GarageCalc What 265/70R15 means
265 is the section width in millimeters (10.4 in). 70 is the aspect ratio: the sidewall is 70 percent of the width, so 265 × 0.70 = 186 mm (7.3 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 × 186 = 752 mm, or 29.6 in.
A full marking adds a load index and speed rating after the size, for example 265/70R15 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 265/70R15
Going up one wheel size, the closest match is 245/70R16 at -0.3% diameter with a 172 mm sidewall instead of 186 mm. No common 14-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 265/70R15 tire?
29.6 inches (752 mm) in overall diameter: the 15-inch wheel (381 mm) plus two 186 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 265/70R15 in inches?
29.6 x 10.4 R15: 29.6 inches tall, 10.4 inches wide, on a 15-inch wheel. The sidewall is 7.3 inches and the circumference is 93.0 inches, so the tire turns 681 times per mile.
What tire sizes are equivalent to 265/70R15?
Within 3 percent of the same diameter on the same 15-inch wheel: 255/70R15 (-1.9%); on a 16-inch wheel: 245/70R16 (-0.3%), 255/70R16 (+1.5%). The percentage is the diameter change, which is also your speedometer error.