Prefix Letters used by the Tire and Rim Association in Tire Size Designations and Their Definitions

Posted by Petra on 2/4/2012 to Trailer Tires FAQ
PREFIX LETTERS USED BY THE TIRE AND RIM ASSOCIATION
IN TIRE SIZE DESIGNATIONS AND THEIR DEFINITIONS

Prefix letters are included, when necessary, as part of Tire Size Designations to differentiate between tires designed for service conditions which
may require different loads and inflations and/or tires designed for, and which must be used on, different types of rims.