GarageCalc What 145/80R13 means
145 is the section width in millimeters (5.7 in). 80 is the aspect ratio: the sidewall is 80 percent of the width, so 145 × 0.80 = 116 mm (4.6 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 × 116 = 562 mm, or 22.1 in.
A full marking adds a load index and speed rating after the size, for example 145/80R13 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 145/80R13
Going up one wheel size, the closest match is 155/65R14 at -0.9% diameter with a 101 mm sidewall instead of 116 mm. Going down one size, 155/80R12 is -1.7% with a taller 124 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 145/80R13 tire?
22.1 inches (562 mm) in overall diameter: the 13-inch wheel (330 mm) plus two 116 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 145/80R13 in inches?
22.1 x 5.7 R13: 22.1 inches tall, 5.7 inches wide, on a 13-inch wheel. The sidewall is 4.6 inches and the circumference is 69.5 inches, so the tire turns 911 times per mile.
What tire sizes are equivalent to 145/80R13?
Within 3 percent of the same diameter on the same 13-inch wheel: 165/70R13 (-0.2%), 155/70R13 (-2.7%), 155/80R13 (+2.8%); on a 14-inch wheel: 155/65R14 (-0.9%), 165/65R14 (+1.4%); on a 12-inch wheel: 155/80R12 (-1.7%). The percentage is the diameter change, which is also your speedometer error.
Can I use 155/70R13 instead of 145/80R13?
Dimensionally yes: 155/70R13 is 2.7% shorter (-15 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 61.6 mph. The extra width needs about 0.20 in of clearance on each side of the tire and a rim width that suits 155 mm.