How to adjust the rear derailleur on a bike

Mountain Bike Shimano Rear Derailleur Adjustment

Any modern sports bike is equipped with a multi-speed transmission. The presence of a large number of sprockets, both front and rear, required the development and implementation of spreaders. However, the flexibility of the system did not allow the creation of dealers that would not be subject to regulation. However, you should not be afraid of it. All Shimano devices are identical in design and there is nothing complicated in setting them up. Knowing the instructions, any cyclist will follow it, even in the field.

Steering wheel switches

If the shifter breaks on the handlebars, the cyclist will feel it right away. the cable tension instantly weakens, so it’s easy to “diagnose” the problem. In this case, the shifter must be replaced, but experienced cyclists do not recommend purchasing expensive components. with proper operation of such parts, even not the highest quality will manifest itself only on the positive side.

Why did the switch start to work poorly?

There can be many versions on this matter. One of the most common is the banal stretching of the cable and the sagging of the shirt. Occurs on new bicycles of any category after 200-300 km of run. Other options may be considered, or even variations of them:

  • The cable is fluffed up or there are bumps on its surfaces in places of bends.
  • Shirts are dirty. They are enough for a maximum of two cable changes. As a preventive measure, flushing the inner surfaces of WD-40 can be considered (splash and move the cable along the guide).
  • Bent cock (part that holds the “cross-link” on the frame). Sometimes the traditional Shimano bike rear derailleur setting does not work. In this case, it is worth inspecting the holder for bending. The rooster is leveled with a special machine or on a frame. Care must be taken when performing an operation on an aluminum frame structure. the material is fragile.
  • Backlash in the spreader. It is revealed very simply. it is enough to stand on the side of the bike, grab the place where the cable enters and move it away from you. On Shimano Tourney, Altus equipment groups, backlash is allowed. The rest should be absent. The presence of large displacements introduces fuzziness in the switching mechanics.
  • It is not recommended to lubricate the cable, especially with viscous consistencies such as grease. the effect of light switching will disappear quickly, and the lubricant will attract dirt.
  • It is undesirable to deliberately lengthen or shorten the shirts. there will be increased friction in the bending points.

Rear derailleur adjustment technology exemplified by Shimano Tourney

For full-fledged debugging of the mechanism, experts recommend removing the chain. This is a common case. Having understood the essence of the problem of loss of working capacity, this manipulation may not be required.

Adjusting the cable tension

Such an adjustment is carried out literally in 2 steps:

  • We tighten the cable and fix it with a mounting bolt. over, you need to do this with your hand, it is inappropriate to use pliers in this case.
  • We rotate the hollow screw with a drum and tighten the cable in such a way that with one click and pressing of the shifter, the transfer device easily and unimpeded (without delay even for a second) switches from one sprocket to another and back.
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It is worth noting that the process of adjusting the cable tension takes several minutes. it is enough to adjust the correct transition only between two adjacent sprockets, and everything else will work automatically.

Note: some models of bicycles have a groove for the cable in the clip. make sure when adjusting that it lies exactly in it, and is not pinched in the wrong position.

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 touches the star in the cassette, then you need to tighten the chain tension screw. By this action, a gap between the clinging 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.

How to fine tune the rear derailleur

From time to time, bike owners have to fine tune the rear derailleur. As a rule, such work is carried out in the following cases:

  • repair, adjustment or complete replacement of chain drive elements was carried out;
  • new cables and their shirts were installed on the two-wheeled vehicle;
  • poor quality cables were installed on the bike and they constantly stretch during operation.
adjust, rear, derailleur, bike

In this case, the switch is adjusted by unscrewing the hollow cable tension screw. it is enough to make a half-turn to the left. After setting up, be sure to check the operation of the mechanism. ride a bike in different speed modes.

Rear Derailleur Adjustment

Using the tips and tricks given in the presented material, you can carry out the whole process yourself. The only thing to remember is that the rear derailleur, which is badly worn out, must be replaced: no adjustments / adjustments / replacement of the cables will help.

