I'm looking for a cheap, used set of cranks for a bike that was fished out of the garbage :)

Because the cranks won't be on a bicycle when I go buy them, how can I tell if they're bent or not?

I'm thinking of taking a BB spindle and pedals along, putting the cranks on and trying to rotate them somehow...

Any ideas?

2 Answers 2


I've actually never seen bent cranks, so that's probably the least of your worries. And if they are bent, then I don't think you'd be able to tell until they're mounted on the bike.

Bringing pedals is a good idea - not to check for straightness, but to check if the pedal threads are damaged. If they're square-taper cranks, you should also check the dust cap threads - if they're messed up, you may not be able to take the cranks off again.

  • 1
    +1: Additionally Square taper can be stuffed easily without any real sign of serious damage by riding with them loose. Look for any sign of damage to the taper surfaces. I doubt you would be able to tell - mounting them onto a BB might be worth the effort.
    – mattnz
    Commented Mar 2, 2015 at 1:26

An alternative for used cranks for an old bike for "beater" style usage is to get a cheap, unbranded (new) chainset online. You will at least then have the assurance of any warranty that the company provide, and much lower chance of getting sold something broken.

In the UK there are websites like SJS Cycles which provide parts in all price ranges. Last year I needed a new chainset for my commuter on a student budget, and got something like this for (visibly) a good price. Its not the smoothest of chainsets, but it does the job, especially when you're on a budget. I'm sure there are similar companies selling in the US.

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