Replacement BB - Bontrager Cranks

ian.twin

Looking for some help and advie wrt Bottom Brackets.

I am stripping my damaged Trek TCT500 of components to install on an egerly awaited (new) Ribble frame.

The question I have is will any replacement BB (assuming the thread etc are correct) fit the old crank to the new frame?

Thanks in advance for any help

John.T

The one from the Trek should fit fine. If getting a new one get a 68mm English one with the same length axle.

ian.twin

unfortunately I broke the plastic tube which goes between the two threaded cups and holds the "O" rings, so I'll need to get a new one. When you say get the same axel length are you refering to the said plastic tube which I broke?

John.T

I was guessing you had a square taper BB. Not the tube. You may be able to get another from a good LBS old bits bin or run without it until the BB needs replacing.
It will probably be a HT2 (Shimano) type but you need to check. See if the axle will fit through both BB bearings from either side. IE both bearings have the same inside diameter. If so it is HT2 so any road one will fit. If the non drive side is a little smaller then you need to check further. Trek or SRAM giga X pipe.

ian.twin

Thanks for your input. I appologise for my stupidity but I've never taken a BB appart before.

The plastic tube does say GXP on it. Is this the make, model or something?

Also, the axel had an aluminium boss on the non drive side to locate the bearing. It was this that stopped me from pushing the axel through the plastic tube (and indeed lead to its dimise.

John.T

GXP is Giga X Pipe. A SRAM / Truvatiz format. Also some FSA.
http://www.parktool.com/blog/repair-help/external-bearing-crank-systems-hollow-tech-ii-megaexo-gigaxpipe-x-type-ultra-torque-bbt
Descriptions of most external BB systems here. Scroll down to SRAM for yours.

ian.twin

Thanks alot John.T

Pokerface

Bontrager uses the GXP bottom brackets (not Shimano). You can pick one up for about £20.

Good luck.

ian.twin

Thanks poker face