GarageCalc What 235/60R18 means
235 is the section width in millimeters (9.3 in). 60 is the aspect ratio: the sidewall is 60 percent of the width, so 235 × 0.60 = 141 mm (5.6 in). R is radial construction, and 18 is the wheel diameter in inches (457 mm). Stack two sidewalls on the wheel and you get the overall diameter: 457 + 2 × 141 = 739 mm, or 29.1 in.
A full marking adds a load index and speed rating after the size, for example 235/60R18 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 235/60R18
Going up one wheel size, the closest match is 255/50R19 at -0.2% diameter with a 128 mm sidewall instead of 141 mm. Going down one size, 255/60R17 is -0.2% with a taller 153 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.
Which cars come with 235/60R18
Typical factory fitments include Honda CR-V EX and above (2017 on), Nissan Rogue SV (2021 on) and Hyundai Santa Fe (2019 on). Tire size changes with trim and wheel option, so confirm on the door-jamb placard before buying.
Frequently asked questions
How tall is a 235/60R18 tire?
29.1 inches (739 mm) in overall diameter: the 18-inch wheel (457 mm) plus two 141 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 235/60R18 in inches?
29.1 x 9.3 R18: 29.1 inches tall, 9.3 inches wide, on an 18-inch wheel. The sidewall is 5.6 inches and the circumference is 91.4 inches, so the tire turns 693 times per mile.
What tire sizes are equivalent to 235/60R18?
Within 3 percent of the same diameter on the same 18-inch wheel: 255/55R18 (-0.2%), 225/60R18 (-1.6%), 245/60R18 (+1.6%); on a 19-inch wheel: 255/50R19 (-0.2%), 235/55R19 (+0.3%); on a 17-inch wheel: 255/60R17 (-0.2%), 235/65R17 (-0.3%). The percentage is the diameter change, which is also your speedometer error.
Can I use 245/60R18 instead of 235/60R18?
Dimensionally yes: 245/60R18 is 1.6% taller (+12 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 59.0 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.