A ‘tyred’ look at wheels!

Dear Reader,
 
As it nears the end of 2018, let me narrate a wee tale of tyres, before you get all ‘tired’ from the year end wisdom (gyaan) that would be inundating you.
 
Read on, in case you are wondering about what I am rambling about….. read about tyre specifications , with those mysterious alphanumeric codes on your tyre (did you notice them ever?).

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….. 
How to read a tyre
(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
 
H – Speed Rating
is a symbol indicating the maximum speed at which the tyre can be safely operated, subject to the tyre being in sound condition, correctly fitted, and with recommended inflation pressures. Here H represents a maximum speed of 210 kmph,

Speed Symbol

Max Speed Capability(Km/h)

Speed Symbol

Max Speed Capability(Km/h)

L

120

T

190

M

130

U

200

N

140

H

210

P

150

V

240

Q

160

W

270

R

170

Y

300

S

180

Z

240+

Production Date
The date your tyre was produced is indicated by a four-digit code showing the week and the year.
Tread Wear Indicators
The letters “TWI” show the location of the tyre’s tread wear indicators. You should check these indicators regularly to ensure the tread is sufficiently deep. The minimum tread depth is in most cases 1.6mm. Please refer to your Car Manual to locate this TWI or look closely at the photo below:- 
 
Tyres may look good and look “like new”, which is what I assumed that mine were  OK.
 
 
 
 
Entering the Madikwe Game Reserve in Southern Africa, 2008 – Nissan Sunny
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 !

Published by Delta Zulu Consultancy

I am a Public Health Specialist with a passion for sustainable promotion of human co-existence with the environment! My areas of interest and expertise are Health Risk Communication and Community Engagement, Food Safety, Environmental Medicine and Mass Gathering Medicine. I believe in leveraging the power of technology to capture the imagination of people to inspire them to achieve their health potential, in a sustainable manner. I aspire to empower my partners and motivate stake holders to consistently seek 'work around' solutions, while hoping to achieve an utopian ideal balance.

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