The Tyre Codes

30-October-2007

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What exactly do the splutters of numbers and letters mean on your tyre's sidewall (the side part)? Here's where we break it down...

What it all means

Let's say the tyre has "205/50r16 87y" written on it...

205 is the maximum section width in millimetres, with the tyre inflated to its normal pressure.

50 refers to the 'profile', the 'aspect ratio' or the 'series' (aka the height of the sidewall divided by the section, as a percentage). To give you more of an idea what that actually means, supercars usually have 30-35 while the average car has 50-55.

R is for radial (meaning, a modern way of making a tyre, as opposed to the old-school way of cross-ply construction).

16 is the rim diameter.

87 is the load index rating (how much weight the tyre can handle). You should never fit a tyre with a load rating less than the one written on the tyre placard (a silver plate fitted inside the door frame or glovebox that also tells you the appropriate inflation pressures).

Y is the speed rating (the maximum speed recommended for the tyres). The common ones are: h (210 km/h), V (240 km/h), W (270 km/h), Y and Z (both 300 km/h).

Tyres also incorporate a 12-digit serial code that tells you which country it was manufactured in, the size of the tyre, manufacturer's mode, and the week and year of it was made.

Source & more info

Visit www.crashprevention.com.au for the latest tyre and safety information.
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