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What does the information on the side walls of a trailer tire mean? Quite often consumers are uncertain how to read or interpret specifications on a trailer tire side wall. This problem is compounded by the Trailer Tire Industry's use of three different size identification systems on trailer tires. The following are examples and explanations of tire code.

THE NUMERIC SYSTEM - (4.80 X 8) mostly used on smaller trailer tires, indicates the tire section width (4.80"), and the rim diameter (8")

THE ALPHA NUMERIC SYSTEM - (B78 X 13 C) common on 13"-15" trailer tires, indicates air chamber size (B), the 'Aspect Ratio' (78), the rim diameter (13"), and the load range (C) These tires have a matching tire available in the METRIC SYSTEM.

THE METRIC SYSTEM - (ST225/75D 15) currently being phased in by trailer tire manufacturers, indicated the tire application type (ST-special trailer), the section width (225mm), the 'Aspect Ratio' (75) (only important to tire engineers), the construction type (D= bias ply, R= Radial ), and rim dia.(15").

LOAD RANGE- The load range of a tire is indicated by a letter, A through E, and is stamped on the sidewall of the tire. Tire charts, available from any tire dealer, have these letters in parentheses after some of the tire load limits. The letters are placed next to the maximum weight for that load range.