How To Adjust The Rear Derailleur On A Bike

Adjustment position

Operating principles

Rear derailleur operation still seems like a seven-sealed mystery to many cyclists. After all, he can reliably and unpretentious perform his functions, but one day “live your own life”. If you have no experience in eliminating such “independence”, then this can become a significant problem, especially if such a malfunction falls like snow on its head on the way. Therefore, usually novice LOVERS take their “iron friend” to the workshop, where an experienced technician fixes this problem in a few minutes. However, what operations he performed, what he regulated, lubricated or twisted, remains unknown. Therefore, you need to be patient and understand the principles by which the Shimano rear derailleur functions. If you follow the guidelines below, you will have no difficulty in further servicing your bike with your own hands. It is only important to study the necessary theoretical base and independently confirm it in the practice of work.

Required tools

First of all, you may need:

  • Hex keys or a set of keys (3 and 5 mm required)
  • Phillips screwdriver.

Before starting debugging, it is important to make sure that the mechanism is still functional. At Shimano, the rear derailleur adjustment is carried out according to the manufacturer’s recommended instructions, you may have retained it if you purchased the chain tensioner separately. If the bike was purchased as an assembly, then usually THESE documents are available.

How To Adjust The Rear Derailleur On A Bike


Similarly, with the gear shift cable. if it is rusty and constantly wedges in the casing, then there can be no talk of any reliability or ease of use. However, this situation is easier to fix, if you just add graphite grease to it in the required amount, and, perhaps, the adjustment of the Shimano rear derailleur will advance faster.

Tensioner and its adjustment

This adjusting screw is used very rarely as it helps to adjust the position of the upper pulley to the cassette along which the chain travels. If it is not twisted, then the above details can touch each other and cause a lot of inconvenience. However, this situation is very rare, since this unit is fastened securely enough and there is a backlash in it, which would contribute to its weakening.

At Shimano, rear derailleur adjustment is very accessible, however it may seem a bit overwhelming to beginners. Although this mechanism is simple in design, adjusting it requires meticulous attitude and patience. Haste is inappropriate here, especially if the work is being performed for the first time.

READ  How to disassemble the sprocket on the rear wheel of a bicycle

Shimano. Rear derailleur setting. Shimano rear derailleur adjustment

The topic of today’s article is about customizing your bike. After all, it has a lot of different nodes, which requires close attention and regular maintenance. Especially closely we will dwell on the products of the Shimano company. Setting the rear derailleur has some nuances. If you have installed equipment from a second manufacturer, you should not neglect the materials described in this article, since the principles of operation and debugging are common for all such products, because they have a similar design.

Jacket and steel cable

The adjustment of this tool is very important, since the cable is responsible for how far the speed switch moves when the shifters click. If the tension is excessive, then the convenience of gear selection becomes much more difficult, and sometimes the chain can jump to adjacent sprockets or very slowly downshifts. At the same time, if the effort is not enough, then nothing will happen when the position is changed. Therefore, a properly tensioned cable can eliminate half of the complications that arise with Shimano Alivio systems. Their rear derailleur is often inconvenient due to the structural features. After all, the line of the middle class, to which this type of device belongs, is NOT intended for too intensive use, like a professional one, for example, Deore or its analogues.

Important setup steps

Special cases and their resolution

If the chain slips when pedaling with a little effort, then it is most likely stretched along its length and needs to be replaced. When used in this form, it is possible to harm Not only the stars of the system, but also the cassette, which will render them unusable. A worn chain crushes or grooves their teeth, making these shift elements unusable.

When changing speeds, it is necessary to make sure that the chain moves without distortions. Although its place is fixed if you have a Shimano Deore or higher class rear derailleur installed, these cases are not uncommon for people using more common attachments. This malfunction leads to accelerated wear of the system elements and the chain, therefore it must be taken very seriously.

If the gear shift is suddenly disrupted and no longer works, then most likely there is a problem with the cable. Either it broke off, or it was not securely fixed with a fixing bolt.

If you have a Shimano attachment that has already been set to the rear derailleur and is NOT functioning properly, then you need to make sure the cable runs freely in your shirt. If it has cracks or loose winding spots, it must be replaced. Similar problems can also arise if the bike cock has been bent.

