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Many who service their bike themselves are faced with the need to replace the rear sprocket unit (cassette). And as soon as we start to understand this, we understand that it is not so simple, because there is a lot of contradictory information floating around on the Internet. Today everything will become clear :)
It is important to know for sure that you have a cassette installed, otherwise you may buy the wrong tools to remove it, so I recommend reading the article.
Tools needed to remove the cassette
In order to remove the cassette without any problems, you will need two tools:
- Whip()
- Special puller for removing the cassette
I use bike hand keys The process of removing the cassette from the sleeve
The goal of the whole process is to remove the cassette lock nut, and the cassette itself can then be removed by hand without any effort.
This is what an 8-speed cassette looks like on an eccentric hub. You can also see a lock nut with the inscription “Huper Gude-c” Since the hub uses a freewheel mechanism, we will need to fix the cassette so that it does not spin - this is what the whip is for.
Holding the cassette with a whip, we unscrew the locking nut counterclockwise and remove the cassette from the hub drum. Ready! When you have a tool, it’s all very simple!
Installing a cassette on a bicycle hub
In order to install the cassette on the wheel hub, we will need to carefully look at the cassette itself, at the splines of the hub drum, and have a cassette puller (a whip is not needed for installation).
Why do you need to look at the tape? This is necessary because the distances between the splines are different and the seat has only one correct option. Therefore, you can take a long time to select and spin the cassette so that it fits on the drum.
In general, we need to find the largest distance between the splines (hollow) on the hub drum, and the largest spline (bulge) on the cassette - this bulge is usually marked with a triangle. Then combine them with each other, then the cassette will fit like its own.
Next come individual sprockets (1-2 pieces); they are put on in the same way as the cassette unit. Please note that you may encounter a cassette consisting entirely of individual stars, which will have to be put on one by one.
Well, completing the installation is tightening the lock nut. It is tightened with a puller clockwise with a force of 40 Nm, which is usually indicated on the nut.
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Any cycling enthusiast should be able to repair and clean a bike. One of the main parts of a bicycle that requires systematic cleaning is the cassette on the rear wheel. The cassette is a functional speed transfer unit.
A significant disadvantage of the ratchet is that if one section of the sprocket is damaged, the entire mechanism has to be replaced.
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 mount from screwing together while the bike is moving.
Popular materials for cassettes
Cassettes are made from different materials and differ in a certain level of strength and wear resistance:
Aluminum alloy cassettes are lightweight and low in density. Popular among experienced cyclists to reduce the weight of the bike.
Titanium is a high-quality material with medium weight and density. Titanium cassettes are characterized by a high level of strength and are not subject to corrosion. The only disadvantage of titanium cassettes is the high price.
Steel is the most popular material for the production of bicycle parts. A significant drawback is the heavy weight.
The advantage is that the metal is durable and resistant to mechanical stress. Steel parts are exposed, so it is recommended to buy a chrome-plated, nickel-plated or blued version.
Number of stars
Cassettes are selected according to the number of stars. Older bicycle cassettes were mostly seven chainrings; now road and mountain bikes are equipped with 8/10/11 and even 12 chainring cassettes.
The number of stars can be determined by the marking, for example, 11-36 T, 10 speed indicates the number of teeth (1 small, 36 large) and 10 stars.
Instructions for removing the cassette
First, the wheel and disc axle are removed from the bicycle, after which access to the cassette is opened.
The cassette is removed using a 12-claw puller, a wrench or gas wrench and a whip.
The puller is a medium-sized wrench with a slotted hole for the drum.
Stages of work:
- Use a whip to secure the cassette and begin to unscrew the locking ring with a gas wrench or a puller.
- Place the key inside the cassette until the splines fit tightly into the grooves of the sleeve.
- Place the chain of the whip in links on the teeth of the large star so that the handle is on the right.
- Holding the star with a whip, unscrew the open ring with a puller or a gas wrench.
- After unscrewing the ring, remove and lay out the stars and spacers one by one.
- Parts are inspected for damage, wear or contamination. Damaged parts must be replaced.
Required Tools
Cleaning and Lubrication
During operation, the elements of the parts deteriorate due to the impact of stuck together dirt; in this form, the teeth of the cassette wear down much faster.
It is better to clean an unassembled cassette using a special flat brush with long and stiff bristles that can penetrate difficult areas and remove dirt from the mechanism.
If the stars are completely disassembled, you can use a simple brush and detergent.
After all the dirt has been cleaned, wipe each part dry. Simultaneously with the cassette it is necessary.
A serious approach with complete dismantling of the cassette is advisable for those who like to travel through forests and swamps.
Cyclists riding on asphalt roads can get by with bicycle lubricant around the perimeter of the cassette and chain.
