Is my Rear derailleur bent ?

JamesFree

Have just bought this second hand dura-ace mech and having a few problems setting it up and have also noticed that from behind it looks bent, comparing it to my other bikes it doesnt look normal, please advise.

It has had a carbon cage added by the previous owner


Thanks

JamesFree

It would appear its definitely bent, as put on my old mech and it goes straight down.

Grrr how annoying, hope the guy is kent enough to refund me !

Monty Dog

You'd be going some to bend a mech outwards - they usually get pulled inwards or crash-damaged. Perhaps the carbon cage had been installed incorrectly?

fludey

Not easy to tell from pic but are you sure it's bent as it doesn't look like it's lined up properly by way of cable set up :?

rothers_bikeo

Almost looks like it's cross-threaded in the hanger to me.

SteveR_100Milers

rothers_bikeo wrote:

Almost looks like it's cross-threaded in the hanger to me.

Yep, or the hanger is also bent. I have the same problem with my new bike - it doesn't take much distortion in the hanger to push the whole thing out of alignment. What does it lok like from behind? i.e is it out of alignment in more than one axes?

JamesFree

Hanger is fine as just put on my old mech and its 100% straight

Its wierd as the cage is flush to the body of the mech but it almost seems twisted definitely not right.

I bought it from a guy on here so hopefully he will refund me when i get it back to him

mcj78

Did you solve this? I only ask as my rear mech recently took a detour through my spokes (low speed thankfully) & bent the hanger, I replaced it, but now the shifting on the top half of the cassette seems decidedly "off" - checked the dropouts & they look straight, under close inspection though it almost seems as though something in the body of the rear mech has twisted slightly - the cage looks straight but isn't hanging 100% vertically but the mech itself looks perfect, gonna remove it & try to straighten it & see how that turns out, digits crossed - hope you got your problem resolved anyway!
J

ratsbeyfus

mcj78 wrote:

I replaced it, but now the shifting on the top half of the cassette seems decidedly "off" - checked the dropouts & they look straight, under close inspection though it almost seems as though something in the body of the rear mech has twisted slightly - the cage looks straight but isn't hanging 100% vertically but the mech itself looks perfect,

I had this problem for months... indexing impossible to set-up properly. I gave in and took it to a mechanic, expecting to be told hanger was bent, but after checking with their alignment tool they worked out the derailleur was bent and needed replacing. Probably worth going to your LBS to get it looked at.