GarageCalc What 215/45R17 means
215 is the section width in millimeters (8.5 in). 45 is the aspect ratio: the sidewall is 45 percent of the width, so 215 × 0.45 = 97 mm (3.8 in). R is radial construction, and 17 is the wheel diameter in inches (432 mm). Stack two sidewalls on the wheel and you get the overall diameter: 432 + 2 × 97 = 625 mm, or 24.6 in.
A full marking adds a load index and speed rating after the size, for example 215/45R17 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 215/45R17
Going up one wheel size, the closest match is 235/35R18 at -0.6% diameter with a 82 mm sidewall instead of 97 mm. Going down one size, 195/55R16 is -0.7% with a taller 107 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 215/45R17
Typical factory fitments include Honda Civic Si (2012-2015), Toyota Corolla S and SE (2014-2019) and Hyundai Elantra Limited (2011-2016). Tire size changes with trim and wheel option, so confirm on the door-jamb placard before buying.
Frequently asked questions
How tall is a 215/45R17 tire?
24.6 inches (625 mm) in overall diameter: the 17-inch wheel (432 mm) plus two 97 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 215/45R17 in inches?
24.6 x 8.5 R17: 24.6 inches tall, 8.5 inches wide, on a 17-inch wheel. The sidewall is 3.8 inches and the circumference is 77.3 inches, so the tire turns 819 times per mile.
What tire sizes are equivalent to 215/45R17?
Within 3 percent of the same diameter on the same 17-inch wheel: 235/40R17 (-0.9%), 205/45R17 (-1.4%), 225/45R17 (+1.4%); on an 18-inch wheel: 235/35R18 (-0.6%), 215/40R18 (+0.6%); on a 16-inch wheel: 195/55R16 (-0.7%), 225/50R16 (+1.0%). The percentage is the diameter change, which is also your speedometer error.
Can I use 225/45R17 instead of 215/45R17?
Dimensionally yes: 225/45R17 is 1.4% taller (+9 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 225 mm.