Apply lubricant only to a chain that is completely dry after washing.
After applying lubricant to the chain, you need to drive it through all the sprockets of the cassette; to do this, switch the gears and rotate the connecting rods by hand so that the chain jumps from sprocket to sprocket.
The chain will go from the small star to the big one and in reverse order. There is no need to lubricate the cassette; the chain itself will lubricate the contact areas of the cassette teeth and the rear derailleur rollers.
Putting the cassette in place
Installing a cassette is exactly the opposite of dismantling it. During installation, ensure that the sprockets are tightly seated on the bushing splines.
The sprockets should be installed with the utmost care to avoid damaging the spline flanges.
Using a set of wrenches, tighten all the stars and screws onto the bushing, then screw the clamping nut counterclockwise along the threads.
It is important to observe the exact order of landing of the stars for tight adhesion to the spacer rings. If the parts are installed incorrectly, the stars will be at a great distance from each other, this will distort the operation of the speed switch.
The end nut must be tightened to the maximum level using a wrench or gas wrench. To tighten the nut with reverse threading, the wheel is installed in a horizontal position to increase the pressure on the gas wrench.
Detailed video instructions on servicing the cassette and bushings:
With a ratcheting mechanism and secured with a locking ring. Special slots on the hub body allow you to install the cassette in the correct position.
Tools needed to remove the cassette
- The “whip” key is a key with a bicycle chain attached;
1. Remove the bicycle wheel, then install the puller so that its splines fit completely into the grooves of the locking ring.
2. Install the whip on the sprocket so that the links of its chain sit tightly on its teeth. The handle of the whip should be located to the right of the cassette, and the chain on top.
3. Place the adjustable wrench on the cassette remover and turn it counterclockwise, while holding the handle of the whip, preventing the sprockets from spinning.
If the chain jumps off, it is possible that the cassette sprockets are very worn, or the whip is faulty. In this case, try throwing it on a large star.
4. Unscrew the retaining ring completely, then remove and arrange the sprockets and intermediate washers. Lay everything out in order so that you don’t mix anything up when assembling.
Cassette removed, now it can be cleaned or replaced.
When installing a cassette, the main thing is not to confuse the order in which the parts are installed. In order to correctly install the sprockets, they have grooves of different widths, and the bushing has the same slots, thanks to them the teeth will fit in the right order.
1. Some cyclists advise lubricating the surface of the hub before installing the cassette, but I think this will be unnecessary. First, the chance of corrosion is too low. Secondly, the friction between the bushing and the sprocket is also not so great as to cause damage. Thirdly, dust and sand may stick to the lubricant, which can lead to accelerated wear of parts.
Apply lubricant only to the threads of the locking ring, then it will be easier to unscrew it next time.
2. Put on the sprockets one by one, but don’t forget about the spacer rings. In some cassettes, all or several sprockets can be connected into one non-separable unit - a “spider”. But most often all the stars go separately.
3. In some cassettes, to install the last sprocket, you need to press it. Check again that everything is installed correctly, press the last sprocket with one hand, and screw on the locking ring with the other hand.
4. Screw the ring all the way in, but do not tighten it yet. Check again that all the stars are parallel to each other and level. If something bothers you, disassemble the cassette and fix the problem.
5. If you are sure that everything is assembled correctly, then take the cassette puller and tighten the locking ring clockwise until it ends.
That's it, the cassette is assembled. Once again, inspect the correct assembly and you can install the wheel in place.
When my cassette got worn down for the first time and the teeth began to resemble thorns, I took care to change the sprockets behind the rear wheel. I took off the wheel, looked at the cassette, and didn’t understand what and “where to put it” and “how to turn it.” But other people's experiences helped me.
In general, in order to remove the cassette you need 2 tools (or three). If you take the “company” from Shimano, then each of these two keys will cost you 25 dollars. The first is actually a piece of chain mounted on a metal handle. We pay money exclusively for the brand and “made in Japan” :)
The second is also a branded key with a handle, which is inserted into the cassette nut. It is convenient because you do not need additional tools to turn the key. The issue price is also about 25 dollars.
Instead, you can buy a key like this - a puller (prices are very different, depending on the manufacturer). You just always need to remember that if you buy a cheap key “for 1 ruble” from a Chinese on Ali or eBay, it may be enough for exactly 1 repair. Or even not enough for repairs at all :)
How to remove the sprocket cassette without a puller?
Sometimes, instead of the first chain tool, people advise to “throw a rag over the sprockets” and turn the nut with a puller. I'll be honest - I tried it. The rag turned into rags from the sharp bicycle teeth.
