where can I buy new jockey wheels for M900 xtr rear mech ?

[Thias]

I have a battered m900 mech that needs the lower jockey wheel replaced. So I am interested in your judgement, too.

Will or did you replace both wheels? Cos the upper one needs some play along its axle. That's why shimano did not use a ball bearing there. Because of that play, the wheel kind of adjusts to the exact position under the cassette ring. So if the gear index is slightly off, it copes with that. (Was that even understandable? )
The tracx wheels do not seem to have that "feature", right?

 

[FSXStumpy]

While I've not used that particular brand of replacement jockeys, BITD I did dabble with various CNC aluminum pulleys with ball bearings in my derailleurs. Some had an upper pulley with a bronze sintered bushing allowing side-float, and some used uppers with cartridge BB's. Shimano, of course, used a sealed bushing (steel/steel on low end pulleys, and ceramic on high end ones).

I found that the sintered bronze bushed pulleys were trash. They were inadequately sealed. THey quickly wore and began to wobble.

I found that the cartridge BB pulleys worked 95% as well as the original Shimano wheels. They seemed narrower in the teeth than the Shimano units, so perhaps they allowed float by allowing the chain to run slightly off-center on the pulley, rather than the pulley off-center on the bushing.

Ultimately, after experimenting a while, I kept a Shimano pulley on the upper position, and a sealed bearing pulley on the lower. The lower pulley's sealed bearing benefitted from having spacer washers that were as large in diameter as the cartridge bearing itself, when spaced with small washers, the seals never could keep up well. My current pulley's bearing on my primary ride has been in service now for 16 years, and been re-greased only once. Granted, several years had no riding, but it's certainly been up to the hubs a dozen times each of the last 2 summers.

J

 

[xerxes]

Re:

I've used BBB Rollerboys with a couple of older mechs with worn out jockey wheels: http://www.wiggle.co.uk/bbb-bdp-rollerb ... ey-wheels/. They're similar to the Tacx ones, with cartridge type bearings, a set of plastic spacers and no float. The top pulley is thinner, so that the chain can move around instead of there being float on the bearing shaft.

I had a ~1994 XT rear mech with very worn jockey wheels that I couldn't get to shift properly; it would index for the top or bottom 5 sprockets, but not all 7. I replaced the worn jockey wheels with the BBB ones and it fixed the problem and they're still working perfectly and shifting correctly 500, or so, miles later.

 

[FluffyChicken]

Re:

If you ride in mud and water, clean out the Tacx jockies regularly and get some decent grease in them.

They are known to seize up much easier than the lower M900 sealed version.