Shimano Shifting Question
 

Not so much of a Shimano guy, and I have a question about Shimano shifting levers. Do Shimano dual control indexed handlebar levers handle both double and triple cranksets or are there 2 ring and 3 ring specific models? I would be interested in knowing about Dura Ace, Ultegra, and 105 only and I am interested in 8 speed or 9 speed levers. Thank you very much.

Most are specific, 2 or 3, but some models do both. Best to include gearing, 8 9 10 +...

I have successfully used triple-specific left STI levers to operate normal double arrangements. The trick was to set it up using the shifter's 1st and 2nd detents, with the 3rd detent locked out against the hi-limit screw.

Also, there won't be fully-functioning trim positions at the big-ring position, but which can be adjusted around with fine-tuning (and/or by very slightly widening the cage width near the front of the cage). Done this many times actually.