Best Tire Buying Guide – Consumer Reports

Tires have a wealth of information encoded on their sidewalls. When replacing them, we recommend staying with the size and speed rating of your car’s original tires. Check your owner’s manual for more information.

Size: On the tire below, 235 is the cross-section width in millimeters; 65 is the ratio of sidewall height to its width (65 percent); R indicates radial-ply construction; and 17 is the wheel rim’s diameter in inches.

Load index: Shorthand for the maximum weight each tire can safely carry when properly inflated. The 94 here means 1,477 pounds per tire—pretty typical for a midsized car tire.

Speed rating: A letter denoting the tire’s maximum speed when carrying the load defined by the load index—and not how fast you should drive! Standard all-seasons are usually rated T (118 mph) or H (130 mph). Climbing up the scale are V (149 mph), ZR (149-plus mph), W (168 mph), and Y (186 mph) ratings. Winter tires may carry the letter R (106 mph) or higher.

Treadwear grade: A government-required number that indicates a tire’s expected wear. A grade of 300 denotes a tire that will wear three times as well as a tire graded 100. But the numbers are assigned by tire manufacturers, not an independent third party.

Traction and temperature scores: These scores denote a tire’s wet-stopping ability and temperature resistance. For traction, AA is best and C is worst. For temperature resistance, scores range from A (best) to C.

Manufacture date code: Every tire has a Department of Transportation number after the letters on the sidewall. The last four digits show the week and year the tire was made; for example, the digits 2321 would signify that the tire was made during the 23rd week of 2021. Don’t buy tires more than a couple of years old.