GarageCalc What 195/45R16 means
195 is the section width in millimeters (7.7 in). 45 is the aspect ratio: the sidewall is 45 percent of the width, so 195 × 0.45 = 88 mm (3.5 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 × 88 = 582 mm, or 22.9 in.
A full marking adds a load index and speed rating after the size, for example 195/45R16 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 195/45R16
Going up one wheel size, the closest match is 205/40R17 at +2.4% diameter with a 82 mm sidewall instead of 88 mm. Going down one size, 185/55R15 is +0.4% with a taller 102 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 195/45R16 tire?
22.9 inches (582 mm) in overall diameter: the 16-inch wheel (406 mm) plus two 88 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 195/45R16 in inches?
22.9 x 7.7 R16: 22.9 inches tall, 7.7 inches wide, on a 16-inch wheel. The sidewall is 3.5 inches and the circumference is 72.0 inches, so the tire turns 880 times per mile.
What tire sizes are equivalent to 195/45R16?
Within 3 percent of the same diameter on the same 16-inch wheel: 205/45R16 (+1.5%), 185/50R16 (+1.6%); on a 17-inch wheel: 205/40R17 (+2.4%); on a 15-inch wheel: 185/55R15 (+0.4%), 205/50R15 (+0.7%). The percentage is the diameter change, which is also your speedometer error.
Can I use 205/45R16 instead of 195/45R16?
Dimensionally yes: 205/45R16 is 1.5% 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 205 mm.