On petrol cars, a catalytic convertor has become a standard part of the car exhaust. Catalytic convertors – ‘cats’ for short – originated in America. Like many other items, cats soon went transatlantic and later made their way into European legislation. Unsurprisingly, they wound up in the UK.
Let’s begin with the nuts and bolts of the matter. In chemistry, a ‘catalyst’ is a substance that causes or accelerates a chemical reaction without itself being affected. Fair enough but what has this to do with car exhausts? Still talking at nuts-and-bolts level, a catalytic converter is a device that uses a catalyst to convert three harmful compounds in car exhaust gases into harmless chemicals.
Again, fair enough but what are these three compounds that are so harmful? They are to be found in the exhaust gas of any petrol car and consist of…
Hydrocarbons (incompletely burnt fuel)
Carbon Monoxide (formed when petrol burns)
Nitrogen Oxides (made by combustion heat making atmospheric nitrogen combine with oxygen.)
So, just how scary are these components in car exhaust gases? Carbon Monoxide, a.k.a. CO, is the nastiest one, being poisonous to any organism that breathes air. Nitrogen oxides (NO2) lead to the formation of both smog and acid rain. Relatively innocent Hydrocarbons (HC) just produce smog but are particulate matter, which makes matters worse.
A catalytic convertor, looking rather like a silencer, forms part of a car exhaust system. The catalyst used is liable to consist of precious metals such as rhodium, platinum and palladium. These coat a ceramic honeycomb or ceramic beads inside the ‘cat’. Carbon monoxide is converted into the less harmful carbon dioxide (CO2) and hydrocarbons are converted into carbon dioxide (CO2) and water (H2O). As for the nitrogen oxides, these are converted back into nitrogen and oxygen.
Though they don’t have moving parts, ‘cats’ can suffer malfunctions. If the catalytic convertor in a car exhaust stops working, you won’t necessarily know about this until your next MOT test. A failed cat may just be worn out or its substrate (the metal-coated pellets or ceramic honeycomb inside) may have broken down. Your car may run perfectly well – it just won’t be able to pass the emissions test part of an MOT.
Often, diagnosing what’s awry with the cat in a car exhaust is tricky. If something has gone wrong with the car’s fuel system and it allows raw fuel into the cat, the unit will run red hot. This is usually pretty easy to detect, which is just as well, as the substrate can shatter at such temperatures. Fouled sparking plugs, incorrect ignition timing and failure of the engine’s air pump and/or check valve can also cause overfuelling.
Should the cat’s innards go into meltdown, or shatter through thermal shock or overheating, the result will mimic a blocked car exhaust. A sluggish throttle response is the major clue. Modern electronics mean that a fault light will flash to verify there’s a problem but detecting exactly what the problem is likely to involve diagnostics – on a laptop computer. In any event, should the problem lie within the ‘cat’, a good tyre and exhaust bay will be able to offer you a replacement unit.
Article Resource
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.
Tuesday, 10 July 2012
Tyres On Trial
Suppose you were regularly wearing out a set of tyres on your Mini Cooper in three miles. You’d certainly be doing something very wrong, wouldn’t you? However, this is the usual car tyre mileage on one of The Russ Swift Mini Display Team’s Coopers and Russ is doing something very right – in the eyes of his sponsors and spectators, that is.
The Team, part of Russ Swift Driving Services, was formed in 1981. Current British Autotest champion and England Autotest Team Captain Russ had often been asked to demonstrate his incredible, tyre-testing car control skills. He realised a gap existed in the marketplace and contrived to fill it.
In 1987, an advertising agency saw a video of Russ at work. This led to the renowned Montego “Car Park” commercial. Though this was aired in the UK for just six weeks, the squeal of tortured car tyres was heard when the performance was featured at the Cannes Film Festival. It was also voted by American judges as the world’s most imaginative car commercial.
Where did Russ go from there? A long, long way. Eight thousand tyre-munching displays in more than 50 countries and three Guinness world records (Parallel parking in the tightest space, J Turn in the tightest space and the fastest donuts) form just a small part of his CV.
Russ and Minis go back a long way too, starting with four British Autotest Championship wins and an International Rally win in Sweden in the early eighties, in a Cooper S. More recently, Russ was involved in promoting the remake of ‘The Italian Job’, performing at premieres in London and New York. He fulfils an advisory role with many police, military, royal and diplomatic drivers, also working closely with RoSPA, the IAM and various other road safety bodies to promote safe driving. A versatile player on the car world’s stage, Russ is committed to ensuring that it is only car tyres that suffer!
The tools of Russ’s trade are largely unmodified cars. Russ uses a Mini Cooper S, standard apart from a “piece of tape on the handbrake button”. Another Mini Cooper has one other mod – a locked differential – to allow for driving on two wheels (this is the one that gets 3 miles per set of tyres – should that be per pair?). Typically, a further Mini Cooper is used (all these are BMW MINIs). Often, an MR RS Mitsubishi Evolution undertakes power slides and donuts.
