Originally Posted by
nfmisso
Grip shifters are designed to fit on bars that are 22.2mm OD; most drop bars are 25.4mm or 26mm OD - thus they will not fit.
The easiest solution is bar end shifters, which are available in both friction and index. For example:
https://www.amazon.com/MicroShift-Do...ifters+9+speed
There are solutions keeping the grip shifters, but they are heavier, more complicated and require custom fabrication.
22.2 is the lever, grip area dimension of flat bars, 25.4 or 26mm is the diameter of the clamp area. Most road bars have a diameter of 23.8mm (15/16") outside the clamping area.