chain position to the smallest star;
  • use adjusting bolts (this way you can tighten the cable);
  • set the adjusting bolt H to the extreme position;
  • move the part called the parallelogram to the big star and adjust the position of the bolt L.

The regulator is fixed with screws. It must be set to the extreme position. After that, the chain must be displaced in this order: the front cassette is the largest star in diameter, the rear, on the contrary, is the smallest.

Bicycle front derailleur

The transition to setting this mechanism is possible only when the rear derailleur is set. This feature is important to take into account before starting work. The figure shows the switch (round, black).

Leave the chain on the middle sprocket of the front block and place it on the large sprocket in the rear block. If chain friction is observed, re-engage adjuster L. To adjust stop H, the chain moves to the largest sprocket at the front and smallest at the back. The adjuster will help you position the chain in the optimal position without friction and excessive chain tension. At the end of the work, be sure to check the quality of its implementation.

Correct installation of the front derailleur

You can start the front derailleur setting only after adjusting the rear derailleur. Installation is the initial step in adjusting the speed switch. It’s very important to do it right.

  • before installing the switch, it is necessary to inspect the condition of the constituent parts and, if necessary, clean them of dirt and lubricate.
  • Next, adjust the location of the front derailleur. On the frame, it should be located along the pipe under the saddle.
  • Set the steering angle parallel to the drive sprocket on the front cassette of the transmission unit.
  • Next, you need to adjust the gap between the underside of the derailleur frame and the top line of the teeth of the large gear. The gap should be minimal.
  • Adjust the degree of cable tension.
  • Place the chain close to the inside of the frame.

It is also worth paying attention to setting up the chain. The bicycle chain is a very important element, with the help of which the impulse is transmitted from one chainring to another and the adjustment process takes place. The technical condition of the circuit is of great importance for the operation of the entire system. If, for some reason, the bicycle chain is stretched or deformed, this cannot but adversely affect the operation of the entire transmission unit. To prevent this from happening, the chain must be periodically removed and cleaned, and then set the correct position. There are lock and lockless models of bicycle chains. They differ in the way they are connected. To remove the locking chain, it is enough to find the link with the lock and disconnect it with a screwdriver. The lockless bicycle chain is disconnected using a squeeze. This tool helps to push the link axle out and make the connector. If it skews for some reason, this can adversely affect the gearshift process.

One of the best manufacturers of bicycle parts, including derailleurs, is the Japanese company Shimano, which has a proven track record of producing products in which Japanese quality is combined with budget and price. Shimano derailleurs (fig. 3) are suitable for all types of bicycles. Shimano derailleurs are installed on both regular touring bicycles and mountain and track bikes with gearboxes up to 33 speeds.

Another recognized market leader is Sram. The products of this company are used on bicycles of the city bike category, as well as on sports bicycles. Sram products are of good quality and affordable price for cycling enthusiasts.

Every bicycle owner who prefers this type of transport to others is obliged to understand how to switch its speeds. It is believed that the more speeds a bike has, the better it is. But in fact, speed only allows you to improve the quality of maneuvering and squeeze the maximum out of the bike’s capabilities, so then everything depends on the dynamic efforts of the person riding the bike. Conventional bicycles have a simpler design compared to high-speed ones. There is less hassle with such a bike, but it also has fewer possibilities. In the transmission unit of such bicycles there are only two stars: one large and one small. Multi-speed bicycles, which have gained popularity in recent years, have two sets of sprockets in their transmission units: front and rear. Each cassette contains stars of different sizes. To switch gears correctly, you need to remember a few basic rules:

  • If your bike is not equipped with a planetary hub, you only need to switch gears on it while driving, otherwise there is a danger of damage to the bike.
  • During gear shifting, it is not necessary to apply significant dynamic forces, in order to eliminate the danger of a burst of flowers, it is advisable to change gears sequentially, without making sudden jerks.

Why gear shifts poorly on a bike

On entry-level bicycles, the transmission of the cheapest groups is installed, and when the gears start to shift poorly and jam, the owners just shrug their shoulders. what, they say, you can take from cheap rubbish.

A big surprise befalls those who buy a much more expensive bike, and after a while again encounter shifting problems. The point here, of course, is not karma, but the wrong attitude to technology.

