What 185/70R14 means
The inputs are 185 mm nominal section width, a 70-percent aspect ratio, and a 14-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 185 × 70 ÷ 100 = 129.5 mm. Adding two sidewalls to the 355.6 mm rim gives 614.6 mm (24.2 in) of nominal outside diameter.
A calculated reference
The 70-percent ratio makes the two nominal sidewalls total 259 mm. That term is separate from the 355.6 mm rim contribution. A large sidewall contribution to geometry does not by itself quantify ride comfort, durability or load capacity.
Using a perfect-circle model, circumference is 1930.82 mm, equivalent to 517.91 revolutions per kilometer or 833.5 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 185/70R14, article 15576100000. 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