Sidewall Markings

Tire size is the most important information given on the tire. The size designation is specified as a series of numbers and letters, for example, 205/55 R 16 94 V XL, where:

205 is the width of the tire in mm
55 is the aspect ratio (height to width ratio)
R denotes radial construction
16 is the rim diameter in inches
94 is the load index
V is the speed rating.
XL Extra load capacity.

The speed rating shows the maximum continuous driving speed capability of the tire. The speed rating to be selected depends on the make and model of your car. The use of tires with speed ratings that are too low can affect the driving performance and tires with speed ratings that are too high may reduce driving comfort.

The most important speed ratings are:

Q = 99 mp/h / 160 km/h     
R = 106 mp/h / 170 km/h
S = 112 mp/h / 180 km/h
T = 118 mp/h / 190 km/h
H = 130 mp/h / 210 km/h
V = 149 mp/h / 240 km/h
W = 168 mp/h / 270 km/h
Y = 186 mp/h / 300 km/h 

Are you confused by the tire information in your car's registration document? Here's how to read it properly

Does the sequence 205/55 R 16 94 V XL say anything to you? You can find this alphabet soup in your registration document, and it will tell you the type of summer tire that fits your car. However, registration documents often contain several tire choices, allowing the driver to choose one based on whether they value driving comfort or a sensitive steering feel, for example. Read below for information that you should take into account to find tires that are right for you.