Trivia about Car Tyres - Fun Facts on Wheels

Car tyres might seem to be pretty mundane things but a little research reveals some fascinating facts and figures about them…

The first inflatable tyre was made of leather

In 1887 John Boyd Dunlop developed the first practical pneumatic tyres; not a car tyres but ones for use on his son’s bicycle. However, his December 1888 patent only lasted two yours – Scottish inventor Robert William Thomson had patented the idea in France 41 years earlier.

Dunlop Tyres is the sole supplier of tyres to British Touring Car Championship for 2003 to 2006 and the V8 Supercars Championship from 2002 onward. The company also supplies tyres to the Deutsche Tourenwagen Masters and the American Le Mans Series.

In 1910, the BF Goodrich Company was the first to extend the life of car tyres by adding carbon black to tyres’ rubber compound.

In 1946, Michelin introduced the first radial car tyre.

Car tyres leave their mark. In the US, nearly 50 million pounds of rubber is worn off tyres every week. That’s enough rubber to make 3.25 million new car tyres.

Americans throw away between 240 and 260 million worn car tyres every year. Car tyres make approximately half a million cubic yards of landfill every year in New York State alone.

Not car tyres but truck tyres this time – it takes half a barrel of crude oil to make just one.

In Australia in July 1964, Donald Campbell set a new land speed record and took the car tyre to a new level. His car, the Bluebird CN7, had tyres 8.2 inches (21cm) wide and 52 inches (1.32 metres) high. Each tyre weighed 50 lbs (23 kg) and was filled with nitrogen at a pressure of 100psi. The car reached 403.10 mph.

A top Formula One pit crew can change all four car tyres and refuel in just 3 seconds.

Merityre are a leading UK independent supplier of car tyres. Why not visit their website at www.merityre.co.uk and see where you can buy your next set of tyres.

Tyre Hieroglyphics - What Car Tyres Sidewall Markings Mean

Have you ever noticed that tyres have moulded markings on their sidewalls? You’ll probably have spotted the maker’s name but does the rest mean anything to you? Can you tell what 205/70R14 88 T is all about? Perhaps not yet but understanding these codes could save your life. Why? If they show your tyres aren’t the right ones for your car you can arrange replacements.

We can start by breaking down the example above; the markings denote the tyre size, construction, and load and speed rating. How? Like this…

205 – This is the width of the tyre’s section in millimetres. The section 205 is a little over eight inches wide.

70 – This is the tyre’s aspect ratio, the sidewall’s height expressed as a percentage of its width. Here, the height is 70 per cent of the width. ‘Low profile’ tyres are fashionable so aspect ratio figures go as low as 30. Ultra-low tyres like this give tremendous grip but you pay for it, in a poorer ride quality and very little protection for your wheels against kerbs, potholes and speed bumps.

R – The next letter indicates the tyre’s construction. Here, R means radial.

14 – This next number is also simple. The figure 14 refers to the diameter of wheel the tyre will fit, in inches.

88 – Not so simple but extremely important. This tyre load index is a code for the maximum load capacity of the tyre when driven at its maximum rated speed. The figure 88 denotes a rating of 560 kilograms. Car tyres need to be correctly rated for load.

T - The last letter indicates the tyre’s speed rating. The letter T means the tyre can cope with extended use at a maximum speed of 118 miles per hour. The top speed rating is Z, which appear on tyres for cars capable of maintaining 149mph and above.

There are other tyre sidewall markings but most are for the attention of the tyre fitter. Markings show the tyre complies with EEC, ECE and US regulations. There might be an arrow symbol showing the tyres’ direction of rotation and there’ll be a ‘TWI’ mark indicating where the running surface’s tread wear indicator lies. There will also be a safety warning, perhaps the country of manufacture, whether the tyre is tubed or tubeless, and coloured markers showing the fitter where to fit the tyre in relation to the wheel’s valve.

All these are largely for the fitter’s information but there’s one marking you’re advised to note. The last four digits in the ‘DOT’ code reveal the tyres’ date of manufacture. Four-digit codes began after 2003 so if you see, for example, the code 3 0 0 8, the tyre was made in the 30^th week of 2008. You should never use tyres over 6 years old but a good tyre fitter won’t fit ‘new’ tyres that are beyond their sell-by date.

It’s true that checking your tyre markings could save your life, simply because underrated tyres could fail, especially under high speed/load conditions. The right tyres could save you something else –under-specified car tyres can invalidate your insurance.

For more advice about which car tyre is best for your car then ask our experts at Merityre.co.uk.

Anatomy Class: what a car tyre's made of and how they’re produced

Your car tyres are all that keep you on the road and in dealing with heat, cold, wet and dry conditions and various surfaces, they have a hard life. Knowing what tyres are made of and how they’re built will help you understand how they cope.

Car tyres are built round an inner liner of halobutyl rubber sheet with additives that help keep air inside the tyre. The next part out is the body ply, which consists of three layers, one of rubber, one of reinforcing fabric and a second layer of rubber. Rayon, nylon, polyester or Kevlar have replaced cotton as the reinforcing fabric and it is the tyre’s one or two body plies that give it structural strength while making it flexible.

