Rattling noise from low gears on rear mech

[bad boy]

Hi All,

I have only just noticed that the bottom three gears being 1,2 and 3 are causing a rattle noise which after looking seems to be caused by the chain hitting the next rear sprocket above at a point at which the cassette rotates on the free hub.

Ive only just noticed as I dont really use these gears. Its not the indexing as its not trying to change gear its just hitting the sprocket above slightly.

I did try relaxing the tension which helped but affected the overall indexing. I can see the problem is when spinning the wheel the cassette does not spin straight on the free hub its almost like a buckle wheel it sort of wobbles very slightly which is causing the chain rattle on those low gears.

It does not do it on the high gears at all.

 

[accountantpete]

I presume the wheel is true? If it is then:

If the cassette is the type where sprockets are fed onto the freehub (and not in one block) then I'd take the cassette off,give the sprockets and spacers a good clean and then make sure the lockring is sufficiently tightened on replacement.

By the sound of it either the sprockets were not seated correctly or a bit of muck has worked it's way in - otherwise you need to be looking at the freehub or the integrity of the sprockets themselves for any problems.

 

[bad boy]

I presume the wheel is true? If it is then:

If the cassette is the type where sprockets are fed onto the freehub (and not in one block) then I'd take the cassette off,give the sprockets and spacers a good clean and then make sure the lockring is sufficiently tightened on replacement.

By the sound of it either the sprockets were not seated correctly or a bit of muck has worked it's way in - otherwise you need to be looking at the freehub or the integrity of the sprockets themselves for any problems.

The wheel is pretty much spot on laterally, but would that not be independent of the cassette ?, im confused...

I will take off the cassette and give it a clean, I did try and move the biggest sprocket and can wiggle it slightly with the my fingers so it might be loose.

I dont have a chain whip so will need to borrow one to have ago.

Thanks

 

[davidg]

what ring are you in on the front?

 

[bad boy]

what ring are you in on the front?

middle ring but it does it on all front rings

 

[accountantpete]

The wheel is pretty much spot on laterally, but would that not be independent of the cassette ?, im confused...

I will take off the cassette and give it a clean, I did try and move the biggest sprocket and can wiggle it slightly with the my fingers so it might be loose.

I dont have a chain whip so will need to borrow one to have ago.

Thanks

If you can move the sprocket by hand then the lock ring isn't tight enough and some grit may have got between the sprockets and the spacers.

Any old chain held in a vice or pliers will do to hold the cassette whilst you undo the lock ring.

 

[bad boy]

If you can move the sprocket by hand then the lock ring isn't tight enough and some grit may have got between the sprockets and the spacers.

Any old chain held in a vice or pliers will do to hold the cassette whilst you undo the lock ring.

Sorry what I should of said is I dont have a chain whip and the tool to undo the lock ring aswell.

Ive been reading previous posts about cassette free-hub wobble and it seems to have caused some debate.

Some people say its normal or acceptable as long as it does not affect shifting and some say otherwise but nearly all posts mention a bent axle as a possible reason why. I did think I had a bent axle a while ago when noticing the oscillation of my disk rotor and do think this is the cause of the wobble in my case. To be honest that back wheel has caused me no end of problems recently whether it be the rim trueness, the hub and now this.

I reckon my hub wont last much longer especially if the axle is bent so ill keep my eye on it and change it after the winter hopefully.

 

[Tollers]

Sorry what I should of said is I dont have a chain whip and the tool to undo the lock ring aswell.

You are welcome to borrow my chain whip if you need to, however i think my casette lock ring tool is only campag. You can pick a shimano one up for about a fiver though.

Tollers

 

[swee'pea99]

Just a thought, but this is quite good and might be helpful:
http://bicycletutor.com/adjust-rear-derailleur/

 

[bad boy]

You are welcome to borrow my chain whip if you need to, however i think my casette lock ring tool is only campag. You can pick a shimano one up for about a fiver though.

Tollers

Thanks Trollers, although I really should buy my own.

Only reason why I dont is with me being slightly ocd if I do buy the tools the bike will be bits after hearing the slightest noise !!