225/70R15 designates a tire 225 mm (8.9") wide with a sidewall 70% as tall as it is wide — about 158 mm (6.2") — mounted on a 15-inch wheel. That works out to an overall diameter of roughly 27.4", a circumference of about 86.1", and approximately 736 revolutions per mile. Exact figures vary slightly by manufacturer and tread design.
Of the 28 225/70R15 tire models we track, the most common category is highway all-season truck (8 models), followed by grand touring all-season (5) — a good indicator of the kind of vehicles and driving this size is designed for.