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Tires 101

Tires 101

Tires are a critical component of your vehicle. Proper tire maintenance is important in extending the life of your tires and keeping your car running safely down the road.

Tires 101

Tread: the part of a tire that makes contact with the ground. Tread is molded into patterns, which contain grooves in the rubber designed to increase friction and expel water from beneath the tire to prevent hydroplaning.

Handling: describes the responsiveness of a tire to steering inputs.

All-season tires: Tires made for a variety of road conditions.

PSI: Pounds per square inch; used as a measurement of tire inflation pressure. Learn more in our Tire Video.

Circumferential grooves: grooves in the rubber of your tires arranged in a straight line around the circumference of the tire. These disperse water by cutting through it. Circumferential grooves in your tire help you have low rolling resistance, resistance to cupping, good rain traction, a smooth, quiet ride. However, these tires aren’t as reliable in snow and dirt.

Cupping: scalloped dips around the edge of the tread on one side or the other which usually indicates worn or bent suspension parts.

Tread wear: the inevitable result of driving on your tires, over time the friction between the tire and the road wears the rubber away; irregular tread wear patterns can be caused by larger problems like misalignment and under- or over-inflation.

Sidewall: the side of the tire; the part of the tire which does not make contact with the ground.

Siping: a series of slits in the tread of winter tires used to increase the number of edges that make contact with the ground to give your car more traction on ice and snow.

Rim: the portion of the wheel to which a tire is mounted.

Speed rating: alphabetical code which refers to the maximum speed a tire can handle as rated by the tire manufacturer.

Studded tires: designed to increase a tire’s traction on ice, studded tires contain hard metal or plastic devices for better grip. Check your state’s regulations to see if you’re permitted to use them in your state.

Snow chains: flexible metal chains that attach to tires to give better grip in the snow.

Uniform Tire Quality Grading (UTQG): printed on the sidewall, a tire’s UTQG consists of three factors and is assigned by the tire manufacturer. UTQG is listed as follows: Treadwear XXX Traction X Temperature X. These ratings can be compared within the same brand but not across brands.

Treadwear: the numeric portion of the UTQG, the tread wear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test track. Tread wear grades are not a guarantee of actual tire mileage as factors such as driving habits, climate and road characteristics impact tire longevity.

Traction: traction grades range from AA – C, with AA being the highest and C being the lowest. These grades represent the tire’s ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. The testing does not take into account cornering, hydroplaning or acceleration.

Temperature: temperature grades range from A – C with A being the highest and C being the lowest. These grades represent the tire’s resistance to the generation of heat at speed. 

Tire size: see full article at “Tire Size: Decoded”

DOT code: (Department of Transportation) all tires for use in the United States have a DOT code specifying the company, factory, mold, batch and date of production of the tire. The date of production is listed as such: two digits for week of the year plus two digits for year, or two digits for week of the year plus one digit for year for tires made prior to 2000 (example: 2204 represents a tire manufactured in the 22nd week of 2004).

Winter tires: tires designed specifically for extreme cold temperatures and for use in snowy or icy conditions.

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