Varies with every binding, look at the size chart. If you overlap, it's a lot better to be a big foot in a small binding than a small foot in a big binding, assuming it actually fits.
For Cartels with a 7.5, you definitely want the small. For many other bindings it would be a medium. 7.5 is usually around the cusp. But, I have test fit a 7.5 K2 in both a small and medium in cartel, and the Medium was just too big. Fills the small up nicely.
Last edited by jtg; 02-09-2014 at 04:33 PM.