What Our Gearhead(R) Experts Are Saying:"The wide rim changes how the tire behaves on rough roads. It holds lower pressure without the squirm you'd expect, and gives you enough grip in corners to stay off the brakes when the surface gets loose."The 54mm rim depth is deeper than you'd expect on a gravel wheel, and that's the point. Zipp shaped it to create a tight transition with compatible gravel tires, which closes the gap that normally costs you aero efficiency at gravel speeds. The tradeoff is that the 303 XPLR S is only compatible with approved tires, specifically the Goodyear XPLR Slick and Goodyear XPLR Inter, because the system only works when the tire and rim are matched for it.