TYRE 101 - KNOW YOUR TYRE
TIRE LABELING
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Tire Type
P = Passenger LT = Light Truck T = Temporary spare ST = Special trailers
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Tire Width
3-digit number that gives the approximate tire width in mm. It measures from sidewall to sidewall.
Typically, the higher the number the larger the tire.
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Aspect Ratio
2-digit number that gives the approximate sidewall height. It is expressed as a % of the tire width.
The lower the ratio, the smaller the sidewall height.
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Construction
R = Radial Ply B = Bias Ply
Radial tires are the industry standard and refers to the internal belts being 90 degrees to the direction of travel
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Wheel Diameter
2-digit number (in inches) that indicates the tire is designed to fit on a wheel with a 16-inch diameter.
Load Index
2-digit number that indicates how much weight the tire is certified to carry at maximum safe inflation.
Speed Rating
1 letter or 1 letter/number combo which indicates the top speed at which a tire is certified under specified conditions.