Merityre Article Archive

We may not view them for very long but movie star cars live on in our memories. Not all movies featuring memorable motors are car chases wrapped in sub-plots. That said, car tyres aren’t just for these four-wheeled screen idols to sit on. Yes, rubber was burnt in many instances. The tyre-smoking heroes here have one thing in common – they’re all from the ‘States. So let’s take a look across the pond at some US-born petrol-driven thespians.

The 1971 film ‘Vanishing Point’ is a classic car chase wrapped in celluloid. Starring Barry Newman and Cleavon Little (who went on to great things in ‘Blazing Saddles’), Vanishing Point revolves around a fifteen-hour, transcontinental drive from Denver to San Francisco. The star car tyres doing the revolving in the film were fitted to a 1970 Dodge Challenger R/T, the suffix letters referring to ‘road and track’. This 6.2-litre monster, driven by Erich Heuschele, developed the power of 375 gutsy, all-American horses. The car’s F70x14 car tyres put the power onto the tarmac, with the aid of the Challenger’s R/T package. Interestingly, the same model in the same colour popped up in Quentin Tarantino’s 2007 movie ‘Death Proof’. What’s more, the Challenger’s pedigree goes back in time. The black car driven by the baddies in ‘Bullitt’ was a 1968 Dodge Challenger 440 R/T.

More tyre-smoking Detroit iron finished in black starred in 1977′s ‘Smokey and the Bandit’. The motorised matinee idol here wasn’t Burt Reynolds, it was a 1977 Pontiac Trans Am. This car’s history can be traced – it stemmed from a General Motors Design show car created for GM design supremo Bill Mitchell. On this Trans Am, the car tyres were put under pressure in more than the literal sense. The car’s 7.5 litre V8 motor became the last of the muscle car engines. Increasingly stringent emissions regulations in the US finally killed off these big V8 beasts in 1980. The stunt team on ‘Smokey’ pre-empted this, killing off, or at least damaging, all five film cars.

Now for something more unusual, though still in black paint. The next movie star was built using three Model T Ford bodies and a 133-inch hand made chassis. The Munsters Koach was created in 21 days in 1964, at a cost of $18,000; it took 500 hours to make its ornate steel scrollwork alone. Another big V8, by Ford this time, sent the power to the tyres via a four-speed manual gearbox, and the brass radiator and wings were hand formed. The Koach had ten Stromberg carburettors. On an eight cylinder engine? Not really. The visible carburettors were dummies, concealing two functioning four-barrel carbs.

In the Munsters, Grandpa, played by Al Lewis, became more than a little jealous of the Koach. So he acquired ‘Drag-U-La’. This vehicle was notable for its spindly front tyres, mounted on Speedsport English buggy wire wheels. The V8 engine’s 350 horsepower was transmitted to 11 inch-wide Firestone racing slick car tyres, mounted on specially made ten-inch deep Reynolds aluminum Rader drag wheels. Still more characteristic for a ‘vampire’, Drag-U-La’s body shell was a coffin. The original Drag-U-La, one of four built, hangs from the ceiling in Planet Hollywood, Atlantic City, New Jersey.

Who was the talented creator of these last two oddities? The man responsible for putting a lot of tremendously memorable tinseltown tin on tyres. Yes, it was none other than Batmobile creator George Barris.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

The usual seasonal symptoms are back again. In the UK, winter presents a series of tough tests for car tyres. As well as your tyres, it is you who are on test – drivers, rather than cars, generally cause accidents. Here are some salient points about winter driving…

Snow and Ice

A mountain climber’s crampons, the tracks on a Caterpillar tractor, the toothed drive belt on a snowmobile…certain things are made to grip on snow and ice. Since (with some exceptions) you can’t fit such things on your car, you have to cope, using the tyres your car usually wears. There is, however an option. When the temperature drops, your usual tyres will lose flexibility. Winter car tyres are designed to retain their flexibility at lower temperatures, so it makes sense to invest in a set. Motorists are discovering that such car tyres really do offer significantly enhanced grip and control, and using them on a set of  (preferably steel) ‘winter wheels’ will preserve your usual alloy wheels from the ravages of salt and grit.

What are the exceptions? Countries with permafrost can be home to car tyres with studs. In the UK, seriously bad conditions can trigger the use of snow chains. A new item occupies the middle ground. Snow socks are car tyre covers made of a tough, woven material. Easier to fit and quieter than chains, they can be useful when drivers are caught out by unexpected snowfalls. Bear in mind that they will wear out in no time on tarmac.

