Snow, sleet, rain, mud, river crossings--you name it, the bearings in this bottom bracket can handle it. XD-15 is the ultimate ceramic bearing for your bicycle hubs when nothing but the fastest AND most durable will do. Silicon Nitride balls are 7 times harder than steel, and the XD-15 uses the very best, made in USA Grade 3 Si3N4 balls. XD-15 nitrogen steel alloy has proven it's superior corrosion resistance and longevity in aerospace applications. It's tough, long lasting, and the THE MOST corrosion resistant race material available.

For 100mm wide bottom bracket shells and Shimano Hollowtech II cranks (or other 24mm spindled cranks designed for 100mm wide BB shells).