NOTE: THESE JOCKEY WHEELS ARE FOR 12 SPEED REAR DERAILLEURS. ACER Racing presents our 13 tooth Carbon Fiber Jockey Wheels with Ceramic Ball Bearings for Shimano. The gears are made of super stiff and lightweight 7075 Aluminum and we include our World Champion ACER Racing Ceramic Nitride Pro Series ceramic ball bearings with dual seals in each jockey wheel.
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