Rain

When it isn’t quite cold enough to snow, rain and sleet present car tyre challenges of their own. Reduced visibility is a foregone conclusion but don’t forget that wet weather compromises grip. Your car tyres will move surface water but a wet surface remains relatively slippery. Remember to leave more room between you and the vehicle in front, to allow for increased braking distances.

Flooding

Lots of rain can lead to flooding. Standing water can be dangerous. When your car tyres hit it, you’ll feel the steering wheel pulling in response. At worst, your tyres may aquaplane. When the tyres ride on the surface of the water, suspiciously light steering signals radically reduced grip. If you feel this, lift off the throttle and slow down until the grip returns.

If you encounter a flood, remember that negotiating it requires care. Keep to the crown of the road, where the water will be shallower, and look out for the white line. This will help you gauge the depth of the water. While you can trust your tyres, remember that your engine, if it sucks in water, will be wrecked. Keep the engine revs up to help stop the exhaust inhaling water. However, if you are in any doubt whatsoever about the depth of the water, use another route.

Fog

In thick fog, you’re bound to suffer loss of visibility. Your car tyres won’t suddenly offer greater grip just because you notice that you’re hurtling towards the back of stationary truck. So drive as fast as you can see, and no faster. Remember to use your windscreen wipers and washers often in fog; your screen can collect water and grime surprisingly quickly, further reducing visibility.

In winter, the watchword is caution. Even on winter car tyres, grip will be compromised to some extent by bad weather. Should the visibility and grip be truly awful, simply put your feet up by the fire and live to drive another day.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Car tyres don’t generally ask too much of you. However, neglecting them can prove expensive and, in some circumstances, dangerous. These ten tips will enhance car tyre life, reduce your spending and perhaps save your life.

1. The wrong car tyre pressure is costly. Running on overinflated tyres accelerates wear and reduces both grip and ride comfort. Underinflated tyres also wear more quickly, and can worsen fuel economy by as much as ten percent. Check your tyre pressures regularly.

2. Cuts in car tyres are obvious. Lumps or bulges may be less so but they tend to indicate damage inside the car tyre’s carcass. Check for any such damage while correcting tyre pressures. If in any doubt, avoid the risk of a blowout by having a tyre specialist examine the damage.

3. A spare wheel with a flat tyre is worse than useless. Check the spare tyre pressure regularly, unless you have run flat tyres or an onboard tyre pump and repair kit. Remember that space saver spare tyres generally have speed and distance restrictions.

4. If, at car tyre checking time, you find a stone embedded in a tyre tread, you can lever it out before it causes damage. However, if you find a nail in a tyre, leave it alone. The nail will be temporarily keeping the air in – have a tyre specialist take a look. He may be able to repair the tyre.

5. While using the tyre inflator at a garage, or a tyre pump at home, look after the tyre valve dust caps. They keep dirt and grit away from the delicate valves, and are a line of defence against tyre pressure loss. Always put them back carefully.

6. Potholes can damage more than your car tyres. Hit a large one hard enough and you could be facing a bill for the repair or replacement of one or more wheels. Should you be unlucky enough to encounter a big pothole and suspect damage has occurred, stop and examine the affected wheel(s) and tyre(s).

7. Never straddle a speed bump. Instead, let the wheels on one side of your car pass over the bump. This will prevent damage to your car’s tyres, steering and suspension. When negotiating speed bumps and road-width speed pads, slow down or face the cost of repairs.

8. When you’re manoeuvering, curb your enthusiasm so you don’t kerb your car tyres. Kerb impacts can wreck not only tyres, they can scratch, chip and even dent your car’s wheels. Steering misalignment can also result from kerbing.

9. Keep your car in a garage, if you can. Car tyres suffer from prolonged exposure to ultra violet light. This leads to cracking and crazing of the car tyre sidewalls’ structure.

10. When the time to buy replacement tyres rolls around, think about replacing all four. Should this be too costly, always have new tyres fitted in pairs. It’s accepted that the new tyres should be fitted to the rear wheels.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Here’s a sobering thought. Summer or winter, rain or shine, all that lies between you and a short, damaging trip into the scenery is the equivalent of the area of four shoe soles. Yes, every car tyre has a ‘contact patch’ the amount of its treaded area that touches the road. This area is only the size of an adult’s footprint.