Bicycle front derailleur

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 to position the chain in the optimal position without friction and excessive tension on the chain. At the end of the work, be sure to check the quality of its implementation.

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Additional accessories

Usually, 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.

Adjustment elements

The cable is fixed on the spreader. At the command of the shifter, it either loosens or tightens, thereby moving the frame. Despite the simplicity of the device, the dereiler design provides as many as five objects that set the course of its work:

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

How to Adjust a Rear Derailleur – Limit Screws & Indexing

How to adjust the rear derailleur of a Shimano speed bike: detailed instructions

There is a popular belief among newbies that it is better not to go into the gearshift mechanism. The argument is. I don’t know how, I’ll knock everything down. However, there is nothing to be afraid of. self-adjusting the brakes on a mountain bike is no more difficult than adjusting the transmission. In addition, the shift index system is configured in such a way that it cannot be broken. The process should start with preparatory activities.

Briefly about the main thing

The idea of ​​setting the rear derailleur from the Shimano range is to achieve an immediate bust of the chain of the cassette stars by the chain at the command of the shifter. There may be several reasons for the incorrect operation of the mechanism, and not all of them are eliminated by adjustment. There can be only two versions of the poor functioning of the rear transmission, which can be eliminated by adjustment:

  • The spreader has been in operation for a long time or has been replaced: adjust the border positions of the frame.
  • The dereiler has an impressive resource reserve, but it went wrong. clean / replace the cable and shirts, adjust the cable tension by rotating the drum.

Final adjustment

The listed transitions must be performed when installing a new “switch”. Basic adjustment can acquire a separate relevance in the case of a deep revision of the drive, shirts and cables, but not always. The main criterion for the emergence of the need to adjust the limiting points is the violation of the clarity of the transition of the chain to the extreme positions.

Initial setup

The essence of the basic setup is to set the boundary positions of the switch. In this case, it is advisable to remove the chain. this will be more convenient. Standing behind the bike, we perform the following operations:

  • Using the adjustment screw for the limitation of the highest gear (H), achieve the location of the cassette rollers and the smallest cassette sprocket in one plane. There is one secret. if the device is not new and has backlash, the rollers are not aligned with the extreme star of the cassette, but literally by a hair’s breadth from the hub.
  • Overcoming the spring force, move the derailer by hand to the extreme left position (closer to the bushing) and, turning the screw L, ensure the alignment of the plane of the rollers with the line of the largest sprocket. Again, if there was a difficult transfer to the rear sprocket with the most teeth, the switch should be shifted a few microns closer to the spokes.
  • Put on the chain.
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Why did the switch start to work poorly?

There can be many versions on this matter. One of the most common is the banal stretching of the cable and the sagging of the shirt. Occurs on new bicycles of any category after 200-300 km of run. Other options may be considered, or even variations of them:

  • The cable is fluffed up or there are bumps on its surfaces in places of bends.
  • Shirts are dirty. They are enough for a maximum of two cable changes. As a preventive measure, flushing the inner surfaces of WD-40 can be considered (splash and move the cable along the guide).
  • Bent cock (part that holds the “cross-link” on the frame). Sometimes the traditional Shimano bike rear derailleur setting does not work. In this case, it is worth inspecting the holder for bending. The rooster is leveled with a special machine or on a frame. Care must be taken when performing an operation on an aluminum frame structure. the material is fragile.
  • Backlash in the spreader. It is revealed very simply. it is enough to stand on the side of the bike, grab the place where the cable enters and move it away from you. On Shimano Tourney, Altus equipment groups, backlash is allowed. The rest should be absent. The presence of large displacements introduces fuzziness in the switching mechanics.
  • It is not recommended to lubricate the cable, especially with viscous consistencies such as grease. the effect of light switching will disappear quickly, and the lubricant will attract dirt.
  • It is undesirable to deliberately lengthen or shorten the shirts. there will be increased friction in the bending points.