dogg_man

I got this bike in January of last year. Wow its been a year...
https://www.specialized.com/us/en/bc/...011&spid=52848

I think its a beautiful bike and rides like a dream, however I want to upgrade the crankset to a SRAM Force but don't know if I can since the current crankset the bike has is a SRAM S100 with a powerspline BB.

My LBS just shrugs when I ask them and want me to take it in so they can "inspect" my bike and figure out what kind of BB I would need. For a nominal charge of course.

I've emailed specialized, posted on specialized twitter page etc etc and no response yet.
Figured I'd toss this out there on these forums and hope for the best.

I'd like to go GXP since I can get a good deal on a ceramic BB but who knows.

Any input is appreciated.

Thanks!

fr333zin

Yes, you can upgrade to SRAM Force crankset, as you plan to remove the Powerspline BB to replace with GXP. The difference is that the Powerspline BB has internal bearing cups and contains the axle, whilst GXP has external bearings and the axle is permanently fixed to the drive side crank. It is a fair bet that your Specialized Allez has an English threaded bottom bracket and the bracket shell will be 68mm, the 73mm ones are for MTBs. Hold on to your chainrings, though, because I read they are SRAM Red and can't have much wear on them yet. Incidentally SRAM Force uses the same carbon crank arms as Red.

I built a new bike last year using Force + GXP, I recall the BB came as part of the crankset but checking around shows this is not always the case. I had planned to use a Hope BB and there would have been a shim needed to match the SRAM axle. However a 73mm BB arrived and got sent back, so I built with the SRAM BB and this is still smooth after 2600 miles and no attention. If you can get ceramic then go for it, just check the need for shims. I am just building another bike with a ceramic BB + RotoR cranks and the difference is definitely noticeable on the stand but haven't got to the road yet.

If you thought about doing the installation yourself, there is some investment in tools needed. Here's how to remove the old Powerspline BB: https://www.parktool.com/blog/repair-...et-service-bbt

Here's how to fit the GXP BB (Giga X Pipe): https://www.parktool.com/blog/repair-...o-ultra-torque

fr333zin

Forget my point about shims unless Hope is your chosen BB.

dogg_man

Thank you so much for your reply. I figured you could go from Powerspline to GXP but not 100% on it.

Thanks again.