Let’s say your car weighs one tonne. Nobody weighs half a tonne and the soles of his or her shoes do a pretty good job, expect perhaps on ice or snow. Translated into car tyre terms, the four-sole area has to do much, much more. It’s unlikely, for example, that a road car could generate a cornering force of 1g. Under heavy braking, it’s quite possible for such a force to be generated. Moreover, the forces generated during acceleration and cornering can be very high. Your car tyres and their contact patches do more than a ‘pretty good job’. You don’t usually expect your shoes to keep you from slipping in adverse conditions, such as on gritty or diesel-soaked tarmac in extremes of temperature. Your car tyres do this on a regular basis.

Legally, each of your car tyres must have a minimum of 1.6 millimetres of tread across ¾ of the width of the tyre’s running surface. Not meeting this requirement can get you three penalty points on your licence, as well as a £2,500 fine…per tyre. So, four balding car tyres equals a lost licence and fines of up to £10,000.

In this context, the law could be called an ass. Why? Because just 1.6 millimetres of tread on a car tyre is cutting things fine when it comes to grip. The Royal Society for the Prevention of Accidents (RoSpa) put this to the test. They tried some emergency stops in a typical car on some typical surfaces. On smooth concrete, as some motorway stretches have, the car’s barely legal tyres took a distance of 46.6 percent more to stop than an equivalent car with good tyres. Similarly, on hot rolled asphalt, the worn tyres needed 36.8 percent more distance to bring the car to a halt. There’s no need to ask why RoSpa recommends a minimum tread depth of 3 millimetres.

This isn’t the only scenario where worn car tyres will struggle. Tyres are designed to act like water pumps in wet conditions, they can clear surface water from their contact patches. When this fails to happen properly, the tyre will ride on a thin film of water. If this happens, you’d feel the steering lighten, which is an indicator of what’s actually going on. When a car tyre is unable to cut through road water fast enough, it will aquaplane. Aquaplaning equals significantly reduced grip, as you might find out when you attempt to steer or brake.

Whilst it may seem to make sense to get the very most out of the treads on your car tyres, there is such a thing as false economy. Your car tyres have wear indicators, moulded into the treads. Take a look at them and, if the treads no longer stand proud of the tread wear indicators, it’s new tyre time. Running your tyres down to the legal minimum could cost you far more than you think.

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Merityre.co.uk are one of the  leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Wheel alignment? Surely your car’s wheels are in line all the time? In fact, they aren’t necessarily. Speed bumps, kerbing, speed pads and general wear and tear on a car’s suspension and steering can put the wheels out of alignment. Misalignment may be felt as pulling to one side or another, and/or strange steering. In the longer term, your car tyres will suffer – bad wheel alignment can radically reduce tyre life.

So, how do you fix poor wheel alignment, thus making your car steer and brake better, as well as achieving maximum car tyre life? The good news is that car manufacturers provide a means of adjusting wheel alignment. The not so bad news is that you can’t correct poor alignment yourself.

Cue a visit to your local friendly tyre man. Good tyre bays (and garages) have the equipment to check and adjust wheel alignment. All you have to do is watch (or not, depending on your preference) and pay for the work. Then, drive away secure in the knowledge that your car is shipshape in the wheel alignment department.

What happens in a wheel alignment session? Generally, three things are checked, and adjusted as necessary. The first check establishes that the car tyres are vertical, as viewed from the front or rear. Sometimes, the tyres may not be truly vertical. Some cars’ tyres sit at a slight angle from the perpendicular. This is the camber angle, which can be adjusted to meet the car maker’s specification.

The second check involves another angle, the castor angle. Does your car run on castors? Technically, yes, the castor angle permits the wheels and tyres to return to straight ahead when the car is rolling with no steering input.  As you know, your front wheels turn from side to side in response to your turning the steering wheel. No matter how the wheels and tyres pivot, a line drawn through the centre of the axis on which they pivot won’t be vertical. The line has to lean backwards slightly and if it doesn’t, the steering will feel very odd. Again, this can be cured by adjustment.

The last check is on a figure called the ‘toe’. All car suspension has a small degree of flexibility built into it. So, if the car tyres are parallel at rest, the drag between them and the road as the car moves would cause this flexibility to allow the wheels to splay very slightly. You wouldn’t see this but your tyres would soon tell you all about it, by wearing out the inner edges of their treads. So, the wheels are usually set to ‘toe-in’, so they run parallel. If the tyres toe out, if the toe-in is too much or if the toe angle varies from side to side, the car tyres will wear out prematurely. Curing this is again a matter of adjustment.