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I am by no means claiming that there is no difference between starter and top-end components. Of course, the experienced cyclist with eyes closed will distinguish the Shimano Alivio from the XTR in three clicks.

But the reasons for the fuzzy operation of the transmission do not so much depend on the class of the transmission, but on its condition and settings. In this post, I will not talk about how to configure the switches, for this a separate article will be released soon, subscribe, and I will send you a notification about its publication.

Causes of fuzzy operation of gear switches

Cables and shirts. This is the most common problem, especially for beginner cyclists. I just wonder what a terrible condition some cyclists are in.

At the end of the cable, there must be an aluminum cap that protects it from fluffing. With pliers, you can carefully remove it and unscrew the bolt securing the cable to the rear derailleur.

Release the jacket from the stops by carefully removing it from the cable. The cable itself can be left in its slot in the shifter. When he is completely naked, once again inspect for raised threads and scuffs. Spray WD40 on a rag and wipe it thoroughly.

The shirts, if they are in order, can also be used a second time. Fill them with more WD40, and gently rub there with a cable. The task is to drive out all the dirt that has accumulated during the riding period.

Here I ask you to take into account the following thing. cables and shirts do not need lubrication. Never lubricate them with thick greases, such as grease. Literally after a few trips on the ground, you will have a consistency in your shirts, consisting mainly of dirt.

If you need to calm the soul, then spray with Teflon spray, it dries quickly, but leaves a thin gliding layer. Which, however, will be erased after a dozen switches.

One more point. There are Teflon-coated cables, such as Shimano XTR Cable, which cost quite a lot of money. In the days of fetishism, I used only these, because of the sliding cover, the effort on the shifter is slightly less.

Unfortunately, after about a year of active skating, Teflon in places of friction is completely erased. However, these cables have a very big advantage. they come with spout stops, which effectively prevent dirt from getting in.

Returning to shirts, make sure that nowhere are too long, or vice versa, short sections, because of this, there will be increased friction in the bending places, and sooner or later dirt will accumulate there.

The bent cock. If you do not know what this part is, then here you can read a note about a bicycle cock. Sometimes it happens that a seemingly perfectly tuned rear derailleur does not work clearly, despite fresh cables and shirts.

The reason may be that during transportation, the bicycle is clamped somewhere, and the cock bent slightly. If you cannot achieve a clear gear change, then remove the cock and put it on the table.

If it is slightly crooked, then you need to bend it. Do not overdo it, aluminum can give microcracks. How exactly to bend it. I will not advise. I do it in an artisanal way. I put it on the bike and pull it with my hands. Ideally, you need to edit with a special typewriter, which even takes into account the asymmetry of the dropouts.

Rear derailleur play. Move the rear derailleur towards you and away from you, keeping where the cable goes. Ideally, there should be no backlash at all, but a small free play does not represent anything criminal, especially on the initial transmission groups.

During operation, this backlash tends to increase, and then delays in switching, fuzziness, etc. begin. If everything is in order with the ropes and the rooster, then with fine tuning you can overcome the negative effect of backlash.

Most often, the reason that the bike shifts poorly is a complex of problems. Dirt in shirts, a slightly bent cock, a slight backlash in the switch, poor tuning. all tolerances add up.

over, many Catalans drive like this, and find it normal when the speeds are switched on the principle of three forward, two back. Guys, this is not normal!

Any drivetrain, even the lowest Shimano Tourney, needs to work well. Do not get used to the bad, otherwise even buying an expensive bike, after a season or two you will get the same.

Friends, on my site there is still a lot of useful information about bicycles and travel. I suggest that you receive email notifications about the publication of my new articles, so you will always know that I have written something new. Follow the link please.

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How to adjust the speed switch on a bike

It often happens that either the speeds on the bike are not switched clearly, or some new transmission elements have been installed. In this case, you will need to adjust the speed switch and it is quite possible to do this work on your own, without contacting specialized workshops.

Necessary terminology

To understand the process of self-adjusting the speed switch, you need to know the definition of some specific terms, otherwise it will be difficult to understand the instructions.

