Saving this bent Marin team derailleur hanger: How would you go about it?

[tweedi]

As some of you know I found a marin team (or maybe team issue since most parts are xtr) to be restored. I've been looking for a while and they're not easy to come by so took my chances with this one. Overall the frame is in good shape, a minuscule dent almost inivisble, a desoldered bottle holder thread (still have the part can fix it) and some surface rust. Now there is also an issue with the integrated derailleur hanger. See photos here:

https://imgur.com/a/MUehY23

To the naked eye dropout seem fairly aligned, there is 138mm between the, and the hanger is fairly in alignment with the frame too. The issue is how far back it is bent. From what I see online it's supposed to be straight and not kinked backwards.

I will try and straighten it and if it breaks so be it, the bike was cheap. But of course the ideal outcome for me is that it straighten without breaking in which case I would rebuild the bike completely. Also, I do have a welding kit to with a flame hot enough to braze on steel (can't weld well, but can be used to heat, unless you don't recommend this). How would you approach this? What do I nerd to know to max chances of success?

Thanks a lot!

 

[Rotorhead]

Can you show us a side picture to see this “kinked backwards”.

 

[mdvineng]

I see the bent picture when you click on the photo.

that will require heating to cherry red for re bending or fracture is most likely and then if it doesn't it will be weakened.

 

[Caj Remtiw]

Have someone stand over the frame upside down (like in your picture) and brace it between their legs while gripping both chainstays ( keep that axle in the picture tight in the dropouts). Then grab as large Crescent wrench (adjustable wrench) and tighten it ONLY on the derailleur "nub"... then bend it straight! Be careful not to go to far, it will probably be easier than you expect!

Good luck!

 

[legrandefromage]

I fixed this Rockhopper frame by fitting a rear wheel (or hub) and a bolt in the derailleur hanger to protect from ovalisation and then went about it with adjustable

the hanger was very bent, almost all the way round were the mech had gone into the wheel, it was malleable enough to bend back without much fuss

 

[tweedi]

Thank you both, really helpful reading about your experience.

I can take a spare hub and quick release and lock it in the dropout. Will it be an issue if the quick release is clamped in the dropout I'm working on (bending the hanger back forward whilst there is a clamped qr in it)?

Also, would using a steel tube to "pry* the hanger easier than an adjustable wrench?

Seems I would go the "cold" route based on your experience.

Good shout on the screw in the hanger thread.

 

[Caj Remtiw]

Also, would using a steel tube to "pry* the hanger easier than an adjustable wrench?

No! You want to align the "flats" and front of the wrench perpendicular to your "bent line" then pry. I've done this maybe a dozen times over the years and they all have turned out killer!

 

[bikeworkshop]

As @mdvineng says, you need it Cherry red. If you have a blow torch or something a little hotter.
At that temperature, the steel becomes many times more malleable.
(I do this professionally)
You could try without heating, but the chance of success is massively reduced.
Burning the paint is a small price to pay, and you can wrap a damp cloth around the stays an inch or 2 away to limit the damage.

You'll also need to keep the threaded derailleur fitting from distorting, or reform if its ovalised already.
Sometimes I'll fit a derailleur mounting bolt into the hole and tap it back into shape when it's proper hot if it's been pulled open in the accident.
Sometimes you can protect that area from bending by gripping beyond it to apply the bending force.

Desperate measures, but saves a more complex repair if you tear the hanger or get a horrible shape.
Replacing a hanger is a pita

 

[eshew]

I'd agree, heat would be ideal. You're already set up to apply it. A 10mm rod or spare hub would be better than a QR.

 

[hamster]

I've managed to recover it even when the hanger was bent so far that the mech was upside-down! Definitely heat helps.

A framebuilder would happily take on this work, along with setting the alignment and frame tracking.