When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Bent Crank Arm

-

JohnMast

Look Ma, No Hands!
Hi, Anyone have experience straightening a bent crank arm like this? It's from a 50's Columbia. I'd appreciate any suggestions or ideas.
Thanks!
IMG_2669.jpeg
IMG_2672.jpeg
 
I was hoping to get some advice as i have a blackout crank in nice shape and a little harder to replace .... any info for the BEST way to get it straight as possible this is bike and crank

76E5150E-7ADD-4D9B-9D84-4F9CBC5596CA.jpeg


5BD56187-5834-4699-BA80-EF779315081F.jpeg
 
Somehow setting it up on a hydraulic press is the only way I can think of.
How does something like that even happen? Do whatever it was in reverse. ;)
 
The exact thing happened to my 46 Columbia. I was having a problem with a pedal. I thought it was bent. The crank arm was bent, not the pedal. I removed the crank assembly and noticed the arms were offset, just like yours. I heated it up with a torch and tried to straighten it. I ended up tossing it and replaced. Either someone really heavy stood on the pedals, or a car hit it. Just replace it.
 
I think that method was first introduced in West Virginia back in May of 1931. A loaded log wagon was used verses a van though. A little fine tuning can be done with a 20# sledge.
 
I would clamp it tight in a bench vise with brass jaws to keep it from getting marred, and then heat it at the crank/axle juncture with a torch to an orange color and carefully bend it back. You can slip a piece of steel tubing over the crank for leverage. As long as you keep the heat right there at the juncture you shouldn't have any problem with keeping the axle concentricity intact.
 
Back
Top