Mega Exo BB compatibility

Hi all,

About to pull the trigger on an used FSA Gravity crankset, which comes with a 73mm Mega Exo BB. I need to switch to 68mm. I read conflicting info on compatibility between this and Shimano Hollowtech II.

I don’t really want to spend 50 bucks on a BB for a 40 buck crankset because I am cheap.

So can I go with a Hollowtech BB?


I have fitted FSA gossamer and energy cranks to shimano hollowtech II BBs with no problems. Whilst megaexo is supposed to be the same dimensions, I think there is a minor difference that can prevent the shimano BB from working properly on SLK megaaxo cranks.

How that relates to a gravity crankset ¯_(ツ)_/¯

You could probably add some spacers to fit your 68mm shell with the included BB, but FSA BBs are junk and won’t last long.

You then might be able to get a shimano MTB BB and install it with the included spacers for a 68mm shell. But buying the cranks and not knowing is a risk that might not be worth it.

(ignore the arrow)

I think I should put you on a retainer, given all of the info you share with me regularly. Something tells me that it might be easier to go with a full shimano setup rather than screwing around and probably making a mistake :slight_smile:

Sounds like a better idea.

Why did you want the cranks?

36T new-ish zees with BB:
[edit: $117 at CRC, minus $10 for newsletter signup, so new/warrantied and cheaper.]

(I’ll setup a Patreon.)

It’s all massive overkill for my ancient Apollo! But I am doing it for fun. A guy in Canberra is selling the following for 100:

“For sale is a small MTB group. Including XT RD, SLX crank, shifters, FD. a stem and flat bar.”

I currently have a CRC voucher though…

private group. sounds good though at that price. generally an xt shifter with a lower mech is better than an xt mech with a lower shifter, but you can’t argue for $100!

Noted, let’s see what the guy says. Meanwhile, it’s all for this bike. Not because it’s a good bike, but because I can. The paint is super rough, but I have had it for 20 years.

The plan is to go 1 x 7 (or maybe 1 x 10…). Got newer wheels, Tektro cantis at the ready, riser bars coming etc. Just for fun :slight_smile: