Originally Posted by
headwind15
Because of the hard plastic sleeve inside a grip shifter, the may not even go around the bends of a butterfly handlebar in the attempted installation. Since I was a bicycle store owner for over twelve years, I have a boxes of grip shifters and (Shimano) Rapid Fire shifters. I used to have a big bag of (top mount type) thumb shift levers, but went missing about 6 months ago.
Shifters and brake levers don't go around the bends on a butterfly (trekking) bar. They just slide onto the flat part from the inside. These are Shimano EF-51 shifter/brake levers. I found I did not like this setup as much as I thought I would.