What 225/45R17 means
The inputs are 225 mm nominal section width, a 45-percent aspect ratio, and a 17-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 225 × 45 ÷ 100 = 101.25 mm. Adding two sidewalls to the 431.8 mm rim gives 634.3 mm (24.97 in) of nominal outside diameter.
A calculated reference
The 101.25 mm sidewall is shared with 225/45R18, but the rim diameters differ. The curated comparison with 225/40R18 combines a larger rim with shorter sidewalls; the 225/50R17 comparison instead changes only the aspect ratio. The two operations have different geometric effects.
Using a perfect-circle model, circumference is 1992.71 mm, equivalent to 501.83 revolutions per kilometer or 807.61 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 225/45R17, article 15576370000. 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