GarageCalc What 275/70R16 means
275 is the section width in millimeters (10.8 in). 70 is the aspect ratio: the sidewall is 70 percent of the width, so 275 × 0.70 = 193 mm (7.6 in). R is radial construction, and 16 is the wheel diameter in inches (406 mm). Stack two sidewalls on the wheel and you get the overall diameter: 406 + 2 × 193 = 791 mm, or 31.2 in.
A full marking adds a load index and speed rating after the size, for example 275/70R16 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 275/70R16
Going up one wheel size, the closest match is 275/65R17 at -0.3% diameter with a 179 mm sidewall instead of 193 mm. No common 15-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 275/70R16 tire?
31.2 inches (791 mm) in overall diameter: the 16-inch wheel (406 mm) plus two 193 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 275/70R16 in inches?
31.2 x 10.8 R16: 31.2 inches tall, 10.8 inches wide, on a 16-inch wheel. The sidewall is 7.6 inches and the circumference is 97.9 inches, so the tire turns 647 times per mile.
What tire sizes are equivalent to 275/70R16?
Within 3 percent of the same diameter on the same 16-inch wheel: 265/75R16 (+1.6%), 265/70R16 (-1.8%); on a 17-inch wheel: 275/65R17 (-0.3%), 255/70R17 (-0.3%). The percentage is the diameter change, which is also your speedometer error.