A typical show features reverse spins at 40mph, parking in a slot between two cars parked side by side, using only the handbrake. Similarly, ‘parallel parking’ involves a handbrake turn into the gap between two cars parked as though at the kerbside. Then there is a ‘dance routine’ to music, involving two cars and a ramp. This last – the ramp – is used for the business of getting the locked-diff Cooper up on two tyres. The show features music and commentary – and audience participation is encouraged. The tyres may be red hot but the invited passengers have been known to end up on the pale side!
Find out more – and see pictures and videos – at www.russswift.co.uk.
Article Resource
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 Team, part of Russ Swift Driving Services, was formed in 1981. Current British Autotest champion and England Autotest Team Captain Russ had often been asked to demonstrate his incredible, tyre-testing car control skills. He realised a gap existed in the marketplace and contrived to fill it.
In 1987, an advertising agency saw a video of Russ at work. This led to the renowned Montego “Car Park” commercial. Though this was aired in the UK for just six weeks, the squeal of tortured car tyres was heard when the performance was featured at the Cannes Film Festival. It was also voted by American judges as the world’s most imaginative car commercial.
Where did Russ go from there? A long, long way. Eight thousand tyre-munching displays in more than 50 countries and three Guinness world records (Parallel parking in the tightest space, J Turn in the tightest space and the fastest donuts) form just a small part of his CV.
Russ and Minis go back a long way too, starting with four British Autotest Championship wins and an International Rally win in Sweden in the early eighties, in a Cooper S. More recently, Russ was involved in promoting the remake of ‘The Italian Job’, performing at premieres in London and New York. He fulfils an advisory role with many police, military, royal and diplomatic drivers, also working closely with RoSPA, the IAM and various other road safety bodies to promote safe driving. A versatile player on the car world’s stage, Russ is committed to ensuring that it is only car tyres that suffer!
The tools of Russ’s trade are largely unmodified cars. Russ uses a Mini Cooper S, standard apart from a “piece of tape on the handbrake button”. Another Mini Cooper has one other mod – a locked differential – to allow for driving on two wheels (this is the one that gets 3 miles per set of tyres – should that be per pair?). Typically, a further Mini Cooper is used (all these are BMW MINIs). Often, an MR RS Mitsubishi Evolution undertakes power slides and donuts.
A typical show features reverse spins at 40mph, parking in a slot between two cars parked side by side, using only the handbrake. Similarly, ‘parallel parking’ involves a handbrake turn into the gap between two cars parked as though at the kerbside. Then there is a ‘dance routine’ to music, involving two cars and a ramp. This last – the ramp – is used for the business of getting the locked-diff Cooper up on two tyres. The show features music and commentary – and audience participation is encouraged. The tyres may be red hot but the invited passengers have been known to end up on the pale side!
Find out more – and see pictures and videos – at www.russswift.co.uk.
Article Resource
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.
Monday, 21 May 2012
Buyer Beware: How To Buy A Used Car
For many people, a car is the second most expensive purchase they make. Buying the right car can be easy but it's just as easy to encounter expensive pitfalls, especially when buying used. You need to check on everything, from the car tyres upwards and here are some pointers to help you.
Start by making sure you are looking at the right kind of car for your needs. No matter how much you may want to, you won't fit a family of four in a two-seater sports car. Most people don't make such an obvious error but many buy a car that's too big for their garage, too thirsty for their wallet or too expensive to maintain. All cars have tyres, not all have the ability to be run on a shoestring – and you'll always lose if you have to sell.
Lets assume you've found a car. What next? You have to be certain that the car matches the claims made about it. Checking the VIN (Vehicle Identification Number) is a primary requirement. Does it match the number in the V5 document? If it doesn't or isn't clearly stamped, without any evidence of tampering, the car could be stolen, a 'ringer', or the result of two write-offs welded together.
If the VIN is good, does the history add up? We're talking paperwork here, as well as the state of the car itself. Good car tyres, not to mention shiny paintwork and a ludicrously low mileage are of little value if the mileage figures in the previous MOT certificates don't tally. No MOT certificates? This is your cue to walk away.
Much the same goes for service history, which usually has a record of miles covered in it. If the car has in fact been serviced as it should have been, preferably by an approved dealership, which has entered the details into the service record, the car's beginning to look like a good buy. If every last invoice for what has been spent is present and correct, so much the better. This may include receipts for new tyres, an exhaust, a battery and any accessories.
If buying from a car dealer, a genuine HPI certificate must be provided by law. If buying from a private individual, you can arrange to have an HPI inspection. An HPI check validates the car's history and will reveal any shady elements in its past. Remember that, if buying privately, you will buy a car 'as seen'. This means that you can set tyres to tarmac quite happily but if the engine grenades on the way home, it's your problem. There is no recourse in a private sale.
