Educate me about Bottom Brackets.

Thinking about a new crankset, I’ve been using a Shimano HTII for a few years, but looking around at new cranksets there seems to be a few new “standards” around.

Namely GXP and BB30 seem to figure strongly.

So, does the frame need to be prepared in any special way to use these or is it simply a case of removing the old cranks and BB and sticking the new ones in.

Are there any advantages/disadvantage of any of these systems or should I stick with the big S?

Cheers.

Don’t the new std like BB30 (BB90) require a different type of BB shell to the std threaded type, so unless you changing frame to one with this type of BB, you can’t use em.

http://www.bb30standard.com/

BB30 and BB90 Bottom Brackets

You can use GXP, though you’d need to use a GXP BB and crankset and replace the BB with GXP compatible ones (limited selection) when it need replacing.
Why change from the shimano one, what wrong with it, would simply be my questions?

z1ppy speaketh the truth. Stick with Shimano.

gxp is the sram version on shimano gxpII – ime it’s not as good as shimano.

bb30 requires a bb30 frame.

Nowt wrong with the shimano one, just having a look around. I have a spare frame I might build up, so was wondering about putting the old shimano one on the spare frame and something shiny and new on number one bike.

something shiny and new[/url] you say?

GXP – SRAMs version of the Shimano standard, different axle diameter, so not cross-compatible without adapters.

BB30 – bearings that press directly into the frame, think a headset sideways. 30mm ID that accepts a 30mm crank axle.

BB86/90/92/95 – various different standards that involve pressing bearings (either in cups, or as is) into the frame, but still work with ‘standard’ chainsets.

Shimano don’t do BB30. SRAM do GXP and BB30.

at least it’s not a stupid headset question…

Does a bottom bracket come with frame spacers…? 😈