Externally, the car tyre’s sidewalls make it resistant to abrasion and chemical attack. Sidewall material includes antioxidants and antiozonants to help maintain strength and flexibility. This goes on in and behind the sidewalls on which you can see the tyre maker’s name and the various code digits that the confirm tyre’s size and rating.

The tyre beads lie at the edges of the sidewalls. They are bands of high tensile steel wire, coated with an alloy of copper or brass to prevent corrosion. The beads, inside their rubber casings, are strong points in tyres. They are what holds it firmly to the wheel and help seal in the air. The apex is the section that joins the bead and sidewall. Triangular in section, it is the cushion between the two.

Now for the belt package, the part that lies beneath the tread. This consists of a two rubber layers sandwiching a layer of steel cords. Here’s where ‘radial’ tyres gets their name; the cords run radially in the package. This steelwork gives the tyre the strength to resist dents from road impacts.

Like the sidewalls, the tread is a visible part of a car tyre. The tread compound is as important as the tread pattern. Tyres made of hard compounds wear well, while softer ones grip the road better. ‘Compromise’ is the watchword.

How are car tyres built? This process starts by wrapping the inner liner, body plies, sidewalls and beads around a special drum. The belt package and tread are then added. During this process, the components are ‘spliced’ together, before the ‘green’ (uncured) tyre is blown up and shaped. These tasks are generally automated.

Now comes the curing process. Though spliced, the various parts of the tyre have yet to be bonded together. This involves applying heat in a mould, to speed the chemical reactions between the different materials. During this stage, a rubber bladder, the equivalent of an inner tube, is used to force the tyre into the mould. Unlike an inner tube, the bladder is filled with steam, hot water or an inert gas. Tyre curing is done at very high pressure – about 350 psi – and at around 350 degrees farenheit. A passenger car tyre can be cured in around 15 minutes. Finally, the tyre is run on a mock road surface, to test for imbalance and local inflexibility. All tyres are visually inspected, some are even X-rayed.

So as this shows, there is more to a car tyre than meets the eye. It’s no wonder car tyres are tough enough for the tough job they have.

Merityre are a leading UK independent supplier of car tyres. Why not visit their website at www.merityre.co.uk and see where you can buy your next set of tyres.

For the Sake of Your Car Tyres: Wheel Alignment

Most garages selling car tyres offer a wheel alignment service but not all customers know what this is or what it’s for when they come to buy new tyres. As its name suggests, wheel alignment is to ensure that your car’s wheels are parallel to each other and perpendicular to the ground. Aren’t the wheels like this anyway? They should be but wear and tear, especially that aggravated by speed bumps, can put the wheels out of alignment, as can damage caused by touching a kerb or hitting carriageway debris. Misalignment can cause a braking car to pull to one side or the other, give inaccurate steering and drastically shorten tyre life.

What is involved?

There are usually three factors to be checked and if necessary, adjusted.

The first test is to ensure the wheels are vertical as viewed from the front of the car – this is checking the camber angle.

The second check is slightly more complicated. A car’s front wheels are turned from side to side when you steer. Imagine looking at a front wheel from the side of the car. If you had X-ray vision, you’d see that the steering pivot isn’t vertical but leans back at the top, towards the rear of the car. This is the castor angle, which, if out of adjustment, can cause all manner of strange steering behaviour when you drive.

The third and last check is the tracking. Again looking from the front, the car tyres are usually ‘cross-eyed’, they ‘toe-in’. This is so slight you can’t see it but the setting is important. The tyres are generally set to toe-in so that the when the car is driven, the forces acting on the front wheels and suspension make the front wheels run parallel to one another. If the tyres ‘toe-out’ (think Marty Feldman) through misalignment, or toe-in too much, steering accuracy will suffer and tyre wear will increase. On many cars it’s also possible for the rear wheels to be misaligned.

Should car tyres be worn through misalignment and/or have worn or damaged steering or suspension parts, or even the wrong tyre pressures, correct alignment could be difficult or impossible. The technician will ensure you know about what, if anything, needs adjusting, repairing or replacing.

Man at Work

Wheel alignment used to be achieved with mirrors, weights and string. But such paraphernalia is old hat now; technicians usually use computerised, laser-equipped measuring installations. With these, they can measure and adjust wheel alignment quickly and extremely accurately. So while you enjoy a refreshing cup of tea or visit the shops, your car’s wheels will be aligned with precision, which will extend the life of your car tyres.

What is involved?

How can you keep them this way? Simple – all that’s needed is a little care when you drive. Avoid any debris on the road and watch out for potholes. Take your time over speed pads and straddling speed bumps damages tyres and suspension; drive so that only the wheels on one side of the car go over the bump. Most importantly, when manoeuvring, do not hit kerbs.

Why not drop in to Merityre and get your tyres checked?