The SRAM Black Box ceramic derailleur pulleys are made of the same material as the standard pulleys, but they use polished stainless steel races and ceramic ball bearings in a sealed unit. The pulleys are a bit lighter and more durable thanks to the ceramic balls, but more importantly they have substantially less drag than standard stainless steel balls. And they can be taken out and re-lubed if your heart desires. These pulleys should outlive your bike, provided your chain is cleaned and replaced when it should, before the stretched gritty chain wears down the pulleys. Features: • The SRAM Black Box ceramic derailleur pulleys work with the 2008 SRAM X.0 rear derailleur. • The upper jockey wheel spins on a shaft that goes through the jockey cage pivot point. • Weight for the pair is 24g.
Rated 1 out of 5 by Mountainman1 Wears out quickly
As other reviewers I found these to wear very quickly - I remove/clean and lube my chain frequently so not sure how they could wear out in a few months. The wheels do spin very freely but the poor longevity and their cost to replace makes them a very poor purchase
23 January 2014
Rated 1 out of 5 by Anonymous Overpriced and poor wearing
Same as other reviewer. Had these on my X0 mech. Lower wheel wore badly after 4 months and that was with a chain still in good condition. Replaced them with some £30 ceramic bearing metal wheels.
You can buy a new X0 rear mech for around the same cost! What's the point in buying these?!?!?!
17 February 2012
Rated 1 out of 5 by Anonymous Wears out just as fast as cheaper jockey wheels
I had these as oem on my bike but they wore out (contrary to CRC's description) a LONG time before the chain needed replacement.
I certainly wasn't going to pay more for a pair of jockey wheels than I had for a new pair of tyres for my car.
Eventually found compatible Tac-x wheels
29 December 2011