Tire Identification Markings

Format:

Code:

P = Passenger

LT = Light truck

T = Temporary

LTP = Light truck, personal use

Width:

Width at widest point, sidewall to sidewall, in millimeters

Aspect Ratio:

Tire height in mm, measured tread to bead, divided by width above, multiplied by one hundred.

Speed ratings:

Q - 100 mph 160kph

R - 106 mph 170kph

S - 112 mph 180kph

T - 118 mph 190kph

U - 124 mph 200kph

H - 130 mph 210kph

V - 149 mph 240kph

W - 168 mph 270kph

Z - more than 168 mph 270kph

Construction:

R - Radial ply

B - Bias belted

D - Diagonal bias

Size:

The diameter of the wheel the tire is designed to be mounted on, in inches.

Other information:

Maximum Air Pressure -

This is the max pressure the tire is designed to hold (note this is more than the recommended inflation pressure)

Maximum Load -

Weight the tire can support

Load Index -

A code that indicates the maximum weight the tire can carry at its speed indicated by its speed rating

Construction -

Tells the number and type of plies used in the construction of the tread and sidewall

DOT Serial Number -

Identifies the plant, manufacturer, and date of production

Tread Wear Index -

A rating of the tire's resistance to wear. 100 is the reference. A 250 rating indicates 2.5 times the wear resistance of the reference tire. This number cannot be accurately translated to mileage.

Traction Index -

A rating of the tire's ability to stop on wet pavement. There are three grades, A, B, and C, with A being the best. This index does not reflect the tire's traction performance on dry, snowy, or icy pavement.

Temperature Index -

A rating of the tire's ability to dissipate and resist heat. There are three grades, A, B, and C, with A being the best.