Lubricate the dogs.
Squeeze some grease onto the drive ring and make sure there is some grease between the pawl and its location. This is where the most stress and resistance is, please note that any force applied to the pedal is transmitted to the wheel through these four or six points of contact, so they deserve the most attention. Put some grease on the spring to hold it in place. Put some liquid oil on the drive ring. Make sure that the flexible seals are installed correctly, use your fingernail to adjust the edges of the seal so that the rubber edge fits into the groove intended for it. Make sure the seals are in their grooves and when installing the freewheel mechanism, avoid moving the seals and pinching them.
We remove the cassette.
Remove the rear wheel and secure the cassette with the “whip”. Wrap the “whip” around the third star clockwise or larger (so that the longest piece of whip is wrapped around the star). Insert the circlip remover and wrench so that its key handle is to the left of the whip handle, but close enough to be grasped with both hands at the same time. Now squeeze and unscrew the retaining ring and cassette firmly. The distance between the circlip and the locknut on the axle may not be sufficient to accommodate some brands of tools, but Shimano or Park pullers always work.
How to disassemble a sprocket on a speed bike
Tighten the cassette retaining ring.
Make sure that the retaining ring is screwed on correctly, it can be easily screwed in skewed, especially if it is made of aluminum alloy. If something is wrong, unscrew it and screw it on again. The tightening torque is best set to 40Nm (approximately 30ft-lbf). Use a 12 ”long wrench with slightly less force than the axle nut. For a single-speed chain, tighten the wheel nuts to hold the wheel (do not tighten at all) and check the chain tension in the most “protruding places” (this is because there are certain tolerances on the geometry of round parts, which may be slightly non-round, as a result of the chain tension will change slightly as the wheel rotates). Slowly pedal back and find the position where the chain has the least slack, and in this position, finally tighten the wheel nuts. Tightening the chain in the position where the cranks are at the lowest tension will increase all the noise from the system.
Change the sprocket on the rear cassette
The set of transmission stars of the rear wheel is several times larger than the front one. The standard kit includes eight components, and in high-speed models (or on a sports bike) there are 9 or 11.
It is worth mentioning right away that a cassette or ratchet can be placed behind. The cassette is a modern version with an internal splined mounting on the hub axle. Ratchets, as an outdated option, can only be found on a budget high-speed bike. The set usually includes 5-7 gears. External fastening, threaded, removable tool differs from cassette.
The fundamental difference from the cassette is its integrity. it is impossible to change the star separately on the ratchet. Here, either all at once, or nothing at all. Therefore, we will consider how to install a new sprocket on the cassette.
As with replacing the leading stars, special tools are required here:
- cassette remover;
- chain whip-retainer;
- adjustable wrench or head;
- optional: wrenches, chain release.
When removing the cassette, you will need to first remove the rear wheel from the bike and then the axle nuts. At the same time, when replacing the sprockets, you can also clean the chain. to remove it, you need a squeeze.
Sequence of work:
1. Remove the rear wheel with a 15 wrench, with an eccentric mount everything is simple. unclench the lever and loosen the fixing nut.
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The next step is to unscrew the axle nuts. You will need a 17 key for it. To roll the mount off the rotating axle, we put on an additional nut to fix the axle.
Unscrew the bearing cone and pull out the bearing from the opposite side.
Remove axle with taper and bearing. About the bushing components: if necessary, you can immediately replace them with new ones.
Place the whip on the largest (lowest) star. We will rotate it clockwise.
Use an adjustable wrench or a head to turn the puller counterclockwise.
It is so easy to shoot a cassette at home. Most modern star sets are collapsible, you can install one or two new stars. However, in case of severe wear, when half of the cassette is worn off, it makes no sense to change them separately. Difficulties can also arise if the largest sprocket has been erased, on which all the others are usually attached.
Is it possible to dismantle a cassette without a puller and a whip? In principle, this can be done with a slotted tube and a spanner. The whip can be made by yourself by welding a piece of an old chain to the metal handle of the knife.
Rear transmission assembly:
Check transmission operation and adjust rear derailleur. Timely replacement of sprockets will save you from unpleasant surprises on trips and will, in general, increase the resource of the bicycle transmission.
We wash the insides twice.
Put on your safety goggles, take a can of GT85 or WD-40 and spray a continuous layer on the inside of the freewheel hub. Then pour plenty of machine oil over the parts, let it drain, wipe dry and repeat the operation. Then install the gasket, lubricate the joint and put the freewheel back in place.
How to disassemble and lubricate the cassette hub
Water and dirt can easily get inside the cassette hub and if this happens, your bike will clang and screech like an old elevator.
