Rear Derailleur adjustment

Apollo748

Hi all,

Wondering if I could ask a bit of advice. Relative newcomer to proper biking so still learning.

I've just had a rear cassette changed from 12-25T to 12-27T along with a new chain at the local bike shop. When I got it home I had a quick ride and it seemed to have trouble getting into a few of the gears and it wasn't running as quietly as it was before.

Being new to these things I thought it might just be that the new chain and cassette needs running in a bit and then the gear changing would sort itself out but not being sure I thought I'd get it up on the trainer and see if I can't get it running a bit better anyway.

Looking at it I don't think it's set up properly, with it on the smallest ring up front and on the back the rear mechanism seems to 'fold' all the way back so that the chain is now rubbing along the bottom which to me doesn't look right. Should it be like this? If not is there a simple adjustment I can make to fix it or, as I suspect, does the chain need shortening?

Rear:


Below:


Side:

nicklouse

not a combination you should really use.

chain length sizing is around the two big cogs without the mech and add one full link.

have a look on Parktools. linky below.

http://www.parktool.com/repair/readhowto.asp?id=26

robbarker

Make sure your chain is properly sized (it doesn't look it):

http://www.parktool.com/repair/readhowto.asp?id=26

Adjust your rear derailleur:

http://www.parktool.com/repair/readhowto.asp?id=64

Job jobbed.

Apollo748

Thanks all.

Back to the bike shop tomorrow then. Bloody hate this sort of thing, I take it to a bike shop specifically so I can feel confident that it's been done properly and won't bugger up mid-ride, rather than the half-arsed job I'm likely to do myself! So annoying. :?

myqul

If your chain rubs when on small/small its too long