Tyre Sidewalls - What does it all mean?

Tyre sidewalls are a strange creation. Words, acronyms, numbers, letters and symbols adorn the side of each tyre. Fortunately, only a small portion of the sidewall is of any relevance when it comes to replacing a tyre.

Key information - 195/65 r15 91v

195	The width of the tyre in MM
65	The aspect ratio of the tyre as a percentage of the width. In this case the sidewall is 45% of 205mm, or 92.25mm
R	Radial construction, as all modern tyres are
15	The size of the wheel in inches
91	The load index of the tyre in kgs (see table 1)
V	The speed index of the tyre (see table 2)

Other useful information

E13	The E-Marking.
XL	Denotes whether the tyre is an extra load version
Date of manufacture	The recommend life for a tyre is around 6 years (depending on storage conditions.) The first 2 numbers in the date code refer to the week the tyre was made, and the 3rd and 4th numbers refer to the year
Rotation direction	If the tyre is directional this shows which way the tyre should rotate when mounted
Side	If the tyre is asymmetric the tyre will have 'inside' or 'outside' printed on the tyre wall, showing which way round it should be mounted on the car.
US Consumer information	Treadwear, traction and temperature are rated on the side walls. These values can only be used as a comparison for tyres within the same brand as there is no common reference between brands.