GarageCalc What 245/60R18 means
245 is the section width in millimeters (9.6 in). 60 is the aspect ratio: the sidewall is 60 percent of the width, so 245 × 0.60 = 147 mm (5.8 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 × 147 = 751 mm, or 29.6 in.
A full marking adds a load index and speed rating after the size, for example 245/60R18 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 245/60R18
Going up one wheel size, the closest match is 245/55R19 at +0.1% diameter with a 135 mm sidewall instead of 147 mm. Going down one size, 245/65R17 is -0.1% with a taller 159 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 245/60R18
Typical factory fitments include Ford Explorer (2011-2019), Ford Edge, Toyota Highlander (2014-2019), Kia Telluride and Hyundai Palisade. Tire size changes with trim and wheel option, so confirm on the door-jamb placard before buying.
Frequently asked questions
How tall is a 245/60R18 tire?
29.6 inches (751 mm) in overall diameter: the 18-inch wheel (457 mm) plus two 147 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 245/60R18 in inches?
29.6 x 9.6 R18: 29.6 inches tall, 9.6 inches wide, on an 18-inch wheel. The sidewall is 5.8 inches and the circumference is 92.9 inches, so the tire turns 682 times per mile.
What tire sizes are equivalent to 245/60R18?
Within 3 percent of the same diameter on the same 18-inch wheel: 235/65R18 (+1.5%), 235/60R18 (-1.6%), 255/60R18 (+1.6%); on a 19-inch wheel: 245/55R19 (+0.1%), 265/50R19 (-0.5%); on a 17-inch wheel: 245/65R17 (-0.1%), 235/70R17 (+1.3%). The percentage is the diameter change, which is also your speedometer error.
Can I use 255/60R18 instead of 245/60R18?
Dimensionally yes: 255/60R18 is 1.6% taller (+12 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 59.1 mph. The extra width needs about 0.20 in of clearance on each side of the tire and a rim width that suits 255 mm.