>>1211904I did it for thousand miles. My 700c frame cannot physically take a FD, there's no cable stop for it and the down tube is the flat large kind, that means no adapters. It's okay because I didn't really want to install another FD anyway, I do want to upgrade to 9v. New rim, new RD, new shifter etc. I never tried it before.
>>1211906The biggest one should go with the lowest 3-4 gears at most. The middle one goes at least with the lowest 5, possibly all of them depending on how smooth it's adjusted. The lowest one goes with the 3-4 biggest gears in the back.
And again it entirely depends on the size of the crankset. 48-38-28 and 14-28 7 speeds? It will take months to use 48-14 with ease. 42-32-24? You'll overspin 42-14 in no time.