Gears shift poorly: where to start

When to stop

Here the main scenario is the rear derailleur. The front derailleur, hub gear, and gearbox require their system's manual.

1. Describe the direction and section of the failure

1. Note, the chain does not run well to the large rear sprockets, to the small ones, or in both directions.
2. Write down whether all gears or just a specific section of the cassette are affected.
3. Think about falling on the right side, transportation, removing the wheel and the recent replacement of parts.

If you know how to safely secure your bike in a repair stand, check the shifting without load by slowly rotating the pedals with your hand. Stay away from the chain and spokes, turn off the electric drive. If there is no stand, limit yourself to examining and describing the behavior you've already noticed.

2. If the shifter is controlled by a cable

Inspect the available sections of the cable and sheath — jackets: no fraying, sharp bends, or ends coming out of the stop. Park Tool identifies friction in the cable and jackets as one of the causes of slow shifting. Lubricating the chain does not eliminate this cause.

After a fall, check for obvious damage to the derailleur mount. The metal frame mount is often called a 'peacock'. SRAM recommends measuring its alignment with a tool: good performance of part of the cassette does not exclude misalignment. Do not correct the fastening by hand. Systems like Full Mount, such as Eagle Transmission, do not have a separate derailleur hanger — they need their own order of checking.

If the initial checks are passed and only a small adjustment of the working cable mechanism is needed, use rear derailleur setup guide. Electronic and damaged systems require their own procedure.

Do not tighten all the screws in a row. The H and L screws limit the extreme positions; The Park Tool describes them separately from gear indexing. For self-adjustment, you need the instructions for your specific derailleur.

3. If the system is electronic

Start with the manufacturer's feeding instructions. For a wireless system, check both the battery of the shifter and the battery of the grip-shift: these are different elements. SRAM explains the verification of AXS indicators. Battery locations and signal values differ among systems.

Write down whether the shifter responds to each command. When commands go through but the chain does not engage the sprockets properly, a simple recharge may not solve the issue: a mechanical check of the setup and condition of the parts is needed. When there is no response, the condition of the power supply and connection needs to be checked before adjusting the gearing. Do not use a random combination of buttons for resetting.

4. What to order and what to report

Needed shift diagnostics. Choose «Transmission» in the catalog of workshops and your city. For example, you can look at Birota; clarify electronic system support directly.

After the work, ask to check the entire gear range and protection against the chain coming off the cassette. Save the list of replaced parts; it will be useful if the symptom returns.

Sources and boundaries of verification

The material was prepared by the FATRACING editorial office for technical manuals. The inspection by the invited mechanic has not yet been carried out. The instruction of your model determines the order of maintenance, tightening torques and compatibility.

• Park Tool: Advanced Troubleshooting — cable, jackets and nature of the failure.
• Park Tool: Rear Derailleur Adjustment — limiters.
• SRAM: Rear Gear Adjustment — mount and compatibility.
• SRAM: AXS Digital Troubleshooting — power and communication.

The sources were verified on October 9, 2026. The workshop did not check the text.