What 195/60R15 means
The inputs are 195 mm nominal section width, a 60-percent aspect ratio, and a 15-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 195 × 60 ÷ 100 = 117 mm. Adding two sidewalls to the 381 mm rim gives 615 mm (24.21 in) of nominal outside diameter.
A calculated reference
The 60-percent calculation produces 117 mm of sidewall, not 60 mm. Keeping the units visible prevents the common mistake of adding the aspect-ratio number directly to rim diameter.
Using a perfect-circle model, circumference is 1932.08 mm, equivalent to 517.58 revolutions per kilometer or 832.96 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 AltiMAX RT45 source includes 195/60R15, article 15576120000. 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
- AltiMAX RT45 — General Tire
- Tire Markings Explained — Michelin
- Tire glossary — Michelin