Originally Posted by BeantownFixed
I stopped before I got to rake because although I understand the concept I'm no expert at suggesting what rake is appropriate etc. Is the axle-crown length just what determines what size wheels you can run?
A-C length can determine what wheels you can run (which also affects handling), but it is determined by a lot of things. Here's a couple examples:
Think of a blinged out NJS track fork. Super-low clearance, the top of the tire clears the bottom of the fork by about 2mm, and the fork crown is about 10mm thick. This makes the A-C length an estimated 325mm.
Now think of a cyclocross fork. Built for the same size of wheels, but the tires are way bigger, and there is a lot more clearance between the top of the tire and the fork. Also, the crown is thicker. You might have an A-C length of 360-380mm (completely pulling numbers out of my ass).
You put a CX fork on your NJS bike, and the bigger A-C length will pick up your front end, which will slacken the crap out of your head and seat tube angles. Depending on the rake of the fork, it will also drastically affect the trail. If you're going to replace a fork, if you can match the rake and the A-C length, you should be golden.