Playing the ‘Parking Lot I Spy’ game can teach you a lot about tyres

It is widely accepted that South Africans overspend on cars. So, if you are one of those boring people who would rather have some disposal income instead of just the vehicle of your dreams, it’s time you played the “Parking Lot, I Spy” game. The idea is to see who is driving a car they can’t afford. It is easy; you look at the tyres.

Look at the tyres for your clues

It’s incredible just how many of the luxury cars you would love to own have tyres whose treads are only a memory or are running brands that would make the vehicle’s manufacturer shudder.

You may not own one of those beautiful cars, but it is nice to go home knowing that whoever does, lives in perpetual fear of the government announcing a petrol price hike or an interest rate increase. 

The other benefit of the parking lot game is that it makes you more aware of those pieces of rubber that keep your most costly possession in contact with the road.

Everything you need to know is on the tyre sidewall. Some of this is reasonably valuable stuff- particularly those numbers that talk about the size, speed rating and load index. But let’s go back to the beginning.

As usual in the motor industry, there are standards. In the case of tyres, South Africa follows the European Tyre and Rim Technical Organisation (ETRTO) markings. (You needed to know that?)

Anyway, here you go.

Handy basic tyre information

A: This gives the width of the tyre in millimetres measured from sidewall to sidewall.

B: The aspect ratio of the tyre. This, says Goodyear, is the “ratio of the tyre’s cross-section to its width, expressed as a percentage”. An aspect ratio of 55, for example, indicates that the tyre’s height is 55% of its width.

The letter “R” tells you the tyre is a radial — the most common form of tyre construction used today.

Other examples are “B” for Bias-ply or “D” for Diagonal construction.

C: Wheel diameter, or height, of the wheel in inches.

D: This is the load index. It is essential because it tells you what the maximum carrying capacity of the tyre that is fitted. In the example used, the load index of 91 can carry 615kg of weight. The carrying capacity for each value is described in a load index chart in your vehicle or tyre documentation.

Overload the tyres and the consequences could be dire. Imagine an overloaded caravan that far exceeds the load index of its tyres finding out about this on a high-speed highway.

E: The final letter in the sequence indicates the maximum speed for a tyre that is correctly inflated and being used under load. A tyre with a speed rating of V, for example, has a maximum speed of 240 km/h.

If you are veteran parking lot voyeur, you could notice that a car’s owner has fitted tyres with a lower speed rating than you would expect from a vehicle of that type. This is a bad decision as the handling of the car can be affected, and safety is compromised.

The speed capability must be at least equivalent to the top speed of the vehicle to which it is fitted.

Other places to look

This is the primary information, but you may also find other data on a sidewall. The numbers and letters could run after the main sequence or be placed elsewhere. For the curious, and this is not a comprehensive list, they can include:

• DOT: This signifies that the tyre complies with Department of Transport requirements.
• SSR:  Self-supporting run-flat tyre
• MOE: In this case, the M refers to Mercedes Benz (another manufacturer would use a different letter) and the OE to original equipment
• M+S: Suitable for mud and snow
• XL: Extra-load
• AT: All-terrain
• TL: tubeless

When next you are in a supermarket’s parking lot and have time on your hands, do a tour. You will not only enjoy the informal car show but could leave with a new perspective on life.