RT2 Megaexo BB size

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09-23-12 | 10:20 PM

CaptainHaddock

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From: PDX!

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RT2 Megaexo BB size

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

09-24-12 | 12:09 AM

veggie

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Bikes: 1973 Schwinn Paramount P10-9, 1988 Cannondale SR2000, 1994 Bridgestone XO-4, 1998 Bianchi Sam Remo, 1998 Ibis Spanky, 2009 Soma Rush, 2012 Surly Crosscheck

09-24-12 | 03:31 AM

Dean V

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Regular English thread BB. 1.37" x 24 tpi. Or do you want some other dimension?

09-24-12 | 09:05 AM

CaptainHaddock

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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!

09-24-12 | 01:11 PM

Dean V

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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.

09-24-12 | 01:20 PM

waynesulak

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Quote:

Originally Posted by Dean V

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.