I recently bought an old (and cheap) road bike and I quickly noticed that the bike's crank set is "broken" because it had a weird bump when pedalling.

I took apart the crankset, and noticed that the wedge connecting one pedal to the crank as well as the crank itself is pretty worn down. I switched out the wedge and filed down the worn down part of the crank so it is flat again. I also added a shim of metal in between to make up the filed down part.

This fixed the problem for some time but now it is back, so I think it is time to replace the crankset or find a more long term fix for the problem.

I want to replace the crank set for something with a more durable attachment mechanism.

I have never tried doing this myself but I looked around a little to find out what I even have to keep in mind when look for a new crank. The measurements of the current crank are the following:

  • Housing width is 70mm
  • Housing diameter is 40mm
  • Bearing cage 34mm

I started look for parts but I really don't know how to find them and what I should look for and this is what I was hoping y'all could help me. So basically I need a shopping list. :D

  • 1
    You have a cottered crank sheldonbrown.com/cotters.html It is possible to repair the crank you have so that it is dependable. At a minimum it will involve a new cotter pin.
    – David D
    Sep 1, 2022 at 15:51
  • Can you share any details about repairing the crank? (I have a crank where a loose pin ate a fair bit of the axle flat material.)
    – jayded-bee
    Sep 1, 2022 at 20:40

1 Answer 1


When you replace a cotter pin, you need to 1) make sure it is the same angle of bevel, and 2) the same diameter as the hole in the crank arm. For this reason it is best to replace both cotter pins at the same time. If you needed to file the spindle, you should consider replacement. If you are not attached to the three piece steel crankset, consider replacing it with an alloy cotterless crank. You will need to verify what threads your bottom bracket is, but the most common is British.

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