To disassemble and clean the bushing, you need special tools and a little additional knowledge on how to do it correctly. In this guide, we will walk you through and show the entire process step by step. But if you doubt the correctness of your actions, especially in the third step, it is better to entrust it to a specialist.
8 Little tricks.
After installing the springs and pawls, wrap the compression tool around the pawls (the hook should point outward). Gently slide the freewheel back onto the axle, partially inserting the pawls into the drive ring, but leaving enough room to pull out the compression tool, disengage and gently pull out. The freewheel hub should fit into place, turn it counterclockwise while reattaching. this will help the dogs get into place. If you do not have a tool for squeezing the pawls, a piece of sturdy thread is suitable for sewing. Wrap it around the dog sleeve a couple of times to tighten it, then a couple more times. When the freewheel is partially in place, gently pull the thread out. Install the locknut.
Bicycle cassette designation
Usually cassettes are marked with a range and number of stars, for example 11-36T 10-speed. Road bike cassettes can be compatible with one of the following systems: Shimano or Campagnolo. third-party models are labeled accordingly.
Removing the bicycle rear wheel cassette
When the rear sprockets are worn on the bike, as well as when replacing the spokes on the right side or adjusting the cone and lubricating the insides of the hub. you must remove the cassette.
To remove the cassette, we need several tools. a puller, a key for it and a whip (you can use an old piece of chain).
- The first step is to remove the rear wheel.
- The stars are pulled to the ratchet (ratchet) by a special nut. In order to unscrew such a nut, we take a cassette remover and a wrench corresponding to the size (usually 17-21)
Since the nut has to be unscrewed counterclockwise (in the direction of the free wheeling of the sprockets), then we will need to use a special tool. a whip.
We throw the whip on the largest star, keeping the cassette from rotating with it, unscrew the slotted nut with a puller wrench. In some cases, in order to unscrew the nut, you will need to make a lot of effort, since it can be strongly pulled.
When the nut has given way, a crackling sound will usually be heard, this is normal, since the smallest sprocket and spline nut have a grooved surface so that they will not unwind randomly.
According to the material of the stars
- Steel (chrome-plated, nickel-plated or otherwise coated) is inexpensive, durable and the most common material. Cheap cassettes naturally serve less expensive ones.
- Titanium alloy. used in top cassettes (sometimes only on large stars), very high price, low weight. There is no consensus regarding the durability of titanium stars versus good steel stars.
- Aluminum alloy (anodized). used in Weitwinner cassettes. Very low weight, high price, low resource (may be at the level of a bad steel cassette).
Classification of cassettes
Now that the cassette has been removed, you can inspect the mechanism.
Installing the cassette must be done in the reverse order.
- If there is a protective plastic ring, the first thing to do is put it in place.
- If the cassette is not combined into one non-collapsible mechanism, then you should put on the sprockets one by one, starting with the largest, while do not forget about the intermediate washers (gaskets) between the stars.
- When all the sprockets are correctly installed, it is necessary to tighten the spline nut, this is done with a cassette puller and a wrench. Since we will have to spin in the direction of the wheel’s movement, we do not need a whip.
- Tighten the nut with a wrench, force about 40 Nm.
A bicycle cassette is a gearshift assembly, a bicycle cassette assembly is a fastener for transmission stars and spacers. Stars attach to fasteners in descending order.
The smallest diameter sprocket is in the final row from the hub. The gear speed is also counted. To raise the gear means to shift the chain to a big star.
Maintenance of the cassette of a high-speed bike must be carried out systematically: replace damaged sprockets, chain or the entire clutch unit. A cassette is also called a ratchet with a similar set of stars, but significant differences.
Differences between ratchet and cassette:
A ratchet is a set of sprockets combined with a sleeve by threaded or spline fastenings. The bushing is outside, the stars are non-separable, completely installed.
A significant minus of the ratchet is that if one section of the sprocket is damaged, you have to replace the entire mechanism.
The cassette is made in the form of a set of stars connected to a freewheel drum on the rear hub. The parts of the assembly are collapsible, reinforced with an end nut that holds the teeth, and prevents the fastening from being screwed on while the bike is moving.
The difference between a ratchet and a cassette
Before removing the sprockets from the rear wheel of a bicycle, you need to decide on their design. It is important to distinguish between ratchet and cassette. Although they are similar in appearance, they are very different inside.
