Bottom Bracket Confusion

[Sbloomer]

Hi all

 

As part of a new build (Bianchi Kuma Frame) I bought a used SRAM Carbon Crank and matching GXP Bottom bracket.  I was under the impression that the threads in the frame were standard.

 

Now, the BB doesn't fit.

 

The drive side of the BB fits the non-drive side on the frame, but the non drive side of the BB doesn't fit the frame at all.  In fact the threads of the non-drive side seem to be in the opposite direction of the threads in the frame.

 

So my question is, what BB will fit other than the tapered axle BB i got it with the frame.  I don't really want cranks that use this BB.

 

 

 

[Wannabe]

Some frames has got the Italian thread BB cups, others has the English thread cups.

Try and establish which BB you have there (should be printed on it somewhere) and then change it for the other standard. The one turns clockwise, the other anti clockwise.

Seeing that you have an Italian bike, I would bet my bottom dollar that you will need an Italian thread BB, which turns to the right hand side on both ends.

 

Google is your friend to get more info on it, or take it to your friendly LBS to help you out.

 

Here is a good read to help you in the right direction:

https://www.sheldonbrown.com/cribsheet-bottombrackets.html

Edited May 23, 2019 by Wannabe

[Captain Fastbastard Mayhem]

YOur Bianchi probably has an Italian threaded BB shell, and that's an English threaded BB, most likely. 

[Martin PJ]

https://www.buycycle.co.za/products-en-7/sram-bottom-bracket-gxp-italian-thread/

 

Check this out, if your frame is Italian, this would work.

[Longbarn Killer]

I would've thought the same about Italian vs English, but I find it interesting that the drive side does fit the non-drive side.

[Martin PJ]

I would've thought the same about Italian vs English, but I find it interesting that the drive side does fit the non-drive side.

 

That is Italian, both sides threaded the same way.

[Wannabe]

On Italian, both threads in clockwise, so the one side should fit, irrespective.

[Martin PJ]

You could find someone with old GXP bottom bracket, if the drive side is not too bad, then use that on the non drive side.

[DieselnDust]

Italian threaded BB's have right hand threads on both drive and non drive side. Thats why the one side does not your BSA threaded bb

[droo]

You could find someone with old GXP bottom bracket, if the drive side is not too bad, then use that on the non drive side.

 

This won't work for 2 reasons - 1, the threads are a different OD and pitch, and 2 LHS and RHS GXP bearings are different sizes.

[Martin PJ]

This won't work for 2 reasons - 1, the threads are a different OD and pitch, and 2 LHS and RHS GXP bearings are different sizes.

Yes, good point about the bearing size, I remember now the GXP shaft is 22 mm on one side and 24 mm on the drive side.

[DieselnDust]

Yes, good point about the bearing size, I remember now the GXP shaft is 22 mm on one side and 24 mm on the drive side.

 

 

no the thread is also different 36mm x24tpi

BSA 1.370x24tpi or 1.375x24tpi

[Martin PJ]

no the thread is also different 36mm x24tpi

BSA 1.370x24tpi or 1.375x24tpi

You can see this in the picture posted of the crank. I didn't comment on the thread.