Do I need a new Dérailleur hanger?

[DWiggy]

I recently changed my chain from an SRAM to a Shimano 105 (Same as group set) and all seemed fine with no jumping gear changes so managed to get another go out of the rear cassette.

I had a small off around a month ago but bike didn't seem to damaged at the time, although since then I'm having difficulties getting the gears to shift throughout the cassette smoothly.

For example the gears change perfectly from the smallest to around 4th or 5th but any higher the changing becomes clunky, noisy (clattery) and the chain cant make up its mind what gear its in.

I have followed many online tutorials but all fail with the same annoying result, so I guessing either a new hanger is required or I need to get the dérailleur hanger aligned?

Has anyone else had this problem and how did you manage to fix it?

Many thanks
Dave

 

[SpokeyDokey]

Yes, week before last. Minor off due to diesel spillage on road and some twonk decides that buckets of water was a good idea.

Shifting (105) was a tad ratty - not major but definitely not slick.

Hanger bent slightly - LBS straightened it in a jiffy.

NB: it wasn't readily apparent to the eye that it was bent but the straightening tool showed it to be well out.

 

[andrew_s]

Straightening tool

If you have a replaceable hanger, it's probably worth getting a new one before having a go at bending the old one straight (or allowing the LBS to try).
Bending would usually be OK the first time round, but breaking the hanger off is possible, and would render the bike unrideable. Hangers tend to be different for each model of bike, and sometimes between different year's versions of the same bike, so the chances of the LBS having the correctc hanger in stock are relatively low.

 

[DWiggy]

I was thinking of replacing the hanger altogether as its only £15 for my bike, and i'm guessing the LBS will charge around the same to straighten the old one.
Cheers for the advice.

 

[DWiggy]

Went to my LBS they told me its not the hanger that's bent its the cage on the Dérailleur!!!!

 

[DWiggy]

Installed new 105 Dérailleur and cables and the bike feels like brand new!! very please with the results, comparing the two the old one was definitely broken the cage was quite twisted but it wasn't obvious unless side by side!