I have a Shimano 105 chainring on a Schwinn Tempo bike from the early 80's. It is a 52/42 biopace and I would like to replace it with another compact but with a 34 tooth small chainring (for easierIMG_1756.jpgIMG_1757.jpg climbing). I see them on ebay quite often and plan to buy one when I get a decent deal, but I wanted to be sure of compatibility. As long as it is a compact will it work with no modifications of my rear cluster? And my bonus question is --Can I put a triple chainring on the bike with little trouble? Any suggestions would be greatly appreciated.