I run my modern road bike wheels in my tall bike, 10 speed wheel with a MTB derailleur from 2008 with a suntour thumb shifter from 1988. It shifts just fine IMO, BUT as I have a thumb shifter I can move my shifter a lot more precisely than a downtube shifter...
I don't have good pics of it handy, but here is the left grip, I have a triple on the bike, the bike actually has an %805 gear range LMAO!! Yea, it'll climb STEEP hills, and it goes over 50 MPH on descents just fine.
Some pics from a trip up to "Onion valley" from this past spring, this is according to some the most difficult legal road climb in North America, 5,200' in 12 miles.
