GarageCalc What 165/80R13 means
165 is the section width in millimeters (6.5 in). 80 is the aspect ratio: the sidewall is 80 percent of the width, so 165 × 0.80 = 132 mm (5.2 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 × 132 = 594 mm, or 23.4 in.
A full marking adds a load index and speed rating after the size, for example 165/80R13 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 165/80R13
Going up one wheel size, the closest match is 185/65R14 at +0.3% diameter with a 120 mm sidewall instead of 132 mm. No common 12-inch size stays within 3 percent either. 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 165/80R13 tire?
23.4 inches (594 mm) in overall diameter: the 13-inch wheel (330 mm) plus two 132 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 165/80R13 in inches?
23.4 x 6.5 R13: 23.4 inches tall, 6.5 inches wide, on a 13-inch wheel. The sidewall is 5.2 inches and the circumference is 73.5 inches, so the tire turns 862 times per mile.
What tire sizes are equivalent to 165/80R13?
Within 3 percent of the same diameter on the same 13-inch wheel: 185/70R13 (-0.8%), 155/80R13 (-2.7%); on a 14-inch wheel: 185/65R14 (+0.3%), 175/70R14 (+1.1%). The percentage is the diameter change, which is also your speedometer error.
Can I use 185/70R13 instead of 165/80R13?
Dimensionally yes: 185/70R13 is 0.8% shorter (-5 mm) and 20 mm wider, and at a true 60 mph the speedometer would read 60.5 mph. The extra width needs about 0.39 in of clearance on each side of the tire and a rim width that suits 185 mm.