GarageCalc What 235/75R16 means
235 is the section width in millimeters (9.3 in). 75 is the aspect ratio: the sidewall is 75 percent of the width, so 235 × 0.75 = 176 mm (6.9 in). R is radial construction, and 16 is the wheel diameter in inches (406 mm). Stack two sidewalls on the wheel and you get the overall diameter: 406 + 2 × 176 = 759 mm, or 29.9 in.
A full marking adds a load index and speed rating after the size, for example 235/75R16 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 235/75R16
Going up one wheel size, the closest match is 235/70R17 at +0.3% diameter with a 165 mm sidewall instead of 176 mm. Going down one size, 255/70R15 is -2.8% with a taller 179 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 235/75R16 tire?
29.9 inches (759 mm) in overall diameter: the 16-inch wheel (406 mm) plus two 176 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 235/75R16 in inches?
29.9 x 9.3 R16: 29.9 inches tall, 9.3 inches wide, on a 16-inch wheel. The sidewall is 6.9 inches and the circumference is 93.9 inches, so the tire turns 675 times per mile.
What tire sizes are equivalent to 235/75R16?
Within 3 percent of the same diameter on the same 16-inch wheel: 255/70R16 (+0.6%), 245/70R16 (-1.3%), 225/75R16 (-2.0%); on a 17-inch wheel: 235/70R17 (+0.3%), 255/65R17 (+0.6%); on a 15-inch wheel: 255/70R15 (-2.8%). The percentage is the diameter change, which is also your speedometer error.
Can I use 245/70R16 instead of 235/75R16?
Dimensionally yes: 245/70R16 is 1.3% shorter (-10 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 60.8 mph. The extra width needs about 0.20 in of clearance on each side of the tire and a rim width that suits 245 mm.