For Shimano

NOTE: THESE JOCKEY WHEELS ARE FOR 12 SPEED REAR DERAILLEURS. If you have a 10 speed rear derailleur we sell those jockey wheels under eBay item 260823214178ACER 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. Lightweight removable red aluminum covers protect the ceramic ball bearings further from the elements while giving a more aggressive appearance. The ceramic bearings are not lubed as they are designed to run dry for maximum speed. Lowering your rotational mass is extremely important when racing. Reducing weight off parts that actually move or rotate such as wheels or jockey pulleys have a much greater effect on performance than removing an equivalent weight off a part that is stationary such as a lighter bicycle frame. That is the design concept and philosophy behind our carbon fiber jockey wheels. They are light enough to have a significant impact on acceleration while decreasing friction. Our ceramic bearings inside further compliment the lightweight carbon fiber design by lowering rotational mass and offering the friction free performance we have been known for since 1989. Lower your rotational mass for quicker, smoother acceleration and higher speeds with less effort with our remarkable new ceramic jockey pulleys. PRICE IS FOR TWO PIECES AS SHOWN IN PHOTO.