As you can see from my sig., I have a 1991 Miyata that runs ultegra 600 tranny, all around. At the time, ultegra = 7 speeds at the back. The crank is 53-42, and although I already have a relatively large cassette (13-28), I'm just rather unfit and would prefer something closer to compact gearing.
My question is this. If I simply change the crank to a 50-36 compact, claimed to fit for 9 and 10 speeds only, will I have issues running the 7 speeds in the back? Will the chain be too loose for the crank's teeth?