The shape of the tire’s profile (also known as the mold cavity shape) is very important. It affects many factors in a tire’s performance, including treadwear, handling, rolling resistance, and even noise. The basic dimensions of the profile are dependent on the tire’s designated size and are within a standard design “window”. But there are slight changes that can made to the different parts of the profile that can significantly affect tire performance.
Tread Arc (or Tread Design) Width – this is the dimension of the tread face of the tire, effectively measured from the midpoint of each tread shoulder. This is often specified to equal a set percentage of the tire’s section width.
Non-skid Depth (Tread Depth) – the amount of tread depth varies by tire type, with standard passenger tires having less than off-road light truck tires, for example.
Tread Arc (or Radius) – the outer surface of the tread profile is made up of circular arcs or radii that can be flatter or rounder, depending on the type of the tire and its intended performance. Near the center of the tread, the radii are typically very flat, while in the shoulder they are much smaller diameters (and more round).
Curing Rim (or Molded Base) Width – this is the width at the inner diameter of the tire. It’s designed to allow the tire to mount easily on the rim but fit securely on the range of rim widths designated for that tire size.
Rim Guard – this is a thicker section of rubber molded into the lower sidewall area of the tire designed to help protect the edge of the rim from scrapes.