Wheel alignment used to be checked with a special gauge that used a mirror and lens system. Nowadays, it’s common for car tyre bays and garages to measure the angles involved using laser equipment. Yes, accurate measurement is necessary. In some instances, worn suspension or steering components mean that a problem can’t be adjusted away. Then, the tyre man in question will tell you what needs repairing or replacing for accurate alignment to be achieved.  It’s also the case, especially on a car with independent rear suspension, for the rear wheels and tyres to be misaligned. Once again, adjustment is usually possible.

Is it possible to stop your car’s wheels becoming misaligned and making the tyres suffer? In a word, yes. Don’t kerb your car tyres. Avoid potholes and traverse speed pads carefully. Above all, always negotiate speed bumps with the tyres on one side of your car. Straddling speed bumps is a major cause of both wheel misalignment and tyre carcass damage. You have been warned!

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

‘There are lies, damned lies and statistics.’ Mark Twain claimed Benjamin Disraeli said this in the 19^th Century. True, some say that statistics can be misleading but they can also be sobering, to say the least.  Take, for example, this figure, released in September by the Department for Transport. Apparently, illegal, defective and underinflated car tyres caused over 1,210 road casualties in Great Britain during 2010. Over the last five years, 164 motorists have died as a result of having defective car tyres, 18 of those deaths occurring in 2010, according to the Road Casualties in Great Britain report.

What can be done about this? Well, October is Tyre Safety Month. Not for profit organisation TyreSafe was established in 2006 and is now one of the UK’s leading tyre safety organisations. As its chairman Stuart Jackson says, “The latest figures are truly shocking and emphasise why we need ongoing action, education and awareness about tyre safety issues.”

TyreSafe is working hard to ensure that we are informed about the importance of looking after ourselves and the safety of others by looking after our car tyres. As part of Tyre Safety Month, drivers will be given a free tyre safety check. Where? Hundreds of tyre dealers and garages are taking part, so try your local ones.

There are also a number of online resources, to show you how to carry out critical car tyre safety checks quickly and easily. An enlightening online video, of a car being driven on ice, demonstrates the benefits of winter tyres.

Stuart Jackson continues, “If all drivers took just a few minutes every month to check their tyre pressures, condition and tread depth, we could help prevent this needless injury and loss of life. Our website contains some really simple guides to help drivers understand what to look for.”

Tyre Safety Month is as much about education as awareness. The abovementioned website has material that will leave you fully informed about your car tyres and safety. You can learn about checking your tyres’ tread depth and ensuring they contain the correct tyre pressure. There are also TyreSafe’s ‘Magnificent 7 Car Tyre Safety Tips’.

As we all know, the tail end of the summer season heralds the onset of poorer weather. We should also bear in mind that the need for car tyre safety monitoring will continue ad infinitum…it won’t go away when November blusters its way in. In the short term, you can take a look at the TyreSafe web site. In the longer term, you may want to consider investing in a set of winter tyres. Or you could reflect on the wisdom of looking after the tyres you already have, keeping them in prime condition and being aware of the need to replace then as and when necessary.

The bottom line is this. As has been said time and time again, your car tyres are all that are ultimately keeping you on the road. Assuming you have no desire to become a statistic, neglect them at your peril.  Why not take a look at keeping your tyres safe– it might just be a life-saving bit of browsing.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Formula One teams spend vast amounts on research and development. They spend on aerodynamics, on construction with composite materials, and on wringing the maximum amount of power from their engines. We must, however, remember that in Formula One, tyres remain the largest single performance variable.

So, car tyres are car tyres, right? Not quite; road car and racing car tyres are distant relatives at best. Road car tyres are made to last, typically for a life of 16,000 kilometres or more. Formula One car tyres are made to last 200 kilometres at most, but they are made to be both light and strong. Their internal nylon and polyester structure, with its complicated weave pattern, is designed to handle much greater forces than a road car tyre faces. Let’s put it this way, no road car is likely to generate a tonne of downforce, or 5g of longitudinal load…or 4g lateral loadings.

