UKC

Hi,

So, it seems I need a new BB on the mountain bike. Current one is Shimano SM BB70 - it's an old XT chainset.

That BB seems to have been discontinued and I'm trying to figure out an equivalent replacement - I know that there are also FSA and RaceFace ones that share the same BB, so any pointers welcomed (actually replaced the RaceFace on on my sister's bike with a Shimano one, but it was a good few years ago and I can't remember the specs).

Thanks in advance.

Any shimano Hollowtech II BB will be fine

e.g. https://www.bike-components.de/en/Shimano/Deore-BB-MT501-Hollowtech-II-Bott...

or 

https://www.chainreactioncycles.com/p/shimano-xtr-bb93-hollowtech-ii-bottom...

yep as above, just be sure to fit any spacers the same as the old

Thanks, that's as I suspected.

Rummaging in the spares drawer in the garage, I found a BB51 that I must have upgraded from at some point, as that seems to be ok - at least, better than the current BB70 - so I'll put that in for now.

Also found another BB70 - interestingly, it seems that in both thoses cases, it's the non-drive side bearing that's gone. Looking on YouTube (there's always a YT video!), it's possible to remove and replace the bearings, so I'll start by getting a new set of 6805 bearings and go from there.

Otherwise, that XTR one you linked might be a nice option, thanks.