GarageCalc What 165/65R13 means
165 is the section width in millimeters (6.5 in). 65 is the aspect ratio: the sidewall is 65 percent of the width, so 165 × 0.65 = 107 mm (4.2 in). R is radial construction, and 13 is the wheel diameter in inches (330 mm). Stack two sidewalls on the wheel and you get the overall diameter: 330 + 2 × 107 = 545 mm, or 21.4 in.
A full marking adds a load index and speed rating after the size, for example 165/65R13 91V. Those two codes set how much weight and speed the tire is certified for; look them up in the load index chart and the speed rating chart.
Plus and minus sizing from 165/65R13
Going up one wheel size, the closest match is 165/60R14 at +1.6% diameter with a 99 mm sidewall instead of 107 mm. Going down one size, 145/80R12 is -1.5% with a taller 116 mm sidewall for more comfort and pothole margin. Anything inside 3 percent keeps the speedometer, ABS and gearing effectively stock; the comparison calculator shows the full speedometer table for any pair.
Frequently asked questions
How tall is a 165/65R13 tire?
21.4 inches (545 mm) in overall diameter: the 13-inch wheel (330 mm) plus two 107 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 165/65R13 in inches?
21.4 x 6.5 R13: 21.4 inches tall, 6.5 inches wide, on a 13-inch wheel. The sidewall is 4.2 inches and the circumference is 67.4 inches, so the tire turns 940 times per mile.
What tire sizes are equivalent to 165/65R13?
Within 3 percent of the same diameter on the same 13-inch wheel: 155/70R13 (+0.5%), 185/60R13 (+1.4%), 145/70R13 (-2.1%); on a 14-inch wheel: 165/60R14 (+1.6%), 155/65R14 (+2.3%); on a 12-inch wheel: 145/80R12 (-1.5%), 155/80R12 (+1.5%). The percentage is the diameter change, which is also your speedometer error.
Can I use 175/65R13 instead of 165/65R13?
Dimensionally yes: 175/65R13 is 2.4% taller (+13 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 58.6 mph. The extra width needs about 0.20 in of clearance on each side of the tire and a rim width that suits 175 mm.