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
Similar diameter does not establish interchangeability. Follow the vehicle manufacturer's approved sizes; see Michelin's tire-size guidance.
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. The 3 percent cutoff is a comparison filter, not a fitment approval. Use vehicle-approved sizes and check rim width, load and speed ratings, and clearances. The comparison calculator shows the full speedometer table for any pair.
For the effect on road speed and distance, see our worked speedometer example. When maintaining this set, use the rotation pattern guide to check whether tire direction or different front and rear sizes restrict rotation.
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. Actual dimensions depend on the tire model, tread depth, pressure and load; check the tire manufacturer specifications.
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%). These are nominal diameter comparisons, not approved replacements. Check vehicle-approved sizes, rim width, load and speed ratings, and clearance before changing size.