What AreDrive-Chain Adjusters?
The adjusters used to set final-drive chain slack, commonly located around the rear axle. Procedures and correct slack figures are model-specific.
Simplified animation — not to scale.
In plain English
Drive-chain adjusters are the mechanism used to set the final-drive chain's slack. On most motorcycles they sit around the rear axle in the swingarm, and they move the rear wheel forward or backwards to tension the chain. Some motorcycles use a different, model-specific adjustment system instead. Both excessive slack and excessive tightness can be harmful — too loose can let the chain jump or come off, too tight can damage the chain, sprockets and gearbox output shaft. Correct slack, the position the bike must be in when measuring, and the exact adjustment steps are set out in the motorcycle's handbook.
How it works
Typical adjusters use threaded blocks either side of the rear axle. Loosening the axle nut and turning the adjuster bolts moves the wheel back or forward along the swingarm, changing the chain's slack. Alignment marks or measuring points on each side help keep the wheel straight. After adjusting, the axle nut is torqued to the handbook figure, and any locknuts on the adjusters are secured. Because chain wear, sprocket wear and correct slack all vary by model, there is no universal number to aim for. Always use the specification, measuring conditions and torque values printed in the motorcycle's handbook.
Signs of trouble
- ⚠Chain feels loose or slaps against the swingarm
- ⚠Chain feels overly tight and noisy when the suspension compresses
- ⚠Uneven wear on the chain or sprockets
- ⚠Wheel appears misaligned after adjustment
What affects the repair?
We don't publish a generic price for this part because a responsible estimate needs a named motorcycle and a recent quote. These are the factors a qualified technician will weigh up.
- •Diagnosis: intermittent or system-wide faults may need dealer-level tools before the actual part can be identified.
- •Accessibility: some parts are quick to reach; others require significant fairing, tank or engine-cover removal.
- •Model differences: prices and labour times vary widely between manufacturers and specification levels.
- •New vs used: a genuine OEM part fitted at a franchised dealer costs more than a serviceable used or aftermarket part.
- •Calibration / coding: some parts require post-fit calibration, coding or a road test, which adds labour time.
Sources and further reading
Last reviewed: July 2026