I.16.1. Material

Most important is the correct combination of materials. The cone ring has to excert friction to block the reaction torque of the planetary system. If you combine an aluminum cone with an aluminum bottom bracket shell, friction is low. Same for steel / steel combination.

An aluminum bottom bracket needs a steel cone ring, and a steel or titanium bottom bracket needs an aluminum cone ring! Only this combination secures the drive from slipping under load.

The photo shows a knurled steel cone ring (black) and an aluminum cone ring with smooth surface. Both are for knurled gear housings.

Please notice: the narrow type of steel cone ring is always slotted to match the bevel of the bottom bracket shell perfectly.

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