In the ratchet, the freewheel is installed together with the sprockets. It is such a monolithic system that is simply screwed onto the bushing. The cassette can be disassembled, so one worn sprocket can be replaced. Unlike a ratchet, it is not a monolith with a freewheel mechanism, but is put on it.
To remove them, you need different pullers. It is important not to confuse them with each other, because they are not interchangeable. They have different splines. If you are still afraid not to distinguish a ratchet from a cassette, a photo will be an excellent tip in this matter.
It is important to set it up especially accurately, since if the adjustment is not good enough when switching 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 the chain is not too skewed.
Next, 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 coincides.
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.
Make sure the cock is level first. If it is still bent, you can contact the service to straighten it, or try it yourself. Alternatively, you can 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 setting on the bike in this case will not work for you.!
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 cable 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 that holds the rear crossover cable.
By rotating the bolt with the inscription “H” you need to make sure that the switch rollers lie in the same plane with the desired sprocket.
Then lightly stretch the cable and tighten the bolt holding it. Over-tensioning the cable will make the crossover difficult to work.
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 sprocket.
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.
How to repair a Shimano rear derailleur
If, while driving, something starts to click, and the gears are not changing clearly, then usually we begin to adjust the rear derailleur. Sometimes it doesn’t help and it means that it’s time to fix it.
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In fact, it may turn out that it will not be possible to repair it. This happens if the switch is pulled into the spokes and the frame is skewed. Sometimes, the frame itself begins to play, and it is already impossible to accurately position the rollers above the stars of the rear cassette.
If everything is ok, and the frame is straight, and there is no backlash, then here it is already worth looking at the guide rollers themselves. They can either grind off or start to play on the axles.
Idler rollers wear out
You can also kill videos. I’ve encountered this on both my Scapin MTB and the Trek Eqinox E7. over, they were killed in a very original way.
On a Shimano XT derailleur (MTB bike), the roller is cracked due to improper shifting. There could be two options: either the gearshift was immediately thrown by more than three stars, or the gears were changed under the pressure of powerful legs. As a result, the video jammed. and it cracked. I tried to glue it with super glue. but it helped for exactly 2 trips. Then I just changed it to a new one.
Dusty grease in derailleur rollers
The second version of the worn out rollers is more sophisticated and perverted. I already wrote that the previous owner of Trek Eqinox E7 simply smeared a thick layer of grease on the chain. And this grease not only clung to the dust, it also crammed into all the cracks. That is, this abrasive grease gets into all bearings. After disassembling the roller, I saw that it was jammed into a brass plain bearing.
Killed and new outer rollers of the rear derailleur Shimano 105
As a result, the bearing was crushed and bored (the teeth on the roller were completely intact) and the roller began to play on the axle. He played to such an extent that in the extreme left position he reached one asterisk, and in the right. to the second. At the same time, the switch itself was in place.
Killed and new Shimano 105 idler rollers
I had to get new rollers from Shimano XT (fortunately, I had a kit “just in case”. and put instead of the dead ones. The outer (Narrow) new roller was on the industrial bearing, the old one was just sliding. The new guide roller (G-Pulley) was on the ceramic bearing, that is, almost eternal, if not lubricated
We use ABRO THREADLOCK thread lock for assembly
The frame on the Shimano 105 derailleur is made of aluminum, so do not over-tighten the mounting bolts. The favorite thread lock was taken, applied to the bolts. After that, the bolts were tightly screwed into the holes. Watch the effort very closely, I repeat. Simply if you rip off the thread in the aluminum frame, it will be very difficult to restore it. You can, of course, screw in an ordinary bolt and nut there, but this is somehow non-kosher
As a result of all the work, we get the assembled rear derailleur, completely ready for work How to set up and adjust it. in the next post.
Have you ever fingered the rear derailleurs yourself??
Dish of the day: Swing under the waterfall Interesting. the water turns on depending on the position of the swing, or you have to “fall” into the gaps?
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What to do if your bike‘s derailleur is broken
Transmission components must be kept in good condition at all times, lubricating the chain promptly, adjusting switches and troubleshooting.
As the kilometers increase on the bike, individual parts wear out, and if maintenance is not performed on time, the part may become unusable altogether. In this article, we will look at the most common problem associated with speed derailleurs.
It must be understood that the speed changes only when the chain moves forward. If you jerked the shifter, then you need to turn the pedal so that the chain spreads from one star to another. If, when switching, clicking or any other extraneous sounds are emitted, you need to adjust the switching.
The main reasons for inaccurate switching:
- The transfer cable is torn, stretched, or is on the verge of breaking.
- The switch itself is broken or the spring in it is worn out.
- The teeth of the rollers are worn down.
