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Reading a Tire Sidewall

Follow the diagram below for a complete overview on how to decipher the information displayed on a tire sidewall to get an idea of what size and type of tires you want.

Use this Tire Calculator to figure out the actual height and width of your metric tires.

Reading a Tire Sidewall
31 x 10.50 R 15 LT C 109 Q
Nominal Overall Diameter (inches)   Nominal Section Width (inches) Construction Code (Radial) Rim Diameter Light Truck Tire Load Range Load Index Speed Symbol
Speed Symbol Speed Category
N 87 mph (140km/h)
P 93 mph (150km/h)
Q 99 mph (160km/h)
R 106 mph (170km/h)
S 112 mph (180km/h)
T 118 mph (190km/h)
H 130 mph (210km/h)
Load Range Ply Rating
A 2
B 4
C 6
D 8
E 10
F 12
G 14
H 16
J 18
L 20
M 22
N 24

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