【How-to】Are 700 and 700c the same

It doesn’t mean anything, really. It’s a historical relic. At one point in time, “700c” was a standard tire/rim size, where “c” indicated the bead seat diameter and “700” was the diameter, in millimeters, when the tire was installed and inflated. That “700c” tire size has a 622 millimeter bead seat diameter.