GarageCalc What 225/60R15 means
225 is the section width in millimeters (8.9 in). 60 is the aspect ratio: the sidewall is 60 percent of the width, so 225 × 0.60 = 135 mm (5.3 in). R is radial construction, and 15 is the wheel diameter in inches (381 mm). Stack two sidewalls on the wheel and you get the overall diameter: 381 + 2 × 135 = 651 mm, or 25.6 in.
A full marking adds a load index and speed rating after the size, for example 225/60R15 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 225/60R15
Going up one wheel size, the closest match is 205/60R16 at +0.2% diameter with a 123 mm sidewall instead of 135 mm. Going down one size, 215/70R14 is +0.9% with a taller 151 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 225/60R15 tire?
25.6 inches (651 mm) in overall diameter: the 15-inch wheel (381 mm) plus two 135 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 225/60R15 in inches?
25.6 x 8.9 R15: 25.6 inches tall, 8.9 inches wide, on a 15-inch wheel. The sidewall is 5.3 inches and the circumference is 80.5 inches, so the tire turns 787 times per mile.
What tire sizes are equivalent to 225/60R15?
Within 3 percent of the same diameter on the same 15-inch wheel: 205/65R15 (-0.5%), 215/65R15 (+1.5%), 215/60R15 (-1.8%); on a 16-inch wheel: 205/60R16 (+0.2%), 225/55R16 (+0.4%); on a 14-inch wheel: 215/70R14 (+0.9%), 205/70R14 (-1.3%). The percentage is the diameter change, which is also your speedometer error.
Can I use 235/60R15 instead of 225/60R15?
Dimensionally yes: 235/60R15 is 1.8% taller (+12 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 58.9 mph. The extra width needs about 0.20 in of clearance on each side of the tire and a rim width that suits 235 mm.