Noisy rear derailleur

BDFun

I took my rear wheel off the other day to give the cassette a clean, along with the dérailleur and chain.

Since putting it all back together, there is a lot of noise around the top jockey wheel or cassette area. I've spun the same jockey wheels independently without the chain attached, and they are silent. I'm at a loss as to what I've done that has caused it to go from being silent to this. Difficult to describe the sound, but it almost sounds like rice crispies popping, or lots of clicking as the chain spins forwards or backwards.

Only thing I can think of is that I've used Finish Line Dry Teflon Lube on the chain, which I've not used before.

I've checked the chain isn't skipping on the cassette, adjusted the barrel adjuster in both directions, chain is lubed, jockey wheels are lubed, and that the dérailleur is aligned. Any suggestions?

Pics of it:




My dérailleur looks filthy in these pics, but it doesn't look like that in normal light!

sungod

the gap between the upper pulley teeth and the sprockets should be around 6mm (no less)

in the pictures it looks a lot more

it may not be the cause of the noise, but if the rear mech isn't adjusted according to sram's instructions, you never know, so i'd just go through the full setup process and see if it helps

there's a link to derailleur setup on this page...

http://www.sram.com/service/sram/3,254

Twostage

Could be the lube. Did you give it a good shake before applying ? If not give it a shake and put more on or try a different lube.

BDFun

sungod wrote:

the gap between the upper pulley teeth and the sprockets should be around 6mm (no less)

in the pictures it looks a lot more

it may not be the cause of the noise, but if the rear mech isn't adjusted according to sram's instructions, you never know, so i'd just go through the full setup process and see if it helps

there's a link to derailleur setup on this page...

http://www.sram.com/service/sram/3,254

Thanks, I'll have a look through it and ensure it is set up correctly, but as you say it might not be the cause as it was like that prior to the noise.

Twostage wrote:

Could be the lube. Did you give it a good shake before applying ? If not give it a shake and put more on or try a different lube.

I don't think I gave it a vigorous shake the first time, but I did on my second application. Although with my second application, I just applied it without cleaning the chain as I had only ridden it once, and thought that maybe I hadn't applied enough the first time round.

I'll try reverting to the lube I previously used and see if that gets rid of the noise.

Thanks

smidsy

I use the Finish Line Dry Lube and no such noise. Not sure that actually proves anything but just thought I would point it out.

www.richtreen.co.uk

I second the the chain gap check - same issue here recently of late some annoying chain noise and it was the B Screw, definitely check the gap between the upper jockey and cassette.

BDFun

Hi all,

So I've reverted back to the lube that I used to use, and adjusted the chain gap, and I'm still getting the same noise. It seems to be coming from the jockey wheel at the end of the rear derailleur. I've tried lubing that jockey wheel too.

I made a recording of the sound and uploaded on to YouTube: http://www.youtube.com/watch?v=uD8dClVJMSo

Note that the bike is upside down.

lycraholic

Surely the B screw.

(Also I might be imagining it but the derailleur hanger looks slightly misaligned, that might cause a noise regardless of cable pull)

dabber

All you originally did was take the rear wheel out? Yes?

So other than a bit of cleaning nothing else has been changed? Are you sure the wheel is sitting correctly in the rear dropouts?

You never took the jockey wheels out when cleaning did you? If you did are you sure you've reinstalled the right one in the right place?

BDFun

The only thing I detached from the bike was the wheel, and I've double checked the wheel is back in place correctly. I cleaned everything else in situ.

BDFun

I spent a while tonight looking at the bike, and it's a possibility that the tension jockey wheel (the one at the end of the derailleur arm) is at a slight angle. Perhaps this is the cause. If it is, how do I adjust the angle of just the tension jockey wheel?

jgsi

I'd just do the simple things first..
If the noise is like it is trying to change up or down the cassette... i.e a rattly sound, and the gear changes are not sweet
using the barrel adjuster at the rear mech
slow going up the block - turn adjuster anticlockwise
slow going down the block - turn adjuster clockwise (tightens the cable)

when you drop the rear wheel, are you making sure your are on the inner ring at the front and the smallest sprocket at the back?

BDFun

JGSI wrote:

I'd just do the simple things first..
If the noise is like it is trying to change up or down the cassette... i.e a rattly sound, and the gear changes are not sweet
using the barrel adjuster at the rear mech
slow going up the block - turn adjuster anticlockwise
slow going down the block - turn adjuster clockwise (tightens the cable)

when you drop the rear wheel, are you making sure your are on the inner ring at the front and the smallest sprocket at the back?

When I put my ear up to the area, the sounds are coming from the lowest jockey wheel, so I don't think it is trying to skip gears. I tried the barrel adjuster before, which didn't improve the noise. Shifting appears ok to me. The noise is consistent regardless of what gear and chainring I am on.

As obvious and basic as it may sound, I don't think I switch to the correct gears and chainring (as you said) when dropping out the wheel. Perhaps I knocked something out of alignment when I failed to do this.

Or it could be I washed out the grease in the jockey wheel while cleaning it in situ.

apreading

Are the two jockey wheels the same? You may be able to swap them over and see if it is still the same wheel making the noise?

onbike 1939

The noise mentioned is typical to that caused by a bad chain-line but it's difficult to see how it can be this given nothing has been changed. However best to check by viewing the gear hanger from the rear and checking that it is exactly below the sprocket which is engaged.

apreading

Could it be a bent hanger?

onbike 1939

apreading wrote:

Could it be a bent hanger?

That would cause the fault mentioned but nothing in the OP would suggest this.

bottom_bracket

Have you got the direction of rotation correct on the bottom jockey wheel? not sure if it really makes much difference but my Sram one is directional.

* just noticed OP didn't remove jockey wheels. Oops.

Ben6899

The mech cage appears to be twisted.

rolf_f

Ben6899 wrote:

The mech cage appears to be twisted.

There is a hint of the banana in that mech cage! To OP - how did you park the bike when the rear wheel was off?

bottom_bracket

also - the whole mech appears to be slightly misaligned. Chain runs directly away from the eye, bottom pulley isn't square to the eye as left side is visible.

jonomc4

I had the same problem - to it for a service - as everything was new (including frame) - bent mech hanger was the issue. I do think it is worth a check