Angular contact bearings result in 100% ball engagement when
pre-loaded. Chromium steel bearing races are given Cryogenic Treatment after heat treating.
The ball bearings are Grade 5 CERAMIC (Silicon Nitride)
with nylon-graphite retainers. The cartridges are ABEC 5 level precision. The sealed
bearings are packed with an 80% fill of Realube Bearing Compound. For future service, the
bearings are easy to disassemble.
Cup threads are "English/BSA" (1.37 in x 24 TPI) The cup dimensions match Shimano Hollowtech
2 mountain cups. However, because of the special cup spacers included and the telescoping
inner sleeve, this bottom bracket is compatible with road and mountain crank sets.
5 special color-matched aluminum cup spacers are included. The supplied sealed inner sleeve
is machined and anodized aluminum.
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.
bearings in our BB cup sets do not use axle shims,