GarageCalc What 195/55R16 means
195 is the section width in millimeters (7.7 in). 55 is the aspect ratio: the sidewall is 55 percent of the width, so 195 × 0.55 = 107 mm (4.2 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 × 107 = 621 mm, or 24.4 in.
A full marking adds a load index and speed rating after the size, for example 195/55R16 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 195/55R16
Going up one wheel size, the closest match is 215/45R17 at +0.7% diameter with a 97 mm sidewall instead of 107 mm. Going down one size, 185/65R15 is +0.1% with a taller 120 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 195/55R16 tire?
24.4 inches (621 mm) in overall diameter: the 16-inch wheel (406 mm) plus two 107 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 195/55R16 in inches?
24.4 x 7.7 R16: 24.4 inches tall, 7.7 inches wide, on a 16-inch wheel. The sidewall is 4.2 inches and the circumference is 76.8 inches, so the tire turns 825 times per mile.
What tire sizes are equivalent to 195/55R16?
Within 3 percent of the same diameter on the same 16-inch wheel: 205/50R16 (-1.5%), 185/55R16 (-1.8%), 205/55R16 (+1.8%); on a 17-inch wheel: 215/45R17 (+0.7%), 205/45R17 (-0.7%); on a 15-inch wheel: 185/65R15 (+0.1%), 195/60R15 (-1.0%). The percentage is the diameter change, which is also your speedometer error.
Can I use 205/50R16 instead of 195/55R16?
Dimensionally yes: 205/50R16 is 1.5% shorter (-10 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 60.9 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.