Rear sprocket wobble

[pipsovich]

Hello!

Almost done finishing my project here, which uses R6 wheels.
I have a bit of wobble in the rear sprocket, when rotating the wheel on a stand, it wobbles about 0,8-1 mm.
It is NOT the sprocket, because i have removed it to measure the mounting face of the sprocket carrier, and it also wobbles.
It seems to be the cush drive, because if i remove the carrier and install it at another place, the point where it wobbles the most changes.
Wheel is also straight.

Should i try to fix this, or is 1 mm wobble ok? The bearing in the sprocket carrier i also good.
Feels like if the cush rubbers arent seated correctly, the bearing will wear a lot faster? Thats not a really big issue for me, i just dont want the chain to snap when im driving.

[Overlord Neil]

'Wobble' is a fairly ambiguous term, its hard to give a definitive answer as the 'rate of wobble' will also have an impact, if the sprocket carrier is flapping about like a dick in a bucket the fact that you have only 0.8-1.0 of movement will be irrelevant, thats way more than the bearing will be comfortable with. If the sprocket carrier is taking up slack in cush drives you might be ok.

Depending where you are measuring the deflection, by the time you get to the outer edge of the sprocket that 0.8-1 could be 3-4, ride the bike pretty hard and I reckon you could be in a bad place. Chances are it will be fine but if it does go at best you'll be pissed you didn't get it fixed when you knew about the problem.

[pipsovich]

Im sorry about the terminology, im from sweden so i tried to explain it to make you guys understand.
The face of the sprocket carrier wanders 1 mm with the wheel mounted and the sprocket and studs removed for easier measuring.
I would never ride the bike if the sprocket was wobbling 3-4 mm.
Im going to put the sprocket carrier in a lathe to be able to measure it better.

[cobbadiggabuddyblooo]

Replace all 3 wheel bearings and the Cush drive rubbers and you'll know you won't have to touch the rear wheel for quite some time.
I replaced the old tired Cush drive rubbers on the std trx rear wheel and it was quite evident how much damping I had lost with the old rubbers. The clutch Hub would wobble a little in the wheel and could be easily removed with the old rubbers in place. With the new rubbers, the clutch hub needed my full body weight with a good push to get the clutch hub to seat correctly into the wheel.

[Overlord Neil]

No need to apologise, I wasn't picking holes in your English, I'm always amazed by how well non-native English speakers get the nuances and quirks of English. If I was trying to get my point across on a foreign language forum I'd put EVERYTHING IN CAPITALS AND USE BIGGER SPACES...

[pipsovich]

Thanks for more answers guys,

I have now placed the sprocket carrier (Which is from a R6 2006 btw) in a lathe and used an indicator gauge to check it.
It "wobbles" 0.15 mm, which i must believe is ok. Kind of hard to measure it, i used and axle put into the bearing, which is not optimal as i get the bearing's play into the measurement. Best would be to make a new axle, with the same OD as the bearing, press it into the lathe, and then measure it.
I then tried assembling the rear without the cush rubbers, and what do you know - with sprocket on, the wobble is about 0,2 mm at most, measured at the edge of the sprocket. (cant measure it that good, but 0,2 is exaggerated).
The rubbers are very tight, i have to use much force to get the carrier on.
Would you ride it like this?
I have googled and found people that has got 3-5 mm, which is not ok, some say 1 mm is fine, and so on. Cant trust anyone..

Hehe i hope my english isnt that bad, we have very good english education here, and i have also taken technical english courses during my engineer education.

[Mincehead]

A sprocket must `float` in as much as the cush drive rubbers allow it to move.
The run-out you`re talking of is minimal, 3mm is perfectly acceptable as the chain, if correctly adjusted and the wheel aligned will pull the sprocket to run straight with it.
Ok, I get the lateral run-out will add a little to chain wear (perhaps), but not lubricating a chain or having it running out of alignment will be far worse in respect of chain life.
The cush drive rubbers should grip the carrier webs tightly, any play in them or degradation along their edges means that they need replacing. Chain lube and grit is the killer for cush drive rubbers, too many folk don`t lube their chains carefully enough.
Oh and your English?
A damn sight better than my own at times.

[Overlord Neil]

SHOULD BE FINE