Jockey wheel sizing - 10 or 11 tooth?

Neutrino

Hi - would appreciate some advice. I'm set up on an 8 speed XT rear mech (99% sure it's this one: http://www.ttsattler.com/m/ebay/shimano ... -14702.jpg). I need to replace the wheels.

I'd like to either go for the standard Shimano replacements or upgrade to Tacx ceramics - I've researched but am getting conflicting advice on whether I can go for 11 tooth replacements, or whether I have to stick to the original 10 tooth (which are getting harder to locate).

Any help appreciated!

drlodge

You should be able to work out if 11 teeth will physically fit or not - is there anything on the jockey cage that would foul with the chain if the jocket wheels are a bit bigger? I would expect any "upgrade" part to list its compatibility.

11 tooth wheels will turn a bit slower than 10 tooth wheels and give an advantage hence the "upgrade" slogan, but I expect the performance improvement to be minimal.

bikaholic

It will work with the following caveat: the 8-speed jockey wheel might be slighty thicker than the 9-speed version. This means that the derailleur plates will be closer together (ie clearance for 8-speed chain will be narrower) when you bolt the jockey wheels on. But, you can add some washers to address this problem.

Using 10T in place of 11T jockey wheels is a well known mod to increase the max sprocket size supported by the RD. This tells you that the converse of the above also works.

Neutrino

Just to say that I'm not going for more teeth as a 'performance' upgrade (I'm no pro rider!) - just that there are fewer options available for 10t, and I figured might as well get the best I can. My XT mech has top ceramic and lower steel bushing - the steel one is more worn/pitted so I thought I'd go ceramic all round.

I take on board the point about change in thickness. Can't find any specs online which show a jump in diameter from 10t to 11t, so it's a bit tricky to see if it will present problems. Looks - by eye at least - that there should be enough room for chain clearance without hitting the top or bottom guide on the cage.

Running a 30t large sprocket… I'm thinking it might be worth a punt, but just wondered if anyone else had done similar.

Thanks for the quick responses...

bikaholic

The BBB RollerBoys jockey wheels is what I would buy as they come with a selection of spacers to fit various RDs.

The 10T, 8-speed versions are available at Wiggle and elsewhere.

Neutrino

Going to go with that 10t option to be on the safe side; cheers for all the advice