READ  How disc brakes work on a bicycle

The device and reasons for the failure of the rear chain spreader

Rear derailleur fine adjustment

From time to time, you will have to fine-tune the rear spreader in the following cases:

  • If the repair, replacement, adjustment of the chain drive units was performed.
  • New cables and shirts installed on the bike.
  • Low-quality cables stretch strongly during operation, and plugs at the ends are squeezed out of the shirts.

Adjust the switch by unscrewing the hollow cable tension screw half a turn to the left. It is easier to unscrew the screw when the cable tension is released. when the shifter is reset to the highest speed. Be sure to check the accuracy of the setting while riding a bike.

That’s all in the rear derailleur setting. If you consider all of the guidelines given here, the rear ejector on your bike will work like a Swiss watch. But in no case should you be tormented with an overly stubby switch. Better to replace it with a new one.

Release the cable

To do this, it is enough to screw in the tension screws on the rear spreader and on the handlebar near the shifter all the way, and then pull the cable out of the clamping screw.

Experts DO NOT recommend completely removing the Loose bicycle cable, but inspect it for damage (if found, the cable will have to be completely replaced) and thoroughly lubricate it, first cleaned it of dirt, it is imperative.

Adjustment elements

The cable is fixed on the spreader. At the command of the shifter, it either loosens or tightens, we move the frame by the very same. Despite the simplicity of the device, as many as five objects are provided in the design of the dereiler, which sets the course of its operation:

  • Cage bolt with nut securing the cable.
  • Chain adjuster screw.
  • Drum that sets the cable tension (in more expensive systems, it is located on the shifter).
  • 2 end position limit screws (L. low gears, H. high gears).

When is it necessary to adjust the rear derailleur

The process under consideration does not cost constantly, with systematic maintenance of a two-wheeled vehicle. as experienced mechanics say, “do not interfere with the bike ride. ” Therefore, you need to clearly understand what may be the reason for adjusting the rear derailleur:

  • The cable and its shirt are either faulty or require lubrication.
  • Rear Diverter Frame Attachment (called “Cock”) Curved.
  • Cassettes and / or sprocket chains on the rear wheel are worn.
  • The tensioner rollers are clearly stuck on the rear spreader.
  • The shifter for changing the speeds on the steering wheel has become unusable.

Bicycle front derailleur

The transition to the setting of this mechanism is possible only when the rear derailleur is set. This feature is important to take into account before starting work. Figure 2 shows the switch (round, black).

READ  How to choose mountain bike pedals

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, reactivate adjuster L. To adjust stop H, the chain moves to the largest sprocket at the front and smallest at the rear. The adjuster will help to 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.

Additional accessories

Normally, setting up a Shimano rear derailleur for normal operation is limited to a quick readjustment. To complete it, you need to hang out the rear wheel, which will require one of the following:

  • Repair rack.
  • Rear wheel stand.
  • Ironing board.
  • Friend’s help.

Adjusting the chain tensioner

This process is simple and even an inexperienced cyclist, far from the principle of repairing his vehicle, will cope with it in a few minutes. What should be done:

  • The chain is translated to the smallest sprocket in the front and the largest in the back.
  • Pay attention to the rotation of the tensioner rollers. if at the time of the chain throwing it hits the star in the cassette, then you need to tighten the chain tension screw. By this action, a gap between the clutching elements of 5 mm is established.
  • The chain is rearranged to the largest sprocket in the front and the smallest at the back, along the way, the chain tension level is checked in this position.

What is the adjustment

Before embarking on the process of adjusting the rear derailleur of the bicycle, you need to know what is provided for such work. There are 5 adjusting screws on the bike:

  • Hollow screw with a drum for tensioning (this is one of the ways to adjust) the cable.
  • Restrictor gait propeller, marked with “H”. only works for the smallest sprocket.
  • Restriction screw gait spreader with markings “L”. only works for the biggest sprocket.
  • Cage bolt with nut. designed for fastening the cable.
  • Special screw for tensioning the chain.

Note: some models of bicycles (usually this refers to inexpensive brands) are not equipped with a cable tension drum or chain tension screw. But in this case, manufacturers install an adjusting drum on the steering wheel in the shifters. This makes it possible to adjust / adjust the level of cable tension directly in the movement of the bicycle, only first you will need to throw the chain onto the smallest sprocket.