Lightweight crankset for Emonda, BB90

[FIJIGabe]

They most definitely do. Any dealer should have that in stock.

[Mep]

Trek likely has a BB “kit” for the Sram Gxp crank which will ensure correct spacing, compression, etc. you should just get it. They’re not overly expensive.

Is the BB kit conversion going to add some weight? Just looking at Shimano BB vs SRAM BB weights it looks like Sram is heavier by 40ish grams.

[Calnago]

I don’t know if it would add weight or not, but ya gotta do what ya gotta do. Use the kit whichever way you go.

[Mep]

I don’t know if it would add weight or not, but ya gotta do what ya gotta do. Use the kit whichever way you go.

Fair enough. Just noting that the "lightest" crankset option should be considered as the whole system including the bottom bracket and auxillary parts required.

EDIT: just educated myself a little more on this and it looks like the conversion kit simply replaces the bearings with slightly different dimensions and adds a washer, so the overall weight difference should be rather marginal.

[alcatraz]

Reasons to go gxp bb:
It's the intended bb for that crank.
Usually long lasting components.
No need to play with spacers+wavy washers.
Quicker install.
Potentially less play in the crank.
Longer intervals between change because each bb kit will change bearings and dust covers for maximum protection.

Reasons to go gxp conversion:
Cheaper.
Wider choice of shimano mr24377 bearings available.
NDS bearing isn't special and hard to source.
You can fit a shimano crank if you want.
Few grams lighter.

If you do go the conversion way swapping only bearings you could sooner or later need to get new dust covers which only come in bb kits I think. (Not sure though). I currently have a problem with water ingress on the NDS side bearing no matter if it's new. Something about the dust cover doing the opposite of what it should do.