Join Date: Jun 2008
Location: Salt Lake City
Bikes: 2008 Co-Motion Speedster CP
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We have a new Co-Motion Speedster with a similar setup. After reading about all the problems with the 10 speed wide range setups with IRD cassettes and the like, I worked with Bryon at Crank 2 to come up with a 9 speed drivetrain for our new bike when we ordered it last fall. We stuck with the stock FSA crankset and Ultegra FD, swapped out the rear cluster and derailleur for a 12-34 XTR and DaVinci modified SRAM X9. Original chain Bryon installed was a SRAM. Brifters are 10 spd Campy Chorus.
Since we got bike late last fall, we have a little over 400 miles on the setup. I initially had some shifting issues that I believe were related to the chain being a bit short, since Bryon was trying to accommodate both the 12-34 XTR and a SRAM 11-28 cluster using the same chain (I ordered the bike with two wheelsets). It almost worked, but I installed an additional link for the larger cluster and found better shifting. However, it still wasn't clean across the whole range until I changed out the SRAM chain for a Dura Ace 9 speed chain. That made a big difference in both shifting and noise. We are pretty happy with the setup now, except for the occasional phantom shift when standing hard on the pedals on steep hills in the 34 tooth cog and the middle chainring. Still dialing it in, so getting the limit screw set just right might fix that I hope.
I like the simplicity of this setup and overall I think you will be happy with the rear derailleur.