Help me understand bottom brackets.

[Hepmike]

I'm sure this will sound really dumb, and I'm going to ask anyway.

GXP= SRAM
BB30=Shimano

??

I've got a frame with English threads, and a SRAM Red GXP crankset. So as long as I get the SRAM version of a Chris King BB, I won't need any adapters to work with my cranks, right?

[jtakeda]

Yes, CK Sram THREADED BB cups and you're good.

BB30 is a bottom bracket standard, Not a Shimano BB type though
and
Campy=Ultra Torque

[Hepmike]

Thank you.

[shovelhd]

If I remember right GXP started with Truvativ, which is now an SRAM company. GXP is a threaded BB with a tapered crankshaft. You just need to match threads.

BB30 is a spec that I believe was created by Cannondale. Shimano cranks have never been BB30 compatible out of the box. Shimano has had different specs over the years but the current spec is Hollowtech II, which is a threaded BB with a straight crank shaft.

Others can elaborate.

[ceolwulf]

elaborate.


Certainly is.

http://problemsolversbike.com/files/tech/Bottom_Bracket_Standards_Reference.pdf <~ might help.


Sent from my iPad using Tapatalk

[donevwil]

So as long as I get the SRAM version of a Chris King BB, I won't need any adapters to work with my cranks, right?

Please correct me if I'm wrong, but as I understand it the CK GXP BB is nothing more than the Shimano 24mm axle BB with an included adapter kit. So, yes you do need adapters, but they are provided in the CK GXP BB kit. During crank installation you will need to add the requisite shims and spacers according to CK's instructions. It's not as straightforward as crank installation into a SRAM BB, but everything I've heard is that it works fine.

[Vinci]

Please correct me if I'm wrong, but as I understand it the CK GXP BB is nothing more than the Shimano 24mm axle BB with an included adapter kit. So, yes you do need adapters, but they are provided in the CK GXP BB kit. During crank installation you will need to add the requisite shims and spacers according to CK's instructions. It's not as straightforward as crank installation into a SRAM BB, but everything I've heard is that it works fine.
You are correct.

All the same bearings and cups, just added washers/etc for the GXP adaptation.

With that in mind, if you get a good deal on a Shimano CK bottom bracket, you can buy the GXP gear for it on its own.

[Rob1519]

You are correct.

All the same bearings and cups, just added washers/etc for the GXP adaptation.

With that in mind, if you get a good deal on a Shimano CK bottom bracket, you can buy the GXP gear for it on its own.

I have heard good things about CK BB's but do not like the idea of having to use adapters/washers to install a Shimano designed BB into a GXP application.

After a little more research, I selected a ceramic BB from VCRC for my Red GXP cranks. The VCRC BB has been great and has performed without issue.

[donevwil]

I have heard good things about CK BB's but do not like the idea of having to use adapters/washers to install a Shimano designed BB into a GXP application.

After a little more research, I selected a ceramic BB from VCRC for my Red GXP cranks. The VCRC BB has been great and has performed without issue.

I'm with you Rob, have heard stories about both the CK and Hope "adapted" BB's creaking.

So the VCRC is an adapter/shim-free solution ? I'll have to look into that. I've been eyeing the Enduro BB as well.

[Dead Man]

I'm definitely no expert, but I think the $25 GXP BB is the bees knees. Cheap and durable. The GXP in my commuter did countless thousands of miles through PNW rain and road grime this winter and spring, and is still silent, tight, and smooth. Makes high-end BBs obsolete, to me.

[jds108]

I'm with you Rob, have heard stories about both the CK and Hope "adapted" BB's creaking.

So the VCRC is an adapter/shim-free solution ? I'll have to look into that. I've been eyeing the Enduro BB as well.

I have the same setup as Rob (mine is a Force crank) and no adapters, no extra washers and the bb is smooth as silk. That bike doesn't get used much so I can't comment on longevity but it should be the same as any other.

[shovelhd]

There is no need for a special BB for a GXP crank in a threaded BB shell.

[jds108]

There is no need for a special BB for a GXP crank in a threaded BB shell.

Except for the fact that one side of the axle is 24 mm diameter and the other is 22 mm...

[Hepmike]

It's true...I used a SRAM "team"(?) GXP BB on my Seven for years/ thousands of miles without issue. But the lure of 'blinging' out my Moots has me questioning my utilitarian core in so many ways that are wrong...

[shovelhd]

Except for the fact that one side of the axle is 24 mm diameter and the other is 22 mm...

I understand that. I mentioned that it was tapered. There is no need for BB's with shims and adapters. A standard Apex/Rival/Force stainless or Red Blackbox ceramic will do fine without any shims or adapters.

Capisce? :)

[Hepmike]

FWIW, VCRC has an overstock store on eBay, GXP and BB30 ceramic BB's (new) for $89 shipped. That's significantly less $$ then the (standard!) CK, and a pretty attractive offer IMO.

Consider this a PSA.