Bent top tube - rideable?

[sjcprojects]

I have a 531 frame which has taken a knock (not a crash) resulting in a bent top tube.

This photo shows where the dent is - it's not easy to show the extent of the bend, but it's most obvious on the right where it bends inwards. Both ends of the tube are not actually that far off each other in alignment (judging from the ends of the lugs on the top of the tube), so I'm wondering if this is ridable as it is? Is that a stupid idea? Structurally I think it's fine, but will it handle weirdly? Should I just build it up and see? I would fill in the actual dent, if so.

 

[novocaine]

get it on a jig and straightened.

 

[legrandefromage]

get it on a jig and straightened.

And the frame too?

 

[novocaine]

And the frame too?

no need for a jig to sort that, just keep pulling it. It will either go straight or splatter everywhere and return to flaccid.

 

[3wheeler7]

I think with a few blocks of softwood and G cramps the bend would pull out, you'll still be left with the dent but - as you say - that could be filled.

 

[sjcprojects]

I think with a few blocks of softwood and G cramps the bend would pull out, you'll still be left with the dent but - as you say - that could be filled.

I guess it's worth a try. So, put the top tube between two blocks of wood and clamp it down to straighten it? I'm not sure I can visualise it...

 

[novocaine]

I guess it's worth a try. So, put the top tube between two blocks of wood and clamp it down to straighten it? I'm not sure I can visualise it...

I'd put a block at either end with a straight bit between then a block on the other side with the clamp across the middle.

 

[sjcprojects]

Thanks for the thoughts. I have a not particularly solid g-clamp I could try and use, but I will also have access to a vice at the weekend, which could maybe work with thinner pieces of wood. There's no harm in trying anyway, I suppose.

 

[novocaine]

Thanks for the thoughts. I have a not particularly solid g-clamp I could try and use, but I will also have access to a vice at the weekend, which could maybe work with thinner pieces of wood. There's no harm in trying anyway, I suppose.

You can't **** it more than it already is.

The tooling we used were very heavy steel with rubber feet Normally used to pull motorcycle frames straight but I got to do few bits on the side. Normally the frame was held a jig.

 

[sjcprojects]

Yeah, getting the frame to stay static while pushing the top tube inwards is going to be a challenge - it's not going to be straight-forward. Still, it'll be a learning experience, whatever happens...