GarageCalc What 155/65R14 means
155 is the section width in millimeters (6.1 in). 65 is the aspect ratio: the sidewall is 65 percent of the width, so 155 × 0.65 = 101 mm (4.0 in). R is radial construction, and 14 is the wheel diameter in inches (356 mm). Stack two sidewalls on the wheel and you get the overall diameter: 356 + 2 × 101 = 557 mm, or 21.9 in.
A full marking adds a load index and speed rating after the size, for example 155/65R14 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 155/65R14
Going up one wheel size, the closest match is 175/50R15 at -0.2% diameter with a 88 mm sidewall instead of 101 mm. Going down one size, 175/65R13 is +0.1% with a taller 114 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 155/65R14 tire?
21.9 inches (557 mm) in overall diameter: the 14-inch wheel (356 mm) plus two 101 mm sidewalls. Real tires land within about 1 to 2 percent of that depending on brand, tread depth and pressure.
What is 155/65R14 in inches?
21.9 x 6.1 R14: 21.9 inches tall, 6.1 inches wide, on a 14-inch wheel. The sidewall is 4.0 inches and the circumference is 68.9 inches, so the tire turns 920 times per mile.
What tire sizes are equivalent to 155/65R14?
Within 3 percent of the same diameter on the same 14-inch wheel: 165/60R14 (-0.6%), 175/60R14 (+1.5%), 165/65R14 (+2.3%); on a 15-inch wheel: 175/50R15 (-0.2%), 155/60R15 (+1.8%); on a 13-inch wheel: 175/65R13 (+0.1%), 165/70R13 (+0.7%). The percentage is the diameter change, which is also your speedometer error.
Can I use 165/60R14 instead of 155/65R14?
Dimensionally yes: 165/60R14 is 0.6% shorter (-4 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 60.4 mph. The extra width needs about 0.20 in of clearance on each side of the tire and a rim width that suits 165 mm.