Bent frame?

expjawa · Jul 19, 2011

So I pulled an old Columbia "61 Special" girls bike out of the garage last night to work on cleaning up for my niece to use. When I got it on the bike stand and started working on it, I realized that the head tube and seat tube aren't parallel when viewed from the front. After studying it a bit, I realized that the seat tube leans off to the right. The bend is just above the top tube, which is low since its a step-thru frame.

Has anyone ever tried to cold-set straighten that sort of thing before? I realize that the logical thing is to part it out and scrap the frame, but this thing is otherwise in decent shape and all there. I was really hoping to be able to fix it up. It seems to me that it wouldn't be much different than cold-setting the rear triangles to respace for a wider hub, at least in principle...

scrumblero · Jul 19, 2011

used to tweak mountain frames all the time, long pipe in the head tube.. long pipe in the seat tube... and 2 guys pulling opposite ways :roll:

course you could get it put on a proper frame table at the LBS, but what fun is that??? :mrgreen:

Anonymous · Jul 19, 2011

What he said ^

Work slowly and drink beer with your helper.

Bend it until you break it...then just replace it.

Only funnin,BUT make sure you dont break any weld joints as you're twisting it back into shape.

BE SAFE

expjawa · Jul 19, 2011

Well, I figured if I tied it to a tree, then wrapped a tow rope around the bent area and yanked on it with my truck... :wink:

No, seriously, I was devising a way to fixture it on the arbor press here at work, and then maybe I could apply pressure right to the center of the bend. That assuming I could come with a mandrel of sorts to distribute the load around the tube.

Thanks for the input!

deorman · Jul 19, 2011

I've put them between fence posts and tweaked 'em back with a digging bar before. Definitely don't do it right at the head joints though. In fact, don't do it at all, I can't afford a lawyer if it fails. :roll: :lol:

C.S. · Jul 21, 2011

With any bent pipe: put the ends on two blocks of wood, with the bulge upwards.
Follow this list and see where it gives:
Put a foot on it and apply pressure.
Stand on it.
Start hopping.
Stamp it.
If it is still in the same shape it's a really strong frame and worth the trouble: use a torch or a hydraulic press. Or anything else you can come up with.

Leave the saddle tube thingie in it to keep that end from flattening.