Things to remember:

  • Speed ​​switch (override). This is a transmission element that is specifically responsible for gear shifting. If there is a rear overhang, then it also acts as a support for the tension of the bicycle chain. The crossover (back and front) can be described as follows: it is a parallelogram mechanism equipped with a powerful return spring, on which the frame is fixed. The rear derailleur has two rollers inside the frame. if the level of cable tension rises, the frame shifts the chain to large stars, and if this cable tension decreases, then the chain is shifted towards small stars with the help of the frame. The mechanism of the front derailleur works in the same way.
  • Shifter. It is designed to switch speeds by changing the tension level of the cable. Most often, the shifter is located on the handlebars, but in some bicycle models it can also be located on the lower tube of the frame triangle. Note:shifters and speed switches have a common connection on the steering wheel (this is provided by a cable) and are covered with a jacket.
  • Cassette. This is the name of the rear transmission unit, which consists of stars of different sizes (of different diameters and with a different number of teeth) and is installed on the rear hub drum. If the bike model is old, then a ratchet is used instead of a drum in the rear hub.
  • Cock. This is a metal part that helps to maintain the integrity of the frame and rear derailleur in the event that the vehicle has been hit. The rooster is always attached to the frame, and a cross-over is already attached to this metal part. When a blow occurs, it is this very cock that breaks down, and the frame and the speed switch (crossover) remain intact.
  • System. This is the name of the front transmission unit, which consists of stars of different diameters and with a different number of teeth. These stars are fastened to each other and the connecting rods with special hollow bolts on the connecting rods, but you need to know that there are no hollow bolts in cheap bicycles. the stars and connecting rods are riveted together.

Why is there a violation of gear shifting

To understand what action should be taken to adjust gear shifting, you need to understand what causes may lead to the problem under consideration. Experts identify several such predisposing factors:

  • deformation of the rooster;
  • stretching the cable;
  • deformation of the speed switch;
  • malfunctioning return spring.

How to fix defects

The speed switch will work perfectly and the bike itself will be with a new (or not very old) cable, with absolutely intact shirts (and not dry!) ​​And not deformed (or in a small volume) stars and chain.

If the cable is just stretched, then you just need to pull it up. But if the cable breaks, then you cannot do without replacing this element. The process of replacing the cable is not difficult, the main thing is to strictly adhere to the recommendations of specialists:

  • unscrew the cable fixing screw, which is located on the cross-over;
  • pull the cable out of the shirts;
  • if necessary, disassemble the shifter and pull the cable out of it;
  • a new cable must be inserted into a special groove in the shifter, and it is the metal tip of the cable that must enter into the groove;
  • lubricate the entire cable with a special grease, you do not need to spare the consumable;
  • pass the cable through the shirts;
  • there are special grooves on the frame, into which shirts are tucked;
  • fasten the cable with a screw on the front.

In case of poor gear shifting, pay attention to the return spring. it must be clean and lubricated. To achieve this, you just need to rinse the spring under running water, dry it completely and lubricate it thoroughly.

If the frame of the rear derailleur is crooked, then this can only mean one thing. the cock is bent. If this is not critical, then you can correct the cock with your hands. you need to take the rear switch in your hand, which is fixed on the cock, and with the other hand hold the frame. Slowly pull out the problematic transmission element (rooster) until relatively level.

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Note: this “repair” of the cock is a temporary solution to the problem of shifting gears. The fact is that the rooster is a consumable that needs to be changed in time, and not constantly repaired / pulled.

In some cases, the bike owner pays attention to a deformed rear derailleur (the front derailleur rarely suffers on impact). it can also be returned to its original position using the hands. But if the rear derailleur is deformed too much, then it is advisable to replace it.

Note: After performing specific manipulations to repair bent / deformed parts, you should not use the bike for too long. this may end in a fall, another breakdown at the most inopportune moments. And in some cases, such carelessness can lead to a road accident.!

How to properly adjust the rear derailleur

To independently adjust the rear derailleur on a bicycle, you just need to strictly follow the step-by-step instructions from experts in this process. So, follow all the steps:

  • Move the chain to the small sprocket with the right shifter.
  • Unscrew the fixing screw and release the cable.
  • Find the screw with the “H” mark. Use a screwdriver to adjust this screw so that the smallest star lies in the same plane with the rollers, which are located in the foot (frame).
  • Pull the cable by hand and fix it with the screw.
  • Check the operation of the switch, and if it does not work correctly, the chain does not switch well to large stars, then you need to tighten the cable harder (either with the help of a drum or with a switch).
  • Move the chain to the largest sprocket available in the cassette.
  • Find the screw marked “L” and adjust it so that the tab (frame) and the sprocket are in the same plane. in this case, the crossover will not be able to get into the spokes of the front wheel.