F1 car tyres’ soft rubber mix is there to offer maximum grip, at the cost of a limited life. The tyres wear very quickly. They also become very hot but this is meant to happen – cold race tyres offer little grip. By way of example, the dry grooved tyres used until recently were designed to run at between 90 and 100 degrees Centigrade. Look carefully at the TV footage and you’ll see the cars’ tyres, pre-race, clad in special coverings, which are electrically heated. The need for heat explains why Formula One cars can be seen weaving from side to side on the way to the starting grid. The drivers are perfectly sober and they aren’t playing – they’re just warming their tyres.

Slick tyres, those with no tread at all, offer maximum grip. However, it was decided in 1998 that slicks be outlawed. Grooved tyres were made de rigeur, to help improve F1 racing as a spectator sport by reducing cornering speeds. This made life difficult for the tyre makers. The rules specified that all tyres had to have four continuous grooves at least 2.5 millimetres deep, spaced 50 millimetres apart. So, tyre manufacturers had to adopt harder rubber compounds, to maintain tyre integrity. By the 2009 season, slick tyres came back. The FIA, Formula One’s governing body, decided to use limits on F1 car aerodynamics as a means of keeping cornering speeds down.

How ‘soft’ or ‘hard’ the rubber compounds in F1 car tyres are, is varied by race, according to each track’s characteristics. For each Grand Prix race weekend, teams choose from two different compounds, and every driver must use both during the race. What makes the difference in the hardness of the different specifications? A change in the proportions of ingredients added to the rubber mix. Of these ingredients, the three main ones are sulphur, carbon and oil. In general, more oil equals a softer tyre compound.

Formula One car tyres are obviously run at the appropriate pressures. However, air pressure isn’t quite the right term. F1 car tyres are inflated with more nitrogen gas than air. This gas and air mixture is less susceptible to pressure loss and minimises the pressure differences that come about through temperature changes.

As will have become clear by now, there are huge differences between road car tyres and Formula One car tyres. They may share basic characteristics but the common denominators between them are certainly low on the scale.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Many people take their car tyres for granted, but there’s far more to them than meets the eye. Knowing how they are made will illustrate this point.

How is a car tyre made? Production starts with a halobutyl rubber sheet that has special air-retaining additives. This sheet forms the tyre’s inner liner. A three-layer body ply comes next, in which a central layer of reinforcing fabric is sandwiched between two layers of rubber. Cotton used to be the material of choice for the reinforcing fabric but this has been replaced with Nylon, Rayon, polyester or even Kevlar. The body ply’s role is to give the tyre strength and flexibility; two such plies may be used in a tyre.

The acceptable faces of the tyre, the sidewalls, include antiozonants and antioxidants to enhance their life. The sidewalls can resist chemical attack and abrasion, and the tyre’s ratings and size codes are moulded into them.

Of course, the tyre’s sidewalls need to form a seal on the wheel rim. Bands of high tensile steel wire, copper or brass coated for corrosion resistance, form the beads on the inner diameter of the sidewalls. The triangular rubber section that joins the beads to the sidewalls is called the apex. The bead structure is what forms an airtight seal with the wheel rim.

Now for the tread and its underlying structure. The belt package is the part of the tyre that sits inside the tread. It’s made up of two layers of rubber that enclose a layer of steel cords. These cords run radially in the belt package, hence the term ‘radial tyres’.  The belt package is a major player in the tyre’s strength. The tread pattern is visible but the rubber compound used to make it is just as important. The choice of compound is a matter of a selecting a balance, between hardness (wear) and (grip). Think ‘compromise’.

These are the parts of a tyre and they must obviously be assembled and made into a tough, resilient structure. This procedure begins with wrapping the inner liner, body ply(s), sidewalls and beads around a special drum. Then, the belt package and tread are added, and the various elements are spliced together. At this stage the tyre is yet to be cured, and is known as a ‘green’ tyre. In this state, it is inflated and shaped.

Curing comes next, to bond the various parts of the tyre into a coherent whole. A rubber bladder is inflated inside the tyre, forcing it into a mould. Hot water, steam or an inert gas is used to inflate this bladder, and the curing process involves a great deal of heat and pressure…350 degrees Fahrenheit and 350 pounds per square inch to be precise. The curing process takes about 15 minutes.

The final stage is to test the cured tyre on a mock road surface, to seek out localized inflexibility and significant imbalances. Every tyre is given a visual inspection and sometimes, an X-ray inspection too.

So, car tyres are built tough to be tough, which they must be to take on the tough job they do. As they are all that keep your car on the road, it’s reassuring to know how much effort and care go into making them.

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Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.