The second option for replacing the branded cassette retainer is to take an old chain. Almost any self-respecting cyclist has one or two old chains, especially if you rotate chains and replace them in a timely manner. If the chain is not changed in time, then you can easily end up with up to 250 dollars:). So, we take the chain, put one end of it on the cassette, and wrap the other end around the tire wheel, fix it there and turn the nut with a puller [bad advice;)]. As a result, the chain thrown over the tire pushed the tire down to the rim and dented the latter.
The third option came naturally when I studied the device of the clamp in detail :) We again need an old chain, a stick, 4 screws and a screwdriver. It is better not to use nails - they are torn out of the stick with a bang.
We put everything together, as in the photo of a professional Shimano cassette remover.
Removing a bicycle cassette
We take the second important tool, and an adjustable wrench. We throw the puller over the wheel and install the toothy thing into the nut. Well, my favorite adjustable wrench is there :)
Then press down on both sides.
It turns out to be something like this - or rather, nothing works out :) I took a stick made of some pressed cardboard, which happily showed me its guts. The next stick was made from dried birch.
We put it back on the wheel.
Press down on both sides. We hear micro-clicks of the nut (there is a ribbed surface, and when you tighten the nut, it is securely fixed).
We remove the cassette from the hub, wash and inspect each sprocket. If you don't take care of cleaning and lubricating your bicycle chain, then a stretched chain can pretty much ruin your sprockets.
If the wear on any of the sprockets is quite high, then it is better to change that sprocket. Most often, stars of the “favorite program” are developed. Usually medium, since there is the lightest pedaling effort. In my case, the sprockets are in pretty good condition, and after troubleshooting, I decided to put them back together in the same form, without replacements.
And, as long as you have removed the sprockets from the wheel (and they are not in the way), you can also sort out the wheel bearings, especially if they are crunchy. The procedure is quite simple if you know which way to approach the process.
Replacing rear wheel sprockets on a bicycle
Assembly proceeds in reverse order. By and large, mixing up the sides of the sprocket (which side to put outward) tends to zero, since there are guides on the hub. And it’s problematic to put asterisks “back to front.” But, be careful - I think you can hammer a star in there with a hammer :)
In general, if your sprockets are often “eaten” due to a stretched chain (and this often happens with low-quality chains), consider buying a normal bicycle chain, for example, a Campagnolo Record, the chain is designed for 8,500 kilometers.
Then, lastly, install the nut. We twist it by hand until it stops. Here you can no longer use a chain on a stick, since the rotation will be in the other direction and the hub will not rotate. But I still recommend that you use your homemade tool.
The tightening torque of this nut should be quite strong - 40 newtons per meter (4 kilograms applied to a 1 meter long lever). And if you simply tighten this nut with a wrench (without holding it with a chain), then there is every chance of turning the spokes out of the wheel.
After reassembling the rear wheel, I also adjust the rear derailleur of the bicycle, fortunately, this only takes 10-15 minutes with proper skill. When driving, the rear derailleur settings still “go away” and gear shifting becomes unclear, so these 10 minutes can save you a lot of nerves.
Alex "On the Bike" Sidorov
Dish of the day: Ken Block released a new video - Gymkhana - 9. My heart skips a beat when I look at his tricks.
Water and dirt can easily get inside the cassette hub and if this happens, your bike will clank and grind like an old elevator.
To disassemble and clean the bushing, you need special tools and a little extra knowledge on how to do it right. In this guide we will explain 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.
A nine-step guide to fixing your cassette hub.
List of tools you will need:
- 10mm and 12mm socket wrenches
- Folding socket wrench set
- Extension attachment for wrench (pipe or block)
- A short piece of chain with a handle for unscrewing the rear sprockets (“whip”)
- Retaining Ring Puller
- Open end wrenches for flare nuts
- 17mm key
1. Remove the cassette.
Remove the rear wheel and secure the cassette with a 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 snap ring remover and wrench so that the wrench handle is to the left of the whip handle, but close enough to be grasped with both hands at the same time. Now squeeze firmly and unscrew the locking ring and cassette. The distance between the locking ring and the locknut on the axle may not be sufficient to accommodate some brands of tools, but Shimano or Park pullers always work.
2. Remove the axle and bearings.
Check the condition of the freewheel bushing (cassette with a freewheel mechanism), pay attention to how worn it is, maybe it’s time to replace it or just clean and lubricate it. To do this, grab it with your hand and shake it. If it wobbles more than a couple of millimeters from side to side, then it's time to replace it. If not, then it will be enough to simply clean it and lubricate it well. Install a 14 or 15mm flare nut wrench on the left side of the wheel (where there are no sprockets) and loosen the locknut (usually) with a 17mm wrench on the left side. Unscrew the locknut, then the flare nut and pull the axle assembly with the opposite flare nut out of the bushing, while collecting the falling bearing balls on a clean rag.
