Bent Derailleur??

LordBanks

When looking at my Derailleur from behing, the top jockey wheel is nearer to the wheel then the bottom jockey wheel.

Is this bent, or do i need to adjust them screws to line it up??

steelo

From my experience the rear mech jockey wheels should be directly in line along the vertical. Take your bike to the LBS and they should be able to put a 'rear mech alignment tool' on the mech hanger and bend it out straight again.

Or you could just buy a replacement mech hanger for <£20 and replace it yourself.

Either way the mech will then sit correctly and gear changes will be smooth(er) again.

allthegearnoidea

bit of both!
i noticed on wednesday that from above looking back my rear mech was quite twisted! straightened it up when i got home so it sits properly now, makes things a lot smoother!

LordBanks

I thought it was probably bent, is it easy enough to bend it straght again??

nicklouse

it is most likely to be the mech hanger NOT the mech, so the adjusters will not improve the situation.

To the LBS for the hanger to be straightened.

LordBanks

Ahhh, right, think i'll take it to the shop, i'd probably end up making it worse. In fact i know i would.

Cheers fellas.

allthegearnoidea

i just grabbed mine and bent it back straight from the jockey wheels section! quite easy to do! (had to do it once or twice before on the old bike)

LordBanks

Reet, i'm gonna have a go meself, had a look and it does seem to be the hanger, if i break it, i'll blame the dog, the missus will never know.

TonyS

Unless you anneal first you will work harden whatever you bend (mech or hanger or both) and the result will likely be a failure point mid ride when you are miles from anywhere,

To straighten a hanger heat with a blow torch to about 500oC then fast cool by droping into iced water (this will hopefull anneal it) then place in a suitable vice to straighten. Repeat annealling process if you need more than one go at getting it reasonably straight. Then order a new hanger, fit and keep the straighten one as a emergency spare.

Mech cages can be fixed using the same process (if Ali of course)

drewp2008

How can you heat it to 500 degrees celsius when you're trying to straighten it? I dont think park would recommend using the DAG-1 in a smouldering hot hanger.

The hanger might be a failure point but its meant to be, hence why its made of soft alloy, as its a cheaper failure point than the rear mech or frame. It wont go mid-ride since its not a great load bearing part, it only goes when you whack the back end.

Furthermore new hangers arent necessarily straight, hence the usage of a derailleur alignment tool of some description in order to check this.

Ryan Jones

The rear mech hanger is like a fuse, helps protect the rest of the (more expensive) parts of the bike. As for straightening it i just got it off the bike and tapped it with a hammer whilst gripping with mole drips and on a brick wall, put it back on and see if it was lined up, then done it again till perfect, worked fine until i fell off yesterday.

By the way how is a mech hanger a stress point? The pressure off the wheel is on the frame and hanger where theres no leverage, hence why hanger and frame overlap.

Salsa

Just take it to a shop as using the correct tool ensures its straight & bends in back in a few seconds with pretty much no effort, I certainly wouldn't just grab the mech & try to straighten it like that.