Why take apart a perfectly good Record or Dura Ace rear derailleur and install aftermarket Ceramic Speed pulleys? It's easy: Unlike aerodynamics -- where only the fastest riders enjoy the advantage -- ceramic bearings offer their most distinct advantage when you're pedaling at lower speeds. This is a crucial difference between aerodynamic resistance, which increases exponentially with speed, and mechanical friction, which increases in direct proportion to speed. From a technical point of view, riders sheltered inside the peloton have more to gain with ceramic bearings. To wit: Dura Ace pulleys consume 0.78w at 500rpm, while Ceramic Speed ceramic pulleys consume only 0.06w.

These use Grade 3 ceramic balls: equal or better in quality than any other ceramic product sold in the marketplace today. Choose Shimano or Campagnolo, based on your rear derailleur brand.