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Bent chain stay - possible to bend back?

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Bent chain stay - possible to bend back?

Old 03-20-21, 03:25 AM
  #1  
jliet
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Bent chain stay - possible to bend back?

Hello,

This is being sold and was wondering how safe this would be to try and fix/bend back - it is a 531 steel frame, and the bend was not from impact, but from a coaster brake (gone wrong, I guess)?

Cheers.

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Old 03-20-21, 06:26 AM
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Originally Posted by jliet View Post
Hello,

This is being sold and was wondering how safe this would be to try and fix/bend back - it is a 531 steel frame, and the bend was not from impact, but from a coaster brake (gone wrong, I guess)?

Cheers.

given thatís itís steel, if the price was right Iíd certainly take a swing at it. Should be doable with a little forethought, a bench vise and some wood blocks. Looks like both the chain- and seat stay are bent, so I would alternate between the two to slowly rotate the dropout back down. Might need some tweaking to ensure correct wheel alignment. And a second pair of hands might be useful

Last edited by Litespud; 03-20-21 at 06:29 AM.
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Old 03-20-21, 09:55 AM
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Unless the frame was being sold for less than $10 USD, I'd pass. Even then I consider how easy I could find another frame with no issues..

However if it were mine, and steel, I'd try bending it back into whatever it took to make the dropouts aligned. I wouldn't try for perfection.
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Old 03-20-21, 03:42 PM
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Should be safe afterwards, and at least with steel you should be able to see evidence before it fails. I would think you could use a framebuilders jig and get it able to be ridden if not looking perfect.
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Old 03-20-21, 03:59 PM
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My lbs has the park tool SS-1 stay straightener and has straightened a chain stay for me. That bend is very close to the dropout but it would still probably work. Your lbs could also give you an opinion on the repair.
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Old 03-20-21, 06:14 PM
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I had bent seatstays that were worse than that. I had it straightened and rode the bike three more years, until the brazing at the seat lug cracked. That's when I sprung for replacement and a respray.

The chainstay is bent too, but I would certainly have this straightened and keep riding it, or sell it. If the tubes aren't creased, they is still stronger than the joints it's brazed to, and there's a lot of joint contact at the dropout, unlike a standard seat lug.
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Old 03-20-21, 06:44 PM
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Some good and less good advice here. I would not use a builder's jig, that's not the jig's purpose and there are faster methods to check alignment as the bending is going along that cost MUCH less. I would do some of the chain stay then some of the seat stay and back a few times to "walk up to" the best final outcome. Fr the best visuals you want to focus the bending focal point to where it is now. The Park tool really won't do this as well as clamped boards will, I have done a combo before though with metal channel clamped to the stays to better locate the bending point. Andy
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Old 03-20-21, 08:54 PM
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It doesn't look like too difficult of a fix. A large C-clamp and some strategically placed blocks of wood, and you could have that straightened out in no time.
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Old 03-21-21, 08:52 AM
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I'm looking at this and thinking it's a little more complicated than just straightening the chain stay as the seat stay is also bent at the dropout and maybe the CS is bent at the BB shell too. Personally I would take it to a pro for an estimate before making a worse mess of this mess. Might not be hugely expensive and well worth the money spent.
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Old 03-21-21, 06:13 PM
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I've straightened worse stays than those using 2 wooden blocks under the stay, 1 on top of it and a lever, with the frame on the floor and using a heavy workbench as a stop, and they came out well.
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