Tyre Sizes
Tyre sizes are made up of a number of different numbers and letters. For example tyre size 175/70 R 13 82 T is made up of the following information:

175: This is the tyre section width in millimetres
70: This is the aspect ratio in % (the height of the sidewall divided by the tyre's width)
R: This denotes the tyre's construction type - in this case it's a radial
13: This is the rim diameter in inches
82: This is the load index
T: This is the speed rating


Tyre Age Tyres carry a three digit age code on the sidewall indicating the month and year of manufacture. For example 129 means the tyre was manufactured in December 1999.