When looking at the car, be very, very critical indeed. If it has been repaired and the repairs have been professionally done, that's fine. If you see badly-matching paint, poor panel gaps, scuffed tyres and ripply surfaces, the car has been badly repaired. Under the bonnet, look out for oil leaks, corrosion, fluid stains and amateur fixes. Pull out the dipstick and look at the oil. Is it black and treacly? Look elsewhere.
Car tyres can be excellent tell tales, as can the wheels that carry them. Uneven tyre wear suggests suspension misalignment at best, damage at worst. Tyres with 3 millimetres or less of tread need replacing, which won't cost the seller a penny. The same goes for cracked tyres or ones with lumps or bulges. Alloy wheels that have been badly kerbed will show significant damage, and say a lot about how the car has been driven.
Finally, remember these golden rules. One: you can always find a rival example of the car you're examining. Two: it’s a buyer’s market; you can always walk away. Three: always buy with your head, rather than your heart!
Article Resource
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.
Start by making sure you are looking at the right kind of car for your needs. No matter how much you may want to, you won't fit a family of four in a two-seater sports car. Most people don't make such an obvious error but many buy a car that's too big for their garage, too thirsty for their wallet or too expensive to maintain. All cars have tyres, not all have the ability to be run on a shoestring – and you'll always lose if you have to sell.
Lets assume you've found a car. What next? You have to be certain that the car matches the claims made about it. Checking the VIN (Vehicle Identification Number) is a primary requirement. Does it match the number in the V5 document? If it doesn't or isn't clearly stamped, without any evidence of tampering, the car could be stolen, a 'ringer', or the result of two write-offs welded together.
If the VIN is good, does the history add up? We're talking paperwork here, as well as the state of the car itself. Good car tyres, not to mention shiny paintwork and a ludicrously low mileage are of little value if the mileage figures in the previous MOT certificates don't tally. No MOT certificates? This is your cue to walk away.
Much the same goes for service history, which usually has a record of miles covered in it. If the car has in fact been serviced as it should have been, preferably by an approved dealership, which has entered the details into the service record, the car's beginning to look like a good buy. If every last invoice for what has been spent is present and correct, so much the better. This may include receipts for new tyres, an exhaust, a battery and any accessories.
If buying from a car dealer, a genuine HPI certificate must be provided by law. If buying from a private individual, you can arrange to have an HPI inspection. An HPI check validates the car's history and will reveal any shady elements in its past. Remember that, if buying privately, you will buy a car 'as seen'. This means that you can set tyres to tarmac quite happily but if the engine grenades on the way home, it's your problem. There is no recourse in a private sale.
When looking at the car, be very, very critical indeed. If it has been repaired and the repairs have been professionally done, that's fine. If you see badly-matching paint, poor panel gaps, scuffed tyres and ripply surfaces, the car has been badly repaired. Under the bonnet, look out for oil leaks, corrosion, fluid stains and amateur fixes. Pull out the dipstick and look at the oil. Is it black and treacly? Look elsewhere.
Car tyres can be excellent tell tales, as can the wheels that carry them. Uneven tyre wear suggests suspension misalignment at best, damage at worst. Tyres with 3 millimetres or less of tread need replacing, which won't cost the seller a penny. The same goes for cracked tyres or ones with lumps or bulges. Alloy wheels that have been badly kerbed will show significant damage, and say a lot about how the car has been driven.
Finally, remember these golden rules. One: you can always find a rival example of the car you're examining. Two: it’s a buyer’s market; you can always walk away. Three: always buy with your head, rather than your heart!
Article Resource
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.
What Are Car Tyres Made Of?
We're told, not necessarily reliably, what little girls and little boys are made of. Happily, we can learn with accuracy what car tyres are made of, and it's reassuring to know that the flexible friends that let our cars be steered and stopped unfailingly are so well constructed.
The heart of a car tyre is an inner liner made of halobutyl rubber. This includes additives that promote air retention. The inner liner is clad in a three-layer body ply, consisting of a layer of Rayon, Nylon, Polyester or Kevlar sandwiched between two layers of rubber. Car tyres may have one or two body plies, giving structural strength and flexibility.
We now move on to visible structures in our car tyre. Using materials that include antioxidants and antiozonants lets car tyre sidewalls resist abrasion and chemical attack, while promoting flexibility and strength.
The inner edges of the sidewalls are the car tyre's beads. Made of corrosion-resistant copper or brass-coated high tensile steel wire moulded into rubber casings, the beads are a strong point, holding the car tyre to the wheel and keeping air sealed inside. The triangular-section area joining the bead and the sidewall is the apex, the cushion between the two.
