Tyres are important components of any vehicle. The stability of the vehicle depends, among other things, on the integrity of the tyres it’s seating on. The joy or the discomfiture of a ride cannot be separated from the condition of the tyres.
Tyres conventionally carry a lot of valuable information on its outer body: the number beside the “psi” indicates the maximum number of air pressure that must be pumped into the tyre. But it’s better to give emphasis to the vehicle’s manufacturer’s recommended psi (which can be found on the plate sticker usually attached to the driver’s side door-post) instead of the tyre’s manufacturer’s specification that’s spelt out on it.

Tyres also bear a 4-digit numerical mark that states the week and the year of their manufacture (for example, “4106” means the forty-first week, “41”, of the year two thousand and six, “06”). This information is very important; the life span of tyres, either they’re put to use or not used at all, is five years. So, if tyres are ostensibly looking totally new, indeed if they’ve never been used at all, but if it’s five years old, it’s already bad.

The climate in which tyres can be used is also usually specified on the tyres. There are tyres with the mark stating that they should only be used in wintery weather; these must not be used in tropical regions of the world. Other vital indicators like the alphanumeric signage that states the nominal section width of the tyre, say, “165”, stroke the “aspect ratio”, i.e. the height of the tyre sidewall as a percentage of the nominal section width, “65”, with “R” radial construction, and, “14”, the diameter of the tyre’s inner rim in inches. All these coming out as “165/65R14”, are also important in deciding which tyre to buy for a vehicle and a defined purpose.

The information that is seldom understood and adhered to is the load capacity of a tyre, say “79” on the attached picture below, and the tyre speed rating­-i.e. the maximum speed for the tyre at full load-usually depicted as an alphabetical letter, “T” in our pictorial sample (- M: 81mph or 130 km/h, – N: 87 mph or 140 km/h, – P: 93 mph or 150 km/h, – Q: 99 mph or 160 km/h, – R: 106 mph or 170 km/h, – S: 112 mph or 180 km/h, – T: 118 mph or 190 km/h, – U: 124 mph or 200 km/h, – H: 130 mph or 210 km/h, – V: 149 mph or 240 km/h, – Z: in excess of 149 mph or 240 km/h plus, – W: 168 mph or 270 km/h, – Y: 186 mph or 300 km/h), should reasonably be subjected to.