What IS this noise coming from my rear derailleur?

mikkybgs

I am being driven mad by a mystery noise coming from my rear derailleur area and was hoping someone may be able to shed some light on it's cause.

I have made a short video with the noise to help clarify because describing a sound isn't the easiest thing to do, but essentially it a gravelly/crunching noise.
It can be heard here: http://youtu.be/vmxf5qM06zE

It is a relatively new bike, only about 2 months old and despite me getting it fairly muddy I've always cleaned it properly using muck-off and kept the chain lubed.
The noise could also be described as a bit 'clicky' and after spending literally hours trying to work this out i have noticed (although this could be because i'm just noticing things i'd never paid attention to before) that when the chain is going on and off the cog (not sure of the specific name) it is ever so slightly aligning itself and ticking/clicking when it is getting on to or getting off - i realise this is a awfully phrased sentence.

At first I thought it was the chain needing lube but i completely lubed it and it still creaked to i removed the chain and thoroughly cleaned it but the noise still continued.
I also thought it may be coming from the freewheels but when the chain was removed i tested all this and the cog on the wheel and these were all free and easy.

Is this even a noise that was always there and i've just discovered it and started obsessing? It seems too prominent to be nothing though and i'm sure i'd have noticed it before now.

Anyway, any help would be gratefully received and would help stall me going completely maddddddddd...........

nicklouse

is that back pedalling?

sounds normal to me.

mikkybgs

Sorry yeah should have mentioned, back pedalling it is.

Really? I'm a bit gutted to hear that. I almost want to find a problem now after wasteing so much time....

mikkybgs

Should it not really just be the 'tick tick tick' of the freewheeling hub?
The recording isnt great quality but there is a different sound also....

nicklouse

you will get some noise from the chain and mech as it is all going the wrong way.

mikkybgs

Ah yeah it does make the noise going the correct way though. I just did this so i could record it while it was on the ground.....

The first time i remember hearing it was after the bike got completely filthy and i really thoroughly cleaned it....

mikkybgs

I just went to test it again to make sure i wasnt just imagining it and it it much worse in certain gears, for example the second biggest gear ring on the back is much louder than the rest, regardless of what gear the front derailleur is in...

cooldad

Indexing needs a bit of adjustment?

nicklouse

time to take it in for its first service.

could be the tension try adding a 1/4 turn to the cable.

see parktools.

spuddle

have you got the chain correctly routed through the derailleur? sounds like its rubbing on the little plate between the 2 side plates.

mikkybgs

Thanks for the replies.

I continued the fruitless task of tinkering with it for the last while and the suggestions of the indexing were closest. Or at least, they helped the problem the most but there was still the slightest ticking which was driving me bonkers.

Anyway, it got too much, I had to see if I was going mad and took it into my LBS who quickly diagnosed it as a bent rear derailleur hanger.

All fixed now and I can return to sanity........ :shock:

andhr

I have this on a week-old bike, going to play around with the indexing as it only appeared yesterday - if it's not that then the hanger seems to be be the next culprit and I can't really figure out how thats bent already...

mikkybgs

I wasn't sure how I'd bent mine either as I was pretty sure I hadn't banged it on anything but the chap in the shop said sometimes they can come bent, or more precisely not be aligned properly on the bike and cause the ticking which I was experiencing.

I'd play around with the indexing first and failing that then check the hanger.