How to adjust the front derailleur

There are also clear and simple step-by-step instructions for adjusting the front derailleur:

  • Move the chain to a smaller star.
  • Unscrew the fixing screw and release the cable.
  • We find a screw marked “L”, with its help we adjust the position of the frame so that the chain is between the plates of the frame, but at the same time does not touch them.
  • We stretch the cable, fix it with a screw.
  • Now we move the chain in the cassette to a smaller sprocket. it is convenient to do this using the rear derailleur.
  • With the front derailleur, move the chain to the middle sprocket and look. if the chain on the second one touches the outer side of the frame everywhere, then you need to increase the tension of the cable using the drum located on the left shifter.
  • We switch the gear to the largest sprocket in the cassette and check. if the chain touches the walls of the frame, you need to move the last element so that the chain is in the middle. This manipulation can be done using the screw marked “H”.

Bicycle Speed ​​Switch Adjustment Instructions

Usually, advanced cyclists change the derailleurs to fit their bike exactly the equipment they want, thus making the bike fit to their needs. Beginners usually do not have to think about such an acquisition, unless a breakdown has occurred. Nevertheless, it will be useful to consider popular models.

The first models were invented in the 50s. Basically, the gear system is the front chainring. The chain is thrown from one chainring to another, increasing or decreasing the cadence.

  • Fast pedaling at low speed. low gear. Combination of large front and back stars. It is designed to overcome mountains, off-road and similar areas.
  • Increased for high speeds. It is a large star in the front and a small one in the back.

Switching takes place using a derailer:

  • The rudder coins pull the cable.
  • The frame shifts and throws the chain onto an adjacent star.
  • Behind everything is the same. The patch moves from the tension of the cable and throws the chain.

Now you know how it works. There are two main product manufacturing companies:

On the steering wheel, the gears are measured using coins:

  • A switch combined with a handle. To change the speed, you just need to turn the drum to the desired mark indicating the gear. They are easy to use, which is why they are often used on children’s and women’s models.
  • Triggers. They control the change in the position of the cable using two levers. Can be combined with a brake lever, or can be installed separately. This combination is usually found on advanced models with a hydraulic braking system.
  • There are high class combination handles. Such a brake lever can be shifted from left to right, thus changing the gear. Analogs have been around for a long time on road bikes.

Speed ​​selector adjustment

However, there are some peculiarities:

  • First you need to adjust the position of the front derailleur relative to the frame. You need to slightly loosen the so-called adjusting screw and set the frame horizontally. This frame must be parallel to the chain.
  • The next step is to set the required front derailleur height. It is recommended to set the gap between the edge of the frame and the teeth of no more than 2 mm. This indicator is largely responsible for the quality of gear shifting.
  • With the front derailleur bezel correctly positioned in both planes, secure the screw.
  • After that, you need to install the chain on the largest chainring in the back and the smallest in the front.
  • Use the screw to release the cable. Turn until it stops, and then unscrew the so-called adjusting drum one turn.
  • Now you need to set the frame in such a position relative to the chain so that the inner side of the frame is removed by 1–2 mm.
  • Pull the cable slightly and fix the screw.
  • Now the big star of the system needs to be installed the chain.
  • Use special screw H for adjustment.
  • Check the quality of the setting.

Rear derailleur

You will need a hex wrench and a screwdriver. Place the chain over the largest sprocket in the front. At the back we put the chain on the smallest star. This is done using the speed switch, even if the settings are knocked down.

The cable on the switch is fixed with screws, which must be loosened as much as possible. There is a “drum” on the coins. It must be screwed in until it stops. And then turn it back a few turns. Rotation pulls or lowers the cable. Thus, the micro-adjustments of the switch are made. But now we are not adjusting anything, but creating the necessary range for future settings.

Find the screw H on the switch. It must be signed. Turning this screw adjusts the position of the derailleur tensioner rollers relative to the small sprocket.

Your task is to match the tensioner roller clearly opposite the small asterisk.

