I've got a '89 Schwinn World Sport that was originally 6 x 2 but I've got a 7-sp road triple crankset from the same period that I'd like to put on it (I'm basically trying to build bikes out of all the part that I've got lying around). My clearances seem OK but the original SunTour FD is past it's prime and I don't know if it will handle the triple. I looked online and a 7-sp FD that will handle a triple with a 53T big ring has been elusive. The current FD is a bottom pull, high clamp, with a 28.? clamp diameter as is typical of the Schwinns of that era.

Any suggestions for a replacement? As the R-side Microshifter is friction, could I use a 9-sp FD and just trim with the shifter to accommodate the narrower cage or am I going to be constantly fighting chain rub any time my chainline isn't straight? I'm trying to keep the cost of the FD <$25 if possible as this is a Frankenbike project in hopes of ending up with a comfortable and fun, beater/trainer/Plan B/guest bike without a lot of worries about performance, other than that everything works smoothly.

I've already got a 7sp long cage RD and if my calculations are correct, I should be fine there. Should I anticipate any other problems mixing old 6sp and slightly newer 7sp components? Any other problems I haven't mentioned?