The tire size is written on the tire s sidewall. LT truck tires are designed for heavier loads and more rugged service conditions. Width of the tire, in millimeters. The height of the sidewall section compared to the width of the tire.
Short sidewalls deliver crisp handling.
Tall sidewalls give a smoother ride. For a specific tire width, the smaller this number, the shorter the sidewall. Construction R indicates radial construction. This indicates the distance across the doughnut hole of a tire, in simple terms. You must match wheel diameter and tire diameter.