How to Repair a Bicycle Crank

Bicycle cranks attach to a device called the bottom bracket in the center of the bicycle frame. Cranks attach to the chainrings and pedals, allowing the pedal motion to be transferred into forward motion. Over time the cranks loosen, causing unwanted noise, vibrations and missed shifts. Repair your cranks with 30 minutes or time in your own workshop. Most crank noises and vibrations are due to the crank loosening on the bottom bracket spindle.

• 1

  Put the bicycle into the bike work stand and clamp down the securing device at the bicycle seat stem.

• 2

  Turn the pedals and shift the left-hand side shifter to watch the chain move over the chainrings at the cranks. Feel for any vibrations or side to side motion on the cranks. If present, proceed with work.

• 3

  Place the crank wrench into the center Allen screw. Reach to the other side of the bicycle and place another crank wrench into the screw on the opposite side crank.

• 4

  Use opposing force with the crank wrenches, turning to the right on one side and the left on the other to tighten the cranks. Tighten as firm as possible.

• 5

  Spin the cranks and pedals and test the cranks. Spray the cranks at the frame/bottom bracket spindle with the dry lubricant.