hjoe1112

Had a mishap yesterday on my Trek Lexa S. The rear derailleur cage snapped and got caught in the upper chain area. Ordered a replacement RD and chain. But looking at the hanger seems severely bent. Can I bend this back so can be reused safely? Or do I need to order a replacement also?

TakingMyTime

The exact same thing happened to one of my bikes last weekend. One of the kids was riding it, shifted too fast and the chain got sucked up between the cassette and the wheel. Mine looks bent like yours. I'm going to give it a try bending it back. I figure, what do I have to lose? Also after the major bend I'm going to go and by a park alignment tool for the final tweak (I've always wanted one of those tools).

hjoe1112

It seems to bend fairly easily but wondering if it won't be strong enough dyer the stress and break off more easily.

rpenmanparker 

The problem is not bending the hanger back, it is bending it BACK. Or put another way it is about getting it right. Even a slightly bent or offline hanger will totally foul your drivetrain running and shifting. You need a precision adjustment tool to get it right like the one offered by Park Tools. If you don't want to buy that, take the bike into your LBS for a repair and adjustment. They will tell you whether the hanger can be saved and can set it right for you if so. Otherwise they can get you a new one and install it properly. Without the calibration/adjustment tool it just isn't worth trying to do it yourself.

Oh BTW, did I mention I happen to have a brand new, never used Park derailleur hanger adjustment tool that I have decided not to keep? PM me if you are interested. $60 delivered.

smarkinson

The hanger is supposed to be the weak link and replaceable. However, repeated bending makes it even weaker. This could lead to it snapping at an inopportune moment (say changing gears under a hard load) which can send your rear derailleur into your rear wheel ripping spokes and doing more damage.

Its a risk. You may have no problems with straightening but if you do have a problem it could be expensive.

velociraptor

You can definitely bend it back perfectly with the PT alignment tool.

But it won't stay in alignment for long. After ~500 miles, it will need to be aligned again.

This interval will decrease with every re-alignment.

That said, I have the tool, so I generally push my hangers until it's clear they are done.

Just make sure you order a couple spare hangers so you won't have any downtime.

TimothyH

I'd get spend a few dollars and get a new one. -Tim-

BarryVee

Not every hanger bends back, some snap. Hangers are light and take up little space so why walk? I carry a spare though doesn't look like that would help in this case.
If your LBS doesn't have one, nice hangers are available from Wheels Mfg Derailleur Hangers

UnfilteredDregs

Get a new hanger, unless you enjoy **** shifting.

woodcraft

Interesting- IME, the hanger either breaks while attempting to bend it back,

or is theoretically more susceptible to breaking, (more brittle) but not more likely to bend.

In this case, I might attempt to straighten it, but expect that it would probably break in the process.

velociraptor

I've straightened a hanger or two that was as bad, if not worse, than the one pictured above.

The key is to go slow and use small adjustments with the requisite tool. If you try to get it all in one go, I'd expect it to snap as well.

If the bend is really really bad, you can heat it for a few seconds (moderation is key) with a heat gun which will make it more pliable.

CliffordK

I'd probably remove the hanger, and straighten it on the workbench. Then try it out (final tuning on the bike?). You don't have much to lose.

At the same time, it wouldn't hurt to start hunting for a spare.

There are lots of "copy" hangers out there. I wonder if they meet the manufacture specs, so I might prefer using the bent OEM hanger if it can be repaired.