3. Remove the freewheel freewheel ratchet mechanism.
To get to the insides of the freewheel bushing and replace the old grease or simply replace it with a new bushing, you need to remove it. Insert a 10mm socket wrench into the hollow bolt holding the freewheel on the right side and turn counterclockwise, using a fair amount of force to remove the bolt. You may need to use a small extension on the handle of the wrench to make it easier to move the bolt out of place. Hubs that are similar to those produced by Shimano, for example from Joy Tech, may be removed slightly differently. The retaining bolt in them usually needs to be unscrewed from the left side, inside the hub mechanism, using a thicker socket wrench.
4. Wash the insides twice.
Wear safety glasses, take a can of GT85 or WD-40 and spray a solid layer on the freewheel insides. Then pour plenty of machine oil onto the parts, let it drain, wipe dry and repeat the operation. Then install the sealing gasket, lubricate the joint and install the freewheel mechanism in place. Tighten the retaining bolt well. Before installing the axle and bearings, wipe off any old oil, clean them, and then re-oil them with fresh oil. Some loose bearing hubs use different balls on different sides: 7/32" balls and a slightly modified cone shape on the freewheel side and a standard cone with 1/4" balls on the left, they should not be mixed. Lightly coat the grooves on the bushing with grease and install the cassette. (Please note that if you are using a Shimano 10 speed cassette on a 9 speed hub, a thin spacer ring is required.)
5. Campag hubs.
The new Campagnolo Centaur, Chorus and Record hubs are disassembled differently. Secure the axle on the left side with a 5mm socket wrench. Then, using a 17mm open-end wrench, turn the locknut on the right side clockwise and unscrew it. In order to remove the freewheel mechanism, you need to pull it, while the axle will remain inside. The ratchet pawls and their springs will remain in place. Removing the Mirage and Veloce hubs, as well as the old style Chorus and Record hubs, may require that you first loosen the small socket head cap screw (about 2mm) located in the right locknut. On newer versions it is no longer there, so remove the lock nut on the right using a 17mm wrench, holding the axle with a 5mm socket wrench or a second 17mm wrench.
6. Campag hubs old and new styles.
On new Mirage/Veloce hubs, the left lock nut may come off first. If this happens, pull the axle and freewheel to the right side with a sharp jerk. Do all this carefully over a rag so that small parts such as springs and pawls fall onto it. There are currently two types of springs in use: multi-coil and single-coil. The former is used in old Hope hubs and old and new Campagnolo hubs, the latter in new Hope, Campag, Shimano and a variety of other lightweight hubs. When disassembling, pay attention to the order of operations, as well as special attention to the orientation and location, in particular the side on which the drive ring is installed and the location of the pawls.
7. Lubricate the dogs.
Squeeze some grease onto the drive ring and make sure there is some grease between the pawl and where it sits. This is the area that experiences the most stress and resistance, keep in mind that any force applied to the pedal is transmitted to the wheel through these four or six contact points, so they deserve the most attention. Place some grease on the spring location to keep it in place. Drop some liquid oil onto the drive ring. Make sure the flexible seals are installed correctly by using your fingernail to adjust the edges of the seal so that the rubber edge fits into the groove provided for it. Make sure the seals are in their grooves and when installing the freewheel, be careful not to dislodge the seals or pinch them.
8 Small tricks.
After installing the springs and pawls, wrap the compression tool around the pawls (with the hook facing outward). Carefully slide the freewheel back onto the axle, pushing the pawls partially into the drive ring but leaving enough room for the compression tool to be pulled out, disengage it and carefully pull it out. the freewheel should fit into place, turn it counterclockwise while installing it in place - this will help the pawls fall into place. If you don't have a tool to compress the pawls, a piece of strong sewing thread will work. Wrap it a couple of times around the bushing with the pawls to tighten them, then a couple more times. When the freewheel is partially inserted into place, carefully pull out the thread. Install the locknut.
9. Tighten the cassette retaining ring.
Make sure that the retaining ring is screwed on correctly; it can easily be screwed on crookedly, especially if it is made of aluminum alloy. If something is wrong, unscrew it and screw it on again. It is better to set the tightening torque to 40Nm (approximately 30ft-lbf). Use a wrench with a 12-inch long handle, applying slightly less force than you would on the axle nut. For a single speed chain, tighten the wheel nuts to hold the wheel (do not overtighten) and check the chain tension at the highest points (there are certain tolerances on the geometry of round parts, which may be slightly out of round, resulting in As the wheel rotates, the chain tension will change slightly). Rotate the pedals slowly back and find the position where the chain slacks the least and in this position finally tighten the wheel nuts. Tightening the chain in a position where the cranks provide the least tension will increase all noise from the system.
