Tandem Cycling - RT2 Megaexo BB size

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CaptainHaddock
09-23-12, 10:20 PM
So I cannot seem to find any kind of white-paper or documentation otherwise on the size of the captain BB for a Cannondale RT2 2012. What say you Tandem crew?

thanks,

James

veggie
09-24-12, 12:09 AM
http://www.shan-precision.com/images/Pic_06.jpg
Dean V
09-24-12, 03:31 AM
Regular English thread BB. 1.37" x 24 tpi. Or do you want some other dimension?

CaptainHaddock
09-24-12, 09:05 AM
That actually cleared up one point of confusion, the other being is the BB 68mm, or 73mm? (if there is somewhere on the external cups I should be looking for this info, I have not seen it)

Thanks!
Dean V
09-24-12, 01:11 PM
68mm. This is the standard width for an English BB. 73mm would be weird. Italian (M36 x 24 tpi x right hand thread both sides) is 70mm.
waynesulak
09-24-12, 01:20 PM
68mm. This is the standard width for an English BB. 73mm would be weird. Italian (M36 x 24 tpi x right hand thread both sides) is 70mm.

The 73mm BB is a mountain bike standard BB width that was adopted by Santana. FSA tandem cranks are made to this standard and use a spacer when installed on a 68mm BB shell. Using an Italian BB on a tandem would put the thread locker and torque to the test with twice the power tending to unscrew one side of the BB.