This press-in bottom bracket is specifically designed for original aluminum Pivot Cycles. These frames had internal BB protrusion that blocked conventional BB sleeves. In addition, the press fits were unusually tight, sometimes over-compressing the bearings. Our 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.

Angular contact bearings are a step forward in outboard bottom bracket design. Why? Deep groove radial ball bearing cartridges are not designed to be "adjusted." Any inward or outward pressure on the inner races put them out of alignment with the outer races, forcing the balls to ride up the side of the groove and exerting greater pressure on the races. This results in increased friction and premature wear. Since almost all outboad crank sets exert some inward pressure on the bearings when installed, it only makes sense to use a bearing designed specifically for such loads. Angular contact bearings also result in 100% ball engagement when pre-loaded, making them stronger and longer-wearing.

ENDURO ANGULAR CONTACT ABEC 5 STEEL BEARINGS

What Does ABEC 5 Mean? ABEC 5 is a standard which requires each bearing to pass many tests in order to meet the scheduled requirements. This includes noise testing at high RPM, extremely tight tolerances for the internal diameter, outer diameter, roundness of ball, trueness of races, and surface finish of all of the above. This is a much higher standard than ABEC 3, even though only differing by 2 digits in rating.

THE BALLS are made from chromium steel. These high precision Grade 5 balls are 5/1,000,000” from exactly round in sphericity. For comparison, Shimano and Campagnolo use grade 25 balls in their top-level components. When talking ball grade, the smaller