my pedals ruined my cranks!

I had had the same wellgo pedals on for about 2 and 1/2 months, and upon trying to remove them, discovered that under the serious strain they had endured while doing trials and muni, that they had destroyed the thread in my cranks! I can no longer use these cranks, and found that within hours the other cranks that I put these pedals in were also destroyed! That means, that one set of pedals has destroyed 4 of my cranks!

This really makes me mad.  How can I prevent this with my next set of cranks?  Should I take them out of the cranks every once in a while?  The cranks may have been crap, and both pairs came from stealth torkers.


What exactly happened? I am not sure what you mean when you say your pedals destroyed your cranks. How exactly did they do it. I am interested since I happen to own 2 Stealth Torkers, and would like to avoid this problem.


The pedals ripped the thread out of the cranks.

Sounds fishy. It seems to me that a secure pedal (nice and tight in the crank) would sit, VERY securely until undone, if put in correctly in the first place.

A) Was your left crank on the left side? If not, it may have undone itself, and you ruined it that way.

  1. Did you have to use unusual force to screw the pedal in? If so, you stripped it there.

These are some ideas of what could have been wrong. I may, however, be wrong, I just can’t see how the interface would give out.

It is possible the cranks were damaged because the pedals got threaded on cross-threaded. Be very careful when putting pedals on that the threads line up and don’t cross-thread. Put grease on the pedal threads and start the threads by hand for at least a couple of turns before using a wrench (spanner). It can be amazingly easy to put cross-thread some pedals so it is necessary to be careful when installing pedals. Grease the threads, get the threads started by hand for at least a couple of turns, and only start using a wrench to tighten them down when you know the pedal is threading on straight.

Cheaper pedals often have less precise threads than the more expensive pedals. It is possible that your pedals have threads that are just enough out of whack (out of spec) to cause damage to the cranks. The threads may be undersized, oversized, uneven, or very prone to cross-threading. I had one pair of cheap pedals that I had to throw out because they wouldn’t thread on any of my cranks very well.

stealth Torker cranx are alluminum so it would be possible to cross thread them with steel pedal axles without much force.

I put the pedals in tightly, and smoothly, but I put the left pedal on the right side and right on the left. That may have been the reason, and also I think the pedals had steel threads, which may have easily ground up the aluminum cranks. I ordered steel replacement cranks, so hopefully this won’t happen again.



Which cranks did you get?

um… that’d do it. Left and Right pedals are threaded in different directions.

“um… that’d do it. Left and Right pedals are threaded in different directions.”

Well, I’m not much of a mechanic, but I should have figured that out. You should see the wheel I tried to put together with old parts. I tightened the spokes so tight that the rim bent. That was my first wheel building experience though, maybe next time I’ll do better…I hope.


The two main causes of mechanical failure on a uni are:



But with cranks and pedals, putting the left pedal in the right crank will inevitably ruin the crank. (Left hand/right hand threads.)

Putting the left pedal in the left crank, then putting the cranks on the wrong sides of the uni will cause the pedals to unwind - quickly.

I wrote off a brand new crank with that trick.

I think you’ve discovered the problem. That’s kind of like putting oil where the anti-freeze goes, and anti-freeze where the oil goes.

But don’t feel too bad about your mistakes. When you try things, you learn more than if you don’t try them, if you pay someone else to do them, etc. There’s a lot of information on the Web that can help prepare you for future projects, though…