T47-Asymmetrical, Thread-In, XD15 Ceramic-Hybrid, Angular-Contact Bearing Bottom Bracket An Enduro Bearings exclusive, our XD15 Pro BBs feature XD15 15 degree Angular Contact cartridge bearings pressed into precision machined aluminum T47 cups that simply thread directly into the BB shell. Utilizing the same XD15 steel as our XD15 Corsa bearing, Enduro XD15 Pro bearings offer a 15 degree angular contact sealed bearing in a standard-sized cartridge. XD15 Pro bearings feature deep-groove raceways allowing for maximum sized Grade 3 Silicon Nitride ceramic balls for for increased contact area and improved performance and longevity. Enduro XD15 bottom brackets are manufactured to the highest standards at the Enduro Bearings production facility in California, USA. Enduro XD15 bearings combine corrosion-proof, cryogenically treated nitrogen steel races with Silicon Nitride Grade 3 ceramic balls in a proprietary process that results in the ultimate high performance bearing setup. Find out why Bike Radar reported the XD-15 Hands down, the best bottom bracket we have ever tested. We are so confident in the performance of XD-15 Ceramic-Hybrid bearings, that we offer a full lifetime warranty against wear and corrosion. The most impressive feature of these bearings is, unlike other bearings, they only get better with use. As the bearings wear-in, the balls actually make the races even smoother. So when compared to other ceramic-hybrid bearings on the market that claim speed and power advantages on day one, Enduro XD-15 bearings not only provide the same initial advantages on day one, but will get even faster and smoother with time and use, while the other ceramic-hybrid options will only get slower. The T47A (Asymmetrical) specification is a new thread-in standard that has is similar in concept to BBRight (but with threads) that been used by a couple brands, including Cervelo and Factor. Shell Fitment: T47 Asymetrical Bearings: XD15 Pro Seal Type: LLB Grease Kluber CRC Marine Grease Axle Size: 24mm, 29mm (DUB), 30mm Warranty: Lifetime Enduro Reference Number: 24mm - BKC-0750 / 29mm (DUB) - BKC-0751, 30mm - BKC-0752