CeramicSpeed claims that its external BSA bottom bracket (BB) could save as much as six to nine watts of power. Ceramic bearings are harder and rounder than regular stainless steel bearings, so they offer lower rolling resistance, hence better power transfer.
We’ve been running this BB for around 18 months. The performance is impressive - you can feel that the cranks spin much smoother than with a BB with steel bearings, and they’re as good now as they were when first fitted.
Off the bike, give the cranks a reverse spin and it’s amazing how many more rotations they fly around.
The bearings sit in external aluminium cups, made by Rotor, to fit a 24mm crank axle. For the ‘coated’ option (£306 / US$499), bearings are coated in a specifically formulated off-road grease to extend longevity at a small rolling resistance cost, although the cost to you is substantial!
CeramicSpeed makes bottom brackets in various sizes, including BB30 and PF4624.
This article was originally published in What Mountain Bike magazine, available on Apple Newsstand and Zinio.
via BikeRadar.com http://ift.tt/1kSXqFl
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