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The short version

  • If a step feels uncertain, stop and use a qualified bicycle mechanic.
  • Never ride with brakes, steering or wheels that you suspect are unsafe.
  • Use the component manufacturer's instructions for torque settings and model-specific procedures.
01

Before you start

Identify the derailleur and shifter model, number of chainrings and maker's setup sequence. Inspect cage alignment, chainrings, crank security, cable and housing before changing limits, and record the starting screw positions so a mistaken adjustment can be reversed.

  • Use tools that fit the fastener properly
  • Keep small parts in removal order
  • Do not force a seized or cross-threaded component
  • Check the maker's manual for your exact part
02

Work out whether the fault is alignment, limits or cable tension

A cage that rubs across much of the gear range may be at the wrong height or angle, while a chain that falls off at one end points to a limit or alignment problem. Cable tension affects the shift between rings but cannot straighten a bent cage or chainring.

Identify whether the system is a double or triple and follow the derailleur maker's sequence. Avoid judging the setup only in extreme cross-chain combinations that the drivetrain maker advises against using.

Inspect the chainrings, crank and cable before adjustment. Bent teeth, side-to-side chainring movement or a frayed cable require repair rather than progressively tighter limits.

03

Step by step

  1. 1

    Inspect chainrings, cable and derailleur cage for wear or damage.

  2. 2

    Confirm the cage height and angle match the component instructions.

  3. 3

    Set the low limit so the chain cannot fall towards the frame.

  4. 4

    Set cable tension and test shifts under light pedal pressure.

  5. 5

    Set the high limit so the chain cannot overshift beyond the outer ring.

04

Checks before riding

Shift under light pedal pressure through the chainring and rear-sprocket combinations the drivetrain is intended to use. Confirm the chain moves reliably without falling towards the frame or crank and that ordinary usable combinations do not produce persistent cage contact.

  • The chain remains on both outer limits
  • Usable gear combinations clear the cage
  • The cable and derailleur fixing remain secure
  • Shifts work under light pedal pressure
05

When to use a bike shop

Stop if the cage or chainring is bent, the crank has play, the cable is damaged or neither limit position can prevent an overshift. A mechanic should also assess repeated chain drop or a setup whose compatibility between shifter, crank and derailleur is uncertain.

Primary sources

Check the current guidance

Rules, schemes and product ranges can change. These live links are the authoritative or independent starting points used for this guide.