Ahead on a carbon frame

[rallycol]

Were the bottom bearing sits in the frame ,is the steel or alloy insert that is directly pressed/bonded in replaceable,also does the bearing directly run on this or is this a sealed item that only rests on it,BTW this is on a Boardman carbon frame thanks Colin

[pdV6]

Don't know about that specific frame, but would have thought it likely that the BB shell would be bonded to the CF and thus non-replaceable.

If the threads are knackered, your LBS might be able to re-cut them, though.

[Nick_F]

I think the OP means the bottom headset bearing, not the BB. I would imagine that the insert is pressed, rather than bonded, into the frame and that the bearings themselves are sealed cartridges so that the insert sees no wear provided it's properly adjusted. There are an awful lot of different designs, though.

Edited by Nick_F on Thursday 8th July 12:41

[rallycol]

Thanks Colin