Is Mega Exo BB same as GXP?
Weeman1973
Posts: 471
I have a Kuota frame set with s BB386 & looking to change chainset.
I'm looking at an FSA SLK which comes with Mega Exo BB.
I know I can buy adapter cups to allow my BB to accept GXP style cranks but it doesn't say anything about Mega Exo?
I believe the issue might be in spindle length as they need to be 86mm to fit the BB386 but I'm thinking if Mega Exo & GXP are the same, surely the adapter cups to change my BB386 to GXP will work for Mega Exo too?
I'm looking at an FSA SLK which comes with Mega Exo BB.
I know I can buy adapter cups to allow my BB to accept GXP style cranks but it doesn't say anything about Mega Exo?
I believe the issue might be in spindle length as they need to be 86mm to fit the BB386 but I'm thinking if Mega Exo & GXP are the same, surely the adapter cups to change my BB386 to GXP will work for Mega Exo too?
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No, Gxp has a stepped spindle, so one side is 24mm but the other is 22. Megaexo is the same as Hollowtech 2 so you should be able to find an adaptor.
Really good article here:
http://www.bikeradar.com/gear/article/c ... ets-36660/0 -
super_davo wrote:No, Gxp has a stepped spindle, so one side is 24mm but the other is 22. Megaexo is the same as Hollowtech 2 so you should be able to find an adaptor.
Really good article here:
http://www.bikeradar.com/gear/article/c ... ets-36660/
Thanks for that. I already use a Dura Ace chainset so have adapters in place for that. You think those adapters I use for the Hollowtech II DA cranks will also be suitable for the FSA cranks with Mega Exo BB?0 -
FSA cranks with a 24mm spindle will fit hollowtec 2 bottom brackets but in my experience they are a tighter fit and they do not slide together as Shimano cranks do. They will need a good clout with a rubber hammer to assemble them.0
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Depends on your adapters, really.
If it's an adapter that lets you thread in a regular BSA bb, then you can fit a MegaExo BB. If it's an adapter based on bushings/spacers that fit into 30mm ID bearings then it won't work.
There's actually three road MegaExo variants about. The mid-range (Gossamer, Energy) is 24mm id, and the same as Shimano. The low end (Omega) is 19mm and compatible with nothing. As far as I remember, the top end (Energy 130mm BCD, SlK and K Force are different again, though I'm buggered if I remember how.0 -
Wow - they really make it easy don't they!
Looks like the easiest thing will be to either buy a BB386 specific Chainset (mega bucks, even for the cheapo FSA Gossamer style!) or get another Hollowtech II chainset that I know works with the adapters I am currently using.0 -
Sorry, to clarify. If your adapter is a spacer/sleeve design that the crank slots straight into, then you'll be able to fit the FSA crank in the same way. The high end FSA cranks don't use pinch bolts a la Shimano, but a wave washer and a single axial crank bolt. This is the reason for the other variant of megaexo BB. It'll work, but I think the different fitting for the NDS crank can cause issues down the line.0
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MisterMuncher wrote:Sorry, to clarify. If your adapter is a spacer/sleeve design that the crank slots straight into, then you'll be able to fit the FSA crank in the same way. The high end FSA cranks don't use pinch bolts a la Shimano, but a wave washer and a single axial crank bolt. This is the reason for the other variant of megaexo BB. It'll work, but I think the different fitting for the NDS crank can cause issues down the line.
Yep, its he bush / sleeve style adapters I use to convert my BB386 bearings (30mm) into Hollowtech II compatible 924mm) rather than screw types.
Also looking at a high-end FSA crank like SLK or K Lights o these will come with the washer / crank bolt you mention so I think it's regular Hollowtech II cranks just because I know they work with my set up.
Difficulty is finding a 50/34 chainset with 170 cranks in a high end (Dura Ace) Hollowtech II to fit 10 speed which is why I was looking at the FSA in the first place.0