Now tighten the cable and fix the screw. You don’t need to pull very hard. It is necessary that the cable simply straighten out and be elastic. But it’s better to fix it as it should.

Now we throw the chain onto the largest star in the back. So far, the gears may be shifting incorrectly, because the settings are not completely finished. Don’t be scared.

At the front, the chain should be on the smallest star. And the sequence of actions is repeated. Only this time you need to adjust the position of the tensioner rollers relative to the large sprocket using the screw L. Its movement may be less noticeable, so be careful.

Now check the quality of the settings. Maybe indistinctness. To eliminate it, you need to make a few clicks with the drum. Now let’s check again the same positions where the fuzziness was.

And you also need to check the bike on the go. And to correct the indistinctness with the drum clicks. Practice will help you.

Front derailleur

To adjust, you need a hex wrench and a Phillips screwdriver.

  • We put the chain on the big star at the back. Small in front.
  • Loosen the fixing screw. The position of the frame is adjusted with a screw marked LOW. Our task is to set the gap between the chain and the left side of the frame at about 0.5 mm.
  • Now we fix the cable. It is not necessary to tighten too much. Switch to a small star in the back and a large one in front. There may be interruptions. As long as it’s ok.
  • Using the screw, set the gap between the chain and the right side of the switch frame to 0.5 mm.
  • Checking the quality of the settings. If the chain is thrown with an interference, then carry out micro-adjustments. Make no more than 1-2 turns so as not to lose the settings. Done.

Reasons for incorrect gear shifting

Many people may face some difficulties when setting switches. First, a little theory. The front derailleur does not work by itself. It works in conjunction with the stars of the system.

The stars have special nodules that are designed to make the chain switch better. The quality of switching directly depends on the state of these “pins”. If they wear out or wear out, then the switching will accordingly suffer very much.

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The front derailleur itself consists of the following components:

The frame comes in different thicknesses. Internal width depends on chain width.

  • You also need to pay attention to backlash.

How to fix defects

The rooster is the bracket to which the switch is attached. This is an inherently weak link, because when the switch hits the ground, it is this component that will be damaged, and the frame will remain intact, which is much more important.

By the way, there are switches that are attached to the hub axle. The mechanical strength of the system is higher, but this only applies to extreme equipment.

Titanium frames are made with fixed roosters, since the material itself is strong. Interestingly, in English it sounds like Derailleur hangar. We have stuck the name “ cock ” because of the comb at the end.

Detachable shanks are mounted on carbon and aluminum frames. This component is cast from a large carbon aluminum alloy. Durability is low.

If the cock is bent, then it is better not to straighten it. It will crack anyway.

Roosters have different geometry. Please be careful before purchasing. On cycling trips, participants take extra roosters with them. And usually one bike is enough for two. They don’t break very often.

By the way, if the rooster is still broken, but you want to ride, then you can make a single speed:

  • To do this, take a squeeze.
  • We press out one of the pins. It doesn’t have to be a connector pin. He is thicker than the others. You must press out the pin in such a way that it does not fall out, but remains in the link. It is best to unwind not to the end and check how much the pin came out.
  • Now we shorten the chain to the desired size. It is better to move the rear wheel forward in advance. We measure, squeeze out the excess links completely. By the way, the old chain is replaced with a new one in the same way.
  • Install the chain in the squeeze with the reverse side. We press until the pin clicks. You can skip this click. Be careful, otherwise the pin will go further than necessary.
  • It is much more convenient to use a connecting pin, the long rod of which is fixed in the links, and the excess is removed with pliers.
  • Now we move the wheel, so the chain will stretch a little.

Setting up your bike derailleurs is easy. You do not need to have special skills and knowledge for this. Follow the instructions and you will succeed!

Why does the chain slip on a bicycle?

Any bike ride, be it a speed race or a simple ride, has a significant impact on the drivetrain. During the ride, the chain and the stars experience significant friction against each other, as a result of which they become unusable over time.

Timely lubrication and debris removal is essential to reduce friction and increase transmission life. However, even with proper care, the cyclist can face a problem of wear when the chain slips, the gears shift poorly, or the engagement of the links on the teeth of the sprockets is lost.

