What 265/60R18 means
The inputs are 265 mm nominal section width, a 60-percent aspect ratio, and an 18-inch nominal rim diameter. The R identifies radial construction. The width is not a wheel-width measurement, and the rim number is not the outside diameter of the tire.
Nominal sidewall height is 265 × 60 ÷ 100 = 159 mm. Adding two sidewalls to the 457.2 mm rim gives 775.2 mm (30.52 in) of nominal outside diameter.
A calculated reference
The 18-inch rim does not make this marking larger overall than 265/70R17. Its 159 mm sidewall is shorter by 26.5 mm per side; those two reductions exceed the added 25.4 mm of rim diameter.
Using a perfect-circle model, circumference is 2435.36 mm, equivalent to 410.62 revolutions per kilometer or 660.82 per mile. These are derived from unrounded diameter; actual rolling circumference also depends on the product and operating conditions.
Source and scope
General Tire’s Grabber APT source includes 265/60 R 18, article 04508080000. It was checked on October 27, 2026. That record verifies the published marking used here; it does not turn these calculated dimensions into that product’s measured specification or establish availability.
Use the exact product and vehicle requirements for load and speed ratings, permitted rim dimensions, inflation and clearance. Nominal geometry alone cannot verify fitment, braking behavior, handling or safety.
Sources and further reading
- Grabber APT — Specifications — General Tire
- Tire Markings Explained — Michelin
- Tire glossary — Michelin