Straightening a chainring?

yoothgeye · Mar 8, 2011

I was looking through my junk yesterday and I pulled out a nice 1 piece crank off the old GT BMX I was given. The chainring is a 2 piece alloy unit, a disc inside and then the chainring outside. The bike was run over at some point and the chainring has a slight bend in it.

I don't have a vice with a wide jaw to try to bend it back, but it's so slight a bend that I'm afraid if I tried that I might bend it into an "S" shape.

Anyway, I dropped it by a friend with a press at work and he is going to try to sandwich it flat, but will the alloy just spring back when the press is opened or stay flat?

No matter what happens, the ring was unusable as is, so any attempt to fix it won't hurt it.

yoothgeye · Mar 8, 2011

I don't know what he did, but his daughter just brought it by the house, and it's flat now. I gave it to him with the ring and center separated and gave him the hardware to hold onto. It was delivered back together. Once I started thinking about it, it's good he assembled it because if the ring and or center are still off a bit, but putting them back together not the way they were originally the natural bends will fight against each other. Now I get to take it apart, clean and polish the outside and paint the inside and figure out what I'm going to do with it. Here are the after photos, since there are no before photos you can just imagine it bent.

Little wave in the center section that can't be captured on camera, but won't affect performance.

Was trying to show in this photo that on a completely flat and level surface all the bolts touch evenly.

And yes, it's smaller than a bread box.