With a company philosophy of helping you go faster with less effort, it would make sense that Rotor would offer their bottom brackets with ceramic bearings, like this BB1 Zero Ceramic Road Bottom Bracket. And the combination of the ultra-smooth Enduro ceramic bearings with Rotor's non-contact labyrinth seals puts the BB1 Zero in a league all its own, with regards to how smoothly it spins. And that the ceramic version saves a few extra grams over the steel bearing BB1 bottom bracket doesn't hurt either. Anytime we can have faster and lighter in the same package, we like it.As part of their sponsorship commitment with the Cervelo Test Team, Rotor engineers worked with the riders and team mechanics to make improvements on a few small details of the oft-overlooked bottom bracket. The aforementioned seals were an improvement, as external bearing bottom brackets of this type have long been known to possess a considerable greater amount of drag compared to some of the benchmark bearing assemblies from earlier generations (think Campagnolo Record square taper). Rotor also thought to improve the plastic caps that snap into the bearings. We often call them dust caps, but they have a structural place in the bottom bracket system, providing a bit of compressive relief in the slip fit between the spindle and the inside diameter of the bearings. But as they also provide a built-in washer between the crankarms and the inner bearing race, too much compression or deformation under load could result in poor bearing preload and lateral misalignment as you pedal. Rotor has eliminated any chance of this and the result is better shifting.The Rotor BB1 Zero Ceramic Road Bottom Bracket has Black anodized CNC machined 7075 alloy cups. They are threaded to fit 68mm English bottom bracket shells. This BB1 Zero bottom bracket will fit all Rotor and Shimano compatible cranks with a 24mm spindle.