E-Bike Pedal or Crank Arm Loose

In plain English

Pedals unscrew themselves if they're loose, and the left pedal has a reverse thread so pedaling doesn't loosen it. Crank arms are held by a bolt on the axle. If a crank arm wobbles, riding on it soon ruins it, especially with motor power.

Watch how it's done

Video by Park Tool. It may show a regular bike: on an e-bike, switch off and remove the battery first, and unplug the motor cable before taking off a hub-motor wheel.

Work from the top. Steps go from free and easy to shop jobs. Switch the bike off before touching any connector. Tick each step as you go. Your progress is saved on this device.

1. 1Find which part is looseFree Grab each pedal and wiggle it, then each crank arm. A pedal loose on its own axle may just need tightening. A crank arm moving on the bike's axle is more serious.
2. 2Tighten the pedals the right wayEasy Right pedal: tighten clockwise. Left pedal: tighten counter-clockwise (it's reverse threaded). Use a pedal wrench or the hex key slot inside the pedal axle.
3. 3Tighten the crank boltEasy Remove the dust cap if there is one, and tighten the crank bolt to the torque printed on the crank or in your manual.
4. 4See a shop for a wobbling crankShop job If the crank still wobbles after tightening, the crank or its axle may be damaged. On mid-drive e-bikes, crank work is best left to a shop.

Parts you might need

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Only buy a part if the free steps didn't fix it. Always match the voltage and connector type to your bike.

• Pedal wrench

  A thin, long wrench that fits pedal flats and gives extra leverage.

  Link coming soon

• Small torque wrench

  Tightens bolts to the exact number printed on the part, so nothing is too loose or over-tight.

  Link coming soon

• Bike grease

  For pedal threads, seatposts and other contact points that creak.

  Link coming soon