GarageCalc What 215/65R15 means
215 is the section width in millimeters (8.5 in). 65 is the aspect ratio: the sidewall is 65 percent of the width, so 215 × 0.65 = 140 mm (5.5 in). R is radial construction, and 15 is the wheel diameter in inches (381 mm). Stack two sidewalls on the wheel and you get the overall diameter: 381 + 2 × 140 = 661 mm, or 26.0 in.
A full marking adds a load index and speed rating after the size, for example 215/65R15 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 215/65R15
Going up one wheel size, the closest match is 215/60R16 at +0.6% diameter with a 129 mm sidewall instead of 140 mm. Going down one size, 215/70R14 is -0.6% with a taller 151 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 215/65R15 tire?
26.0 inches (661 mm) in overall diameter: the 15-inch wheel (381 mm) plus two 140 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 215/65R15 in inches?
26.0 x 8.5 R15: 26.0 inches tall, 8.5 inches wide, on a 15-inch wheel. The sidewall is 5.5 inches and the circumference is 81.7 inches, so the tire turns 776 times per mile.
What tire sizes are equivalent to 215/65R15?
Within 3 percent of the same diameter on the same 15-inch wheel: 235/60R15 (+0.4%), 195/70R15 (-1.0%), 205/70R15 (+1.1%); on a 16-inch wheel: 215/60R16 (+0.6%), 225/55R16 (-1.0%); on a 14-inch wheel: 215/70R14 (-0.6%), 205/70R14 (-2.7%). The percentage is the diameter change, which is also your speedometer error.
Can I use 225/60R15 instead of 215/65R15?
Dimensionally yes: 225/60R15 is 1.4% shorter (-10 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 60.9 mph. The extra width needs about 0.20 in of clearance on each side of the tire and a rim width that suits 225 mm.