Have i broken it??? Rear Sprocket...

[boze]

my chain was a bit too loose and came off today when i was slowing down at a junction, it cracked the cover over the front sprocket and i have noticed that when i hold my rear sprocket with a finger on each flat side of it i can wiggle it a little side to side, surely this is not right? am i risking my life riding this thing?

yours worryingly,

Damo

[Steve Lake]

what bike?.....on my srx my rear sprocket is loose, not the sprocket itself, but the carrier, i have replaced the carrier bearing, and the cush rubbers, but it still wobbles nicely, doesn't seem to cause any problems. But your chain must have been very slack to jump off the front sprocket, is the chain knackered?, looks like you might be into a chain/sprocket replacement.

[guest27]

Had a look and a number of the rear sprockets in the shed have a little wobble - only the Triton is fixed solid to the wheel.  The RD5 has a seperate bearing in the sprocket carrier / cush drive and this collapsed - guess it gets twisted and it is a ball race not a 'superblend'.  May be worth checking if yours has a bearing in there - but is it the sprocket that moves or the sprocket and carrier?  Is it all held in place by a large circlip or bolts etc - How much play is there?  Does it slop and then stop when it hits rubber / metal or is it mobile but firm - as if it was held by rubber?

R

[boze]

its just the sprocket that moves i think and it doesnt feel rattly, more rubbery, is this ok then?

im going to get a new chain anyway (this ones at least 22years old) and a new stock rear sprocket and a 17tooth front sprocket (one bigger than stock) but it will be a couple of months till i can afford it. i hope what i have holds out that long!!

Damo

[Frog]

Is there a cush drive in the rear hub?

Frog

[boze]

Is there a cush drive in the rear hub?

Frog

i believe so.

Damo

[pigafetta]

How much movement have you got? Is it rotational movement around the hub or can you rock the sprocket so that its not parallel to the wheel? The first is ok, the cushdrive will allow a couple of mm movement. If its excessive and you can't 'feel' the rubber, your cushdrive may be a bit worn. Its sometimes possible, depending on the bike, to make temporary repairs with bits of old inner tube or rubber washers etc.

Dave B

[boze]

if i am standing behind my bike i can move the sprocket side to side so that the sprocket is no longer parallel to the rear hub. it moves about 3-4mm.

Damo

[pigafetta]

Definitely sounds like cushdrive wear. If you're getting a new chain and sprockets I'd get it sorted first. It'll cause unnecessary wear on your new chain.

Dave B

[guest27]

If they can be got a set of cush drive rubber wold not go amiss - on some bikes you can turn the rubbers around to get a little more wear - bit like turning over a doorstep that has worn - does not last too long but does a job

R

[002]

If they can be got a set of cush drive rubber wold not go amiss - on some bikes you can turn the rubbers around to get a little more wear - bit like turning over a doorstep that has worn - does not last too long but does a job

R

Dont forget to replace the bearing in the cush aswell.

Jethro

[beeman]

srx's knacker cush drives quickly. Try shimming them with thin strips of alloy etc. I do this and they last nearly 20k. (Cush drive rubbers are not cheap to buy). I have done this several times with no problems in fact have just put shims in last thursday.
 

beeman
 

[boze]

heres a video of the problem, you see it best at about 17seconds, also when i pull the chain, is the result due to chain wear or sprocket wear or both?

cheers

Damo

oh aye, heres the video: http://media.putfile.com/rear-sprocket-and-chain

[Steve H]

The cush drive bearing is definately knackered. Remove the wheel and pull the sprocket away from the hub (it may be retained by a large circlip on the outside) . Inside you will find a bearing which needs to be replaced. You will also find the cush drive rubbers which by looking at the video are tired, and the chain definately needs replacing.

[boze]

so where online can i get a cush drive bearing and rubbers? ive got a chain on its way.....

i also HAVE to ride it to get to work, am i taking a ridiculous risk here?

Damo