How to disassemble a rear sprocket on a bicycle

How to remove / put on a cassette?

Insert the cassette remover into the slotted nut.

We put a whip on the largest sprocket of the cassette.

Holding the cassette with the whip, rotate the puller with a wrench. The effort is likely to be quite decent. Unscrew the nut completely, and then remove the cassette.

On the removed cassette, you can now determine the degree of wear of the cassette.

When to shoot?

In most cases, removal is necessary when the bike needs to be serviced regularly (for example, in the spring or fall). It is urgent to remove the cassette when there is a sharp slip of the pedals during the ride.

Installing a cassette looks exactly the opposite of removing:

  • Put a cassette on the drum
  • Tighten nut
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How to remove / put on the ratchet?

It will not be possible to remove the ratchet mechanism just like that, so we need a special tool. a puller, an adjustable wrench or a 24 or 27 millimeter wrench, depending on which model of the part is installed on your bike. To remove the cassette you will also need a cassette whip.

Insert the puller into the ratchet and pull the puller nut counterclockwise. It will take a lot of effort to loosen the slot, and exactly the same when tightening.

Cassettes and ratchets for beginners

Bicycle cassette. rear chainring system for changing the gear ratio combined into a cassette.

The cassette is fixed to the rear wheel hub. The cassette is a consumable material, it wears out over time, which requires its periodic maintenance. replacement of the chain, individual stars or the unit as a whole.

The cassette is stars (all or individual, depending on the design) attached to a fastener that has grooves, and there are projections of the corresponding configuration (slots) on the hub body, which ensures the correct installation of the cassette. The ratchet is hidden inside the drum.

The cassette drum mechanism has several advantages:

  • stars from 8 to 12 on modern models
  • Less rolling resistance than a ratchet
  • Less weight
  • Easier to take off
  • Greater mileage

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Ratchet. ratchet mechanism with threaded or slotted mounting on the hub, the ratchet is located outside.

  • The number of stars ranges from 5 to 7
  • Large load on the thin axle of the bushing due to which they bend
  • It spins with great torque, it looks like this: as the pedals rotate, the ratchet spins on the thread of the sleeve every time, more and more. Sometimes, then unscrewing the ratchet is almost impossible!

The cassette is a more complex, high-quality and functional unit than a ratchet. Should you opt for a cassette tape? Definitely yes!

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Types of cassettes

All cassettes fit onto slots and are interchangeable. Let’s say an 8-cc cassette can be changed to an 11-cc cassette, having the necessary switch and shifter, without changing the rear hub. If we look at the cassettes in profile, we will see the cassettes are almost the same in width, although the number of stars is different. In order to keep the same cassette width, the distance between the stars is reduced.

  • On the pins there is a block of stars fastened by pins, and the stars are separated by spacers. Such cassettes are installed on bushings with steel drums or simply on inexpensive bicycles. The advantage will be that they can be disassembled to zero by removing the pins from the grooves, but, at the same time, they cannot be placed on light aluminum drums, since the high torsional load (especially of large stars) will damage the drum.
  • On the spider. the stars are dressed on the so-called single spider that goes in the form of a ladder.

The torsional force is transmitted not only to one star, but to the entire block of stars dressed on a spider. Thus, the load on the drum is reduced. Also, such cassettes are lighter. On a spider, you can change the last 2-3 stars. On 2 or 3 spiders. the stars are dressed on 2 separate spiders.

This is done so that the depleted stars can be replaced individually with blocks of stars, and not change the whole cassette entirely. In case of wear, you can replace one of the blocks on the spider or the lower 2-3 stars separately. Depending on the cassette level.

Solid milled cassettes. the entire unit is made as one piece.

It is put on on the slots on the left side of the drum, and fixed on the lower star. The cassette is at the same time a slot for the drum. Among the analogues, this is the most expensive option. Sophisticated manufacturing process pays great price and requires a dedicated SRAM-XD drum per hub.

Cleaning and lubricating the cassette

Bicycle transmission mechanisms sometimes wear out not so much from applied loads, but from careless maintenance. dirt stuck together with lubricant spoils the operation of the system and grinds off the teeth faster. Before servicing the cassette, it is necessary to remove it. the analysis and its correct sequence are above. The sprockets on a bicycle are cleaned with a special flat brush:

Long and hard villi are able to crawl to the very axis and clean out dirt from the most problematic places. After we have cleaned the cassette, we lubricate the chain and further forward to meet new adventures!

