First of all, yes, Gates is coming out with a 66T CenterTrack tandem (8 mm pitch) sprocket in June of this year. Second, it's not necessarily just for Calfee and Cannondale, as we
could get them, too, if we wanted. Which brings me to my third point, that being I don't think we'll want to design a new frame just for an additional 12 mm (1/2") of boom tube length, so 29" instead of 28.5" (approx.). That's right: the 66T sprockets only increase the boom tube length by one half of an inch; not worth the effort, IMO.
It's likely that the 66T sprockets are in response to a particular OEM application where they have enough volume to justify tooling up another (at this point unique) size sprocket. C'dale is the likely suspect, IMO. But why would they bother with 29" boom tube instead of the informal tandem standard (for belt drive, anyway) of 28.5"?
Originally Posted by
TandemGeek
Doh! I forgot the tandem CarbonDrive / sync drive system and the regular Gates CarbonDrive / drive-side systems use belts and sprockets that have a different pitch: 8mm for the tandem application and 11mm for the drive-side.
However, timing is everything -- no pun intended -- and it turns out Gates was already working to bring a 66t sprocket system to market this summer for Calfee & Cannondale that will work with a 30" boom tube dimension. So, I'll have to cool my jets until June when they become available via Gates or Calfee.