What does tyre size mean?

To the untrained eye, the side wall of a tyre can look like a meaningless set of numbers, letters and symbols. Hidden amongst these is the tyre size. But what does it look like and, more importantly, what does it mean?

How the tyre size might appear.

Disecting the code

The tyre size might read like this: P195/55 R16 87 V. Hardly user friendly but, when you know what it all means, you’ll realise it tells you useful information about the tyre’s construction, size and type.

1 Cross section width

The first three numbers, in this case 195, refer to the section width of the tyre. This is the measurement, in millimetres, from the tyre’s inner sidewall to its outer sidewall.

2 Aspect ratio

The aspect ratio, or profile, refers to the height of the sidewall as a % of the section width. In our example, 55 means the height is equal to 55% of the 195mm width. The bigger the aspect ratio, the bigger the sidewall will be.

3 Construction type

The letter R means the tyre is a radial construction. Almost all new car tyres are radials.

4 Rim

The number to the right of the construction type is the rim diameter, measured in inches. In this case, it’s a 16” wheel.

5 Load index 

The final number is the load index i.e. the maximum load (in kg) that the tyre can carry. See chart below

Load IndexLoad in kgLoad IndexLoad in kgLoad IndexLoad in kgLoad IndexLoad in kg
6226579437967101131150
6327280450977301141180
6428081462987501151215
6529082475997751161250
66300834871008001171285
67307845001018251181320
68315855151028501191360
69325865301038751201400
70335875451049001211450
71345885601059251221500
72355895801069501231550
73365906001079751241600
743759161510810001251650
753879263010910301261700
76400936501101060

77412946701111090

78425956901121120


Tyre load rating table

6 Speed symbol

The final character (in this case V) relates to the maximum speed of use. Again, the following table will clarify what your tyre’s symbol means.


Speed RatingMile/HourKilometers/Hour
Speed RatingMile/HourKilometers/Hour
N87140
U124200
P93150
H130210
Q99160
V149240
R106170
ZR150+240+
S112180
W168270
T118190
Y186300


Tyre speed rating table

Where can I find my car’s tyre size?

You’ll find you car’s tyre size on the tyres’ sidewall, in your car’s vehicle manual as well as on a sticker inside the driver’s door. If you’re still unsure, visit your nearest Uniroyal dealership for advice.

Uniroyal. A brand of Continental.

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