[autobon7]

I have what I believe to be a 97 sv 500. How does one know what frame size it is? 3 sets of #'s/letters on frame, assuming ending with m = medium. It reads 1B B1-0302 07728, 223574, 7XCA5WM.

 

[Baker921]

This site will tell you all you need to know http://vintagecannondale.com/info.html
Assuming your characters start IB your frame is Feb '97. As you'll see from the link the rest is no use to you.
Look around the site and you'll find the '97 catalogue. Download this. I think it has the geometry in there which you can compare with the actual measurements from your bike.
Enjoy.