Diagnostics and care:

  • Tighten the wheel hub bearings. In principle, you can not remove the mechanism itself, but the bearings are easier to remove when removing the entire device, they are quite small, it is very difficult to remove them.
  • Lubricate the system. Sometimes the reason for the improper operation of the bike is not only the lack of lubrication, but also its abundance.
  • Replace broken dogs. The reason for repairing the transmission can be a broken pawl that does not catch the wheel mechanism, or a spring that pushes it.
  • Sprocket teeth wear. The most common reason. The entire device needs to be replaced. Small diameter sprockets break most often.
  • Cleaning of dirt and grass that clogs between the stars when riding.
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What is a ratchet?

Ratchet is a ratchet mechanism consisting of a freewheel, sprockets and a threaded ring. The design transfers rotation from the pedals to the wheel through the chain, while simultaneously allowing movement without the need to pedal. It is screwed onto the threads of the axle of the rear hub of the bicycle. If the sprockets wear out, they unscrew and change completely to new ones.

disassemble, rear, sprocket, bicycle

Cassette and ratchet should not be confused. In modern bicycles, they began to use a cassette. a device that is more advanced than a ratchet. The design consists of stars assembled together, which are put on the sleeve and secured with a nut, and the holes in the middle are equipped with grooves with which it clings to the drum. Inside the drum there are pawls, springs and a ratchet. It is easier to remove the cassette and replace the unusable sprockets with new ones. It can be easily dismantled in any conditions, and the removal of the ratchet is best done on a workbench. This requires not only a special tool, but also significant physical effort. The impossibility of repair is its main drawback. Plus a small number of stars and fragility.

It just works. The system has a pawl that engages the rear of the transmission mechanism, at which time a slight crackling sound is heard. From this cod comes its name. If there is no sound, it means that it will pull the chain forward when the pedals do not rotate.

Removing and disassembling a bicycle wheel ratchet

Most multi-speed bicycles have a simple rear hub, which contributes to the lightness and smoothness of the ride. How the bike rides depends not only on the geometry and shape of the frame, but also on the state of the transmission system. over, it is the rear bushing that is most loaded, since it has a complex device. It holds a ratchet or cassette.

Puller and key

Removing a long-established ratchet requires considerable effort. It can get stuck and rusty. There must be special tools available, which are a puller and a large adjustable wrench or wrench.

The puller is a slotted wrench for disassembling or installing the ratchet mechanism. It is unscrewed counterclockwise using a wrench or adjustable wrench. Ratchet and cassette tools are similar but completely incompatible, do not confuse them.

    The rear wheel is removed first. If the ratchet has not been removed for a long time and it is difficult to remove it with a puller, then it is better to use WD-40 grease. It is better to lubricate the threads from the inside, under the stars, and leave for several hours.
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When removing, there may be a problem in the lack of effort to unscrew the stuck mechanism. This problem is solved by lengthening the tool. This can be done with a small tube. Take two bolts 6–8 cm in size and select the nuts for them. One is inserted into the hole in the puller, and the other into the hole in the handle of the adjustable wrench. Clamp with nuts. Insert a tube between the bolts. It turns out a lever with which it is much easier to rip off a stuck device.

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How to disassemble the ratchet?

To repair the ratchet with your own hands, you need a hammer and center punch. Instead of a center punch, you will need a large nail or self-tapping screw. It is better to disassemble the device on a wheel so that you can hold it.

  • The ratchet spins on the wheel. A center punch is inserted into the hole on the nut, and by turning clockwise with a hammer, the mechanism is disassembled.
  • The stars are removed with a puller and a key. There are balls inside under the nut. There is also a second ball track on the wheel.
  • To prevent the balls from scattering, you must put a rag or box.
  • The smallest asterisk is unscrewed counterclockwise. The rest are just filming.

Now you need to look at the condition of the mechanism, pawls and lubrication. Dogs wear out most often. They can be replaced. A special repair kit made of dogs and rings is produced. Be sure to wash the ball bearings. If the balls are black and there are frayed metal particles, then the bearings have broken. Each one needs to be examined. If there are dents on them, then it is recommended to replace them.

Next, we collect all the parts in reverse order. The flare nut must be tightened with force, and the play for the sprockets relative to the wheel should be adjusted with inlaid, thin rings.

Thus, it is much cheaper to repair the mechanism with your own hands and does not take much time and effort. And it is necessary to perform such actions regularly so that cycling is pleasant and safe.

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