The 10-speed drivetrain on my Carbent has not shifted crisply in the rear since the bike was new. It was originally equipped with Dura Ace bar end shifters and Shimano Ultegra road bike front and rear derailleurs. Since I have had such good luck with the 10-speed SRAM Rival drivetrain on my Musashi, I replaced the right shifter with a SRAM TT-500 bar end, the rear derailleur with a SRAM Rival unit, and the Shimano cassette with a SRAM cassette. Still experienced some shifting problems. My latest attempt to improve the situation was to replace the bar end shifters with SRAM X.9 trigger shifters. In conjunction with the shifter change had to replace the Bacchetta long-reach handlebar with a RANS B-41 handlebar for leg clearance. The Ultegra road bike front derailleur was of course not compatible with the SRAM "Exact Shift" trigger shifter (The large lever on the shifter wouldn't even budge the derailler's lever arm). I solved that problem by fabricating a 15 mm extension for the lever arm. Shifts easily, now, and indexes properly. The rear derailleur upshifts fine, but downshifting against the spring pressure is not completely satisfactory, as I sometimes have to actuate the shifter lever again to center the chain on the cogs. My next step will be to replace the large diameter shifting cable with a smaller diameter one (Might be binding). If that doesn't work, may try a SRAM X.0 derailleur. A continuing saga. Oh well, at least I don't have bar ends poking me in the stomach when I make sharp turns.
RANS B-41 handlebar, SRAM X.9 trigger shifters, and foam grips
Comparision of Bachetta long reach handlebar with RANS B-41 handlebar
Completed trigger shifter installation