- The switch needs to be adjusted.
- The chain or cassette is worn out.
- There is a lot of dirt in the chain.
Bicycle speed switch how to disassemble
How to fix a bicycle rear derailleur
- – Hexagon wrench set;
- – Open-end wrench or key-bone;
- – Pliers;
- – New cable for the derailleur (in case the old one has fallen into disrepair);
- – Graphite grease;
- – Nippers;
- – Phillips screwdriver;
- – Rag for cleaning parts and hands.
Wipe down the rear derailleur and remove any dirt. If grass or branches are crammed into the switch, be sure to remove them before starting repairs.
Turn the bike over and place it on the handlebar and saddle so that you can pedal freely.
Remove the hex screw or cap screw that holds the cable down. It is very easy to recognize it, since the cable fits exactly there, and this is one point for the entire switch.
Take the released cable in your hand, examine it carefully. If the cable is intact, it is not damaged. it does not unravel, all the fibers are in order, and there is only a small mark on the cable, then go to step 5. If the cable is damaged, it must be replaced with a new one.
Hold the cable with your hands, switch the lever on the handlebars and see if the cable moves with each click. If there are no dips or wedging in the cable, proceed to the next step. If the cable gets stuck somewhere, you need to remove the jacket from it and grease it with graphite grease.
Put the shirt back in place. Set the cable aside. Go to the switch. There is an L and H screw on the switch (they are signed on most models).
We rotate the bicycle pedals. Since the cable is not locked, the chain must move to the end position. If this does not happen, turn the screw L with a screwdriver (in both directions, we look at the situation) until the chain lies confidently on the extreme star. No deviations allowed!
Only after step 7 is performed correctly, do we move on to tightening the cable. The cable rests against a special thrust bearing on the body (so-called fine adjustment). Before inserting the cable back into its position, the thrust bearing must be tightened almost completely, leaving 2-3 turns free.
We insert the cable into its position. Using pliers, pull the free end, tighten the cable and fix it with a nut or hex bolt. Everything is almost ready. It remains to adjust the screw H.
We shift the gear to the last, largest rear sprocket. Ideally, the chain should switch freely and stay on this star. If clicks occur, or the chain does not lie on the star, it is necessary to turn the screw H left and right with a screwdriver to find its optimal position. If you set the position incorrectly, the last gear will not engage, or vice versa. the chain will fall between the cassette and the hub flange.
There is also another bolt on the switch, which most likely will not be required. It determines the longitudinal position of the switch. It is easy to find as it is located close to the switch axis and rests against the cock. This bolt only needs to be turned if the chain slips under load during movement.
The task is completed, your switch is configured. It’s actually very simple. so don’t be afraid to repair the switch yourself.
Note that if the derailleur is incorrectly set, the chain will fall between the sprockets on the cassette. Because of this, there will be a clicking sound, chain overshoots will appear and the chain itself may break. The determining factor in the repair and adjustment is the setting of extreme positions.
You also need to remember that switching problems are not always associated with the switch. it is likely that the chain is already too worn out and slips by itself or the teeth of the cassette have grinded.
Using different bike speeds helps maintain a certain rhythm of leg movement while riding, which avoids increased stress on the body. The speed switches, which are located on the steering wheel, need to be adjusted periodically. This problem is especially true if the bike is equipped with position switches.
Install the derailleur so that it is parallel to the star system. The distance between the largest sprocket and the derailleur bar should be between 1 and 3 millimeters, inclusive. Shift the left shifter to first gear and place the chain on the smallest sprocket. Make sure the cable that moves the front derailleur is taut. Raise your bike. While pedaling slowly, shift the shifter to second speed. Make sure the chain goes over to the middle sprocket when doing this. If the chain is still in the same position, tighten the screw on the shifter to tighten the cable on the front derailleur. Try shifting the shifter back to first speed. If the chain does not move to the small sprocket, re-adjust the cable. Ultimately, you need to tighten the cable so that the derailleur moves freely both up and down. Crank the pedals slowly and check that all bike speeds are operating when shifting the shifter forward and backward. Adjust the rear derailleur. With the chain on the rear wheel on the small sprocket, shift the shifter to the maximum position. In this case, the line of the derailleur rollers should be parallel to the smallest star when viewed from the back. Turn the stop bolt marked “H” one turn. if necessary, gently bend the derailleur so that the rollers are parallel to the small sprocket. Shift the shifter sequentially from a higher gear to a lower one to check for proper chain shifting. If the chain jumps over one gear or remains stationary, adjust the cable tension. Repeat these steps checking each star.