Trailer Tire Wear Chart

Bias Ply Trailer Tires and Radial Trailer Tires
Proper wheel selection is a very important component of your trailer gear system. When replacing your trailer tires/rims it is critical that the proper size and load range be selected in order to match the load requirements of the trailer. The following characteristics are extremely important and should be thoroughly checked when replacing trailer tires.

TIRE CONSTRUCTION TYPE - Bias Ply vs. Radial

TIRE APPLICATION TYPE - (ST) Special Trailer vs. (P) Passenger Car

TIRE SIZE - % of section height / section width Refereed to as 'Aspect Ratio'

TIRE LOAD RANGE - Load carrying capacity and air pressure rating

RIM SIZE - Diameter and width must match tire

RIM BOLT CIRCLE - Diameter of bolt circle must match hub

Quite often consumers are uncertain how to read or interpret specifications on a 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)

THE METRIC SYSTEM - (ST205 75D 15) currently being phased in by trailer tire manufacturers, indicated the tire application type (ST-special trailer), the section width (205mm), the 'Aspect Ratio' (75), the construction type (D= bias ply), and rim dia.(15")

Proper rim selection is also important to assure replacement wheels will match your existing trailer hardware. Be certain to match your wheel 'bolt circle' pattern to the axle hub. The bolt circle is determined as follows: Tire 'load range', or the maximum weight each tire can safely support, must be considered when selecting the proper size tire for your application. The load range and maximum weight capacity are indicated on the tire side wall.

LOAD RANGE B = OLD 4 PLY RATING

LOAD RANGE C = OLD 6 PLY RATING

LOAD RANGE D = OLD 8 PLY RATING

(pdf)Tire Wear Chart