Is there any standard formula for matching for the two? Obviously, you need a wider tire on a wider rim, and vice versa.

The reason I ask is I've just bought my first new bike in about twenty two years (a Surly Karate Monkey frame) and am trying to figure out what rims to stick on it... I'm tenatively planning to run 700x32's on it, which should be about equivalent in width to the 1.25 slicks I used to run on my commuter, which is what this bike is replacing.

Thanks in advance.