quick one for the hive mind, fsa mega exo B.B. is dead on the road bike, Can I bung any old HT II B.B. on there? FSA marching cranks but look exactly like Shimano ones. Just don’t fancy the £35 fsa B.B.

IIRC the answer is somewhere between “it depends” and “no”.

Some FSA cranks are like the new SRAM ones, there’s a 0.1mm or something difference between them, so the reality is they might work, or they might be a creaky mess.

Also Shimano BB’s use angular contact bearings and pre-load, pretty much everyone else (apart from SRAM who do something different again) including FSA use some variation on washers, springs and elastomers to stop the axle floating around without actually pre-loading the BB and use standard cartridge bearings..

So yes you can use a HT2 BB, but it might creak and it might not last as long as it does in a Shimano setup.

And having said all that, my FSA BB on the road bike has lasted donkeys years (although it rarely gets wet), so I’d happily pay the extra for the correct BB.

I have the mountain bike version of the fsa mega exo and use a XT bottom bracket.

Yes it is a tight fit, a swift bash with a rubber mallet works as the spindle is slightly greater than 24mm. Grease helps with the persuasion.

You have to be careful with the spacer washers to take in to account for the wavy washer. It’s been on for 4 months, has been used in the slop at the end winter/early spring. No issues with it as yet.