A ‘tyred’ look at wheels!

Understanding Tyre markings

Tyres have an alphanumeric code system printed / embedded into their sidewall which allows the common man to understand the technical capabilities of the tyre, irrespective of its manufacturer. 

Being able to read this information will help you maintain your tyres, and choose new ones when the time comes.

Needless to say, you would not be reading this if you didnt understand the basic fact that tyres save lives….. Remember noticing those shreds of tyres you see on our highways….. BLOWOUT ! the ever present danger to our lives on highways….. 

(Image Source : ATMA website) 

 

This code provides information on the tyre‘s construction (e.g. radial), its size, its load-carrying capacity and its speed rating.

For example, the code commonly seen on most cars may be such as this below :-

P 205 / 65 R 15 95 H

P or no letter at all indicates a passenger car tyre.

205 – Section Width

indicates the nominal section width of the tyre in millimeters (i.e 205mm).

65 – Aspect Ratio

indicates the tyre’s aspect ratio, a comparison of the tyre‘s section height with its section width (65 indicates the height is 65% of its width).

R – Radial

indicates radial ply construction.

15 – Rim Diameter

the nominal diameter of the wheel rim (15 inches)

95 – Load Rating

a symbol indicating the maximum load capacity at which the tyre can be safely operated.  95 represents a maximum load of 690 kg per tyre; 

Load Index	81	82	85	86	87	90	92	95	96
Max Load/tyre (kg)	462	475	515	530	545	600	630	690	710

Personal Experience

I have survived (with the blessings of the Almighty), two tyre bursts in succession, on a traipse across Northern Botswana in 2007. At high speeds that too…. 120kmph was the prescribed speed limit there.

My second burst tyre was “brand new” to look at, but possibly had nestled in the comfort of the dicky of the car in the sweltering clime of Singapore for all of three years!! Trivia nugget  – most second hand cars sold in Africa are from the South East Asian region, where it is apparently uneconomical to ply cars older than three years….!  To cut a long story short, in the succeeding paras, I shall endeavor to convey the essence of my recommendations from the Public Health perspective…. Anyway, you could invalidate your insurance when driving on ‘worn tyres’! 

A worn tyre will also reduce the effectiveness of your brakes, acceleration and steering. The deeper the tread the more grip you have. It is not just unsafe to ignore the minimum tyre tread depth, it is illegal in certain countries such as South Africa ! There is a legal minimum tread depth of 1.6 mm, for all four tyres on a car, and this can be checked and a fine imposed in South Africa. The way to check it crudely is to put the head of a matchstick in between the treads and if it stays put , the tread depth is ok. 

When buying a car second hand, always assume that the tyres are as old as the car is , however “new” they may look…… Rubber has an expiry date, a parallel example would be other household rubber goods, which are usually marked ” use before expiry and protect from sunlight and excessive pressure”! Your car tyres see a much tougher life in their journeys.You could also use the example of condoms, which when old get brittle and crack! Accordingly please consider buying new tyres as per the rating specifications of your car (check the Car Manual). The rating clearly indicates the maximum speed that your tyres can bear. 

For city driving you can soldier on with your old tyres, but when going on a long drive, consider the change of tyres as an investment in safety, for your family and you. The old info about tyre pressure and balancing / alignment still rings true…. so check your pressure  ( car tyre, and maybe once a year, your Blood Pressure too) regularly.

And get your tyres rotated and aligned / balanced every 10,000km. Tyre experts recommend changing tyres every 80,000 km or 2 years, whichever comes earlier, if you drive on highways. However please refer to your car manual for further info. 

While concluding , I must take this opportunity of advising you to “Buckle Up !!” that includes the passengers in the rear…..Research has proven that seat belts save lives, thats why these are there !  Children must never be allowed to sit in the front of a car without seat belts properly positioned, and just because it is not legally enforced, do not ignore child restraints in the rear of passenger cars. Safe motoring !