This press-in bottom bracket is specifically designed for older Pivot Cycles aluminum mountain bike frames. The aluminum cups are machined to the perfect tolerance to fit the Pivot BB shells. The bearing-to-cup clearance has also been custom engineered to prevent ovalized BB shell tubes from distorting the bearings--leading to much longer bearing life than the OE bottom brackets provide. The machined aluminum center sleeve is a special narrow design that won't interfere with the extruded supports that protrude inside the Pivot aluminum BB shells.

XD-15 High Nitrogen Steel Alloy is 3.5 times more corrosion resistant than 440C Stainless Steel. In the past, ceramic hybrid bearing manufacturers were faced with a choice in bearing race material: 1) The longer fatigue life of SAE52100 bearing steel when paired with the extremely hard ceramic balls, or 2) The corrosion resistance of 440C stainless steel for use in harsh environments. If they opted for the longer fatigue life of 52100 bearing steel, the intrusion of water would always be a threat to the races. If they opted for 440C Stainless, corrosion would become less of a threat at the expense of longevity. The XD-15 steel not only combines the benefits of both, but EXCEEDS them on both counts. Yes, much greater corrosion resistance than 440C and longer fatigue life than 52100 bearing steel.

XD-15 High Nitrogen Steel Alloy has a 40 percent higher load rating than SAE52100 bearing steel. Ceramic hybrids made with 52100 steel races, while having a longer fatigue life than stainless, were still subject to premature wear when used with ceramic balls. Of course the main claim of ceramic hybrids was less rolling resistance, resulting in greater speed and a more efficient transfer of the rider's output to actual forward momentum. Wouldn't it be great to get this superior rolling quality while actually increasing longevity of the bearing? Now you can. XD-15 has an extremely fine grain structure which