Hey guys,
I was having some issues with auto shifting today on the trail, I got home looked the bike over and noticed some play in my cranks. I took the bottom bracket out to clean and re-torque everything back down and noticed the BB is a 73mm when the bike shell is 68mm. It's an 02 Specialized Rockhopper that I bought used a few weeks back and it's becoming more and more apparent that the previous owner cobbled the bike together to sell it, he did put some nice parts on it like Deore XT shifters and the FSA Cranks/BB but nothing was properly installed/adjusted.

My question is I've read places that you can use a 73mm BB in a 68mm shell but need a spacer, read other places that this won't work. The spindle is the correct length so I don't see why it wouldn't if I threw a 2.5mm spacer on the drive side. I'd rather not buy a new BB so would this work?

It's an FSA ISIS BB by the way.

Thanks

If I understand the problem, you've got a cartridge-type BB on which the position of the bearing cups is fixed relative to the spindle. So for the spindle to be in the correct position, the bearing cups have to be unscrewed from the BB shell by 2.5mm each. If this is your case, then I think Hope make suitable spacers to fit between the cups and the shell. See
https://www.hopetech.com/webtop/modul...structions.pdf
and
https://www.chainreactioncycles.com/M...?ModelID=36416

Yes it is a cartridge, and yes I need to move the drive side out 2.5mm. That spacer looks like it should work so I just need to locate some locally. I'm hoping I won't need to buy a new BB. Thanks