Reasons for chain slip through stars

Transmission misbehavior problems occur under load: pedal pressure while shifting gears. Slippage is especially pronounced when driving uphill when this load is at its maximum. This pattern is equally true for a single speed bike and a speed bike. Let’s figure out what serves as a prerequisite, and whether it can be fixed.

The reasons why chain links break off the stars are simple and transparent:

  • elongation of links due to wear;
  • the teeth of the rear and front sprockets are worn out;
  • both factors at the same time.

The latter option is most common if the chain or cassette has not previously been changed separately.

Chain length is an indicator of chain wear. The standard size is 304.8 mm. Stretching leads to the fact that the teeth of first small, and then large stars are grinded down more, due to which the efficiency of gear shifting on a high-speed bicycle decreases several times. Especially noticeable lengthening will affect the transition from lower to higher speeds.

If the distance between the rollers of the chain increases, the width of the sprocket teeth decreases. You can easily notice the development with your own eyes. To calculate the degree of cut, the thicknesses of the teeth of a worn and a new star of the same size are compared.

And finally, another reason why a transmission wears out quickly is incorrect gear shifting. For simplicity, remember once and for all:

  • In front, the stars are counted from the smallest.
  • Rear cassette numbering starts from largest sprocket.
  • It is necessary to combine higher gears with higher (large stars in front and small ones in the back), and vice versa.
  • Since there are fewer sprockets on the front cassette, there are several sprockets for each sprocket on the rear cassette. For a standard 3X8 system:
Rear1, 2, 34, 5, 66, 7, 8

Proper use of the gearshift system avoids excessive chain skewing, which would cause tremendous wear on parts.

How to fix the problem

In this section, consider a situation where the chain starts to turn or fly off, the switches with the tensioner are set correctly. As already found out, the problem is caused by wear and tear. A radical option is to change the cassettes along with the chain. But there are also more gentle options that will allow the system to serve more.

So, remove the chain from the bike, straighten and measure its length. By its size, you can judge its wear:

  • up to 306.4. slight elongation, the problem is only in the stars;
  • up to 308 mm. average wear.
  • over 308 mm. completely unusable.

After measurements, you need to inspect the front and rear cassettes. When the chain is stretched to 307.9 mm, wear is likely to show up on small to medium rear sprockets. They can be replaced separately without buying a new cassette.

Replacement is recommended at average wear, however, at first, the inaccuracy of the transfer and slip can only worsen. This is due to the mismatch between the roller spacings and the tooth width. Over time, the transmission components will rub together.

Is there an alternative? Yes, it exists, and it is a circuit breaker. In general, these devices are used for safety purposes in cycling when the chain is likely to fly off the stars. But with their help, you can maximize the riding time with worn out parts.

The pacifiers consist of a disc (rockring) and rollers. There are also rollerless models, where the chain “calms down” only by the frame. Dual roller versions are used for high speed bikes where each corresponds to two chainrings.

Adjusting the derailleurs on a new bike

Slips and inaccurate gear changes under normal wear and tear indicate deranged derailleurs. This problem usually occurs with a new bike, or if the chain and sprockets have recently been replaced.

General scheme of switch adjustment:

  • set the optimal cable tension;
  • adjust the course in lower gears;
  • setting the chain stroke on the highest stars.

For the rear sprocket, you still need to set the correct position of the tensioner, which will compensate for the chain slack. Bicycle Rear Derailleur Setting:

  • Loosen the screw and remove the drive cable.
  • Set low gears with chain in 1: 1 position.
  • By turning screw L, the alignment of the guide roller with the star is achieved.
  • Install the cable into the derailleur.
  • Turning the pedals, set the highest gears: the chain on the small sprocket in the back and the largest in the front.
  • Use screw H to match the roller and the active sprocket in the same plane.
  • The correct tensioner position is 5mm from the lowest sprocket in a 1: 1 chain position.

Similarly, the front derailleur is adjusted according to the scheme: setting the restrictions on L. adjusting the top gears on H. setting the tension of the drive cable. However, first you need to check the coincidence of the switch roller with the plane of the outer stars. Perhaps just setting the rear derailleur will be enough. And of course, checking the operation of the transmission, in particular, the chain tension, in practice.

In principle, adjusting the switches will last for a long time. The correct use of the speed system will help to reduce the wear rate, and the timely elimination of negative factors will allow the transmission to last as long as possible.