GarageCalc What 285/35R22 means
285 is the section width in millimeters (11.2 in). 35 is the aspect ratio: the sidewall is 35 percent of the width, so 285 × 0.35 = 100 mm (3.9 in). R is radial construction, and 22 is the wheel diameter in inches (559 mm). Stack two sidewalls on the wheel and you get the overall diameter: 559 + 2 × 100 = 758 mm, or 29.9 in.
A full marking adds a load index and speed rating after the size, for example 285/35R22 91V. Those two codes set how much weight and speed the tire is certified for; look them up in the load index chart and the speed rating chart.
Plus and minus sizing from 285/35R22
No common 23-inch size stays within 3 percent of 29.9 in. Going down one size, 285/40R21 is +0.4% with a taller 114 mm sidewall for more comfort and pothole margin. Anything inside 3 percent keeps the speedometer, ABS and gearing effectively stock; the comparison calculator shows the full speedometer table for any pair.
Frequently asked questions
How tall is a 285/35R22 tire?
29.9 inches (758 mm) in overall diameter: the 22-inch wheel (559 mm) plus two 100 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 285/35R22 in inches?
29.9 x 11.2 R22: 29.9 inches tall, 11.2 inches wide, on a 22-inch wheel. The sidewall is 3.9 inches and the circumference is 93.8 inches, so the tire turns 676 times per mile.
What tire sizes are equivalent to 285/35R22?
Within 3 percent of the same diameter on the same 22-inch wheel: 265/40R22 (+1.6%), 265/35R22 (-1.8%), 275/40R22 (+2.7%); on a 21-inch wheel: 285/40R21 (+0.4%), 275/40R21 (-0.6%). The percentage is the diameter change, which is also your speedometer error.