Back wheel ate my derailleur and bent my hanger pretty bad.
Hesitant to bend it back so far, worry about cracking. Would bending it back hot help or cause more problems?
Steel frame.
by BazamatAgatov
Back wheel ate my derailleur and bent my hanger pretty bad.
Hesitant to bend it back so far, worry about cracking. Would bending it back hot help or cause more problems?
Steel frame.
by BazamatAgatov
6 Comments
Heating it could weaken the steel, especially since you’d probably do it with a torch and would have no idea of the temperature you’re raising it to. Heat treatments and tempering of steel are an exact science.
I doubt you’ll break it bending it back cold.
I’ve straightened worse without heating.
Yeah applying heat will reduce brittle failure
The hot bending temperature for steels vary greatly, and overlap with the annealing temperatures of other steels. So, unless you know what steel that *dropout* is (and you likely only know the *tube* steel, if that), then heating comes with a risk.
Even using a heat gun or hair dryer will help prevent fracturing.. not 100%, but it will help significantly. Just get it thoroughly hot, don’t push it to the point of the paint burning or the metal turning red… just VERY warm….and go super slow with the alignment with s close eye looking out for fracturing.
A blow torch gradually applied before the alignment immediately followed by a dip in ice water if you can gauge temp and are going to paint afterwards. Do some research first though.
Looks like an old surly? I could be wrong, but I’m pretty sure that is 4130… Should be doable, but pretty advanced, risky business.
If I really cared, I would make a “jig” out of scrap wood and use a vice to straighten it vs just yanking on the end. that does, imho (not that experienced) looks like the danger zone where it might be toast. A heat gun might be a safe way to get fractionally more ductility. Chat gpt says 500-700 degrees may help without ruining prior heat treating.