Back under the skin of the car tyre, beneath the tread, lies the belt package. Two layers of rubber sandwich a layer of steel cords. This package is what allows the car tyre to handle road impacts, from potholes, stones and so on. Usually the cords run radially within the belt package, hence the name 'radial tyre'. The visible tread and the layers beneath it are made of rubber compounds with a specific degree of hardness. Harder compounds wear well, softer compounds offer better grip; a compromise between the two is usually offered.
Now we know what car tyres are made of, how do we go about building one? In short, we don't, unless we happen to own a car tyre factory. In such a premises, a tyre's inner liner, body plies, sidewalls and beads are first assembled around a special drum. After the belt package and tread are added, the components are spliced together before the tyre is automatically inflated and shaped. At this stage, the tyre is uncured, or 'green'.
In this green form, the car tyre's parts are yet to be bonded together, in a curing process. A rubber bladder, inflated inside the car tyre with hot water, steam or an inert gas, forces it into a mould. The 350-degrees Fahrenheit temperature and 350psi pressure used speed up chemical reactions in the car tyre carcass, and the curing process takes about 15 minutes.
The cured car tyre is run on a mock tarmac surface, to highlight any localized inflexibility and/or unbalanced sections. While all tyres are visually inspected, a random sample of tyres is also X-rayed.
Heavy-duty equipment and extremes of pressure and temperature are used make a car tyre. It's comforting to know that these things combine to produce a tough, long lasting result.
Article Resource
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 heart of a car tyre is an inner liner made of halobutyl rubber. This includes additives that promote air retention. The inner liner is clad in a three-layer body ply, consisting of a layer of Rayon, Nylon, Polyester or Kevlar sandwiched between two layers of rubber. Car tyres may have one or two body plies, giving structural strength and flexibility.
We now move on to visible structures in our car tyre. Using materials that include antioxidants and antiozonants lets car tyre sidewalls resist abrasion and chemical attack, while promoting flexibility and strength.
The inner edges of the sidewalls are the car tyre's beads. Made of corrosion-resistant copper or brass-coated high tensile steel wire moulded into rubber casings, the beads are a strong point, holding the car tyre to the wheel and keeping air sealed inside. The triangular-section area joining the bead and the sidewall is the apex, the cushion between the two.
Back under the skin of the car tyre, beneath the tread, lies the belt package. Two layers of rubber sandwich a layer of steel cords. This package is what allows the car tyre to handle road impacts, from potholes, stones and so on. Usually the cords run radially within the belt package, hence the name 'radial tyre'. The visible tread and the layers beneath it are made of rubber compounds with a specific degree of hardness. Harder compounds wear well, softer compounds offer better grip; a compromise between the two is usually offered.
Now we know what car tyres are made of, how do we go about building one? In short, we don't, unless we happen to own a car tyre factory. In such a premises, a tyre's inner liner, body plies, sidewalls and beads are first assembled around a special drum. After the belt package and tread are added, the components are spliced together before the tyre is automatically inflated and shaped. At this stage, the tyre is uncured, or 'green'.
In this green form, the car tyre's parts are yet to be bonded together, in a curing process. A rubber bladder, inflated inside the car tyre with hot water, steam or an inert gas, forces it into a mould. The 350-degrees Fahrenheit temperature and 350psi pressure used speed up chemical reactions in the car tyre carcass, and the curing process takes about 15 minutes.
The cured car tyre is run on a mock tarmac surface, to highlight any localized inflexibility and/or unbalanced sections. While all tyres are visually inspected, a random sample of tyres is also X-rayed.
Heavy-duty equipment and extremes of pressure and temperature are used make a car tyre. It's comforting to know that these things combine to produce a tough, long lasting result.
Article Resource
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.
Monday, 23 April 2012
Extreme Tyres. Car Tyres And More, Small And Large
Sometimes, size is all that matters. It's important when choosing car tyres to select ones that are the right size. However, if you think the 205/45 x 17 tyres on your Mini Cooper S are rather special, stand by to be amazed, and not a little outclassed.
In this instance, 205 millimetres equates to 8.07 inches. These car tyres may look wide on a Cooper S but in reality, they aren't much to write home about. The world's widest car tyre, on the other hand, is worth describing in a letter. The Pirelli P Zero Nero 405/25 ZR 24 is an asymmetric car tyre aimed at 'tuners and the most demanding sports performance drivers'. With a 25% aspect ratio, as the numbers say, this car tyre is bound to look wide. With a width of nearly sixteen inches, it is wide – extremely wide. In fact, the widest car tyre on Pirelli's website is a mere 315 section item, which equates to a comparatively paltry 12.4 inches. That said, the web reports a Chevrolet Corvette special sitting on 405-section tyres, on 24 x 15-inch wheels…and there are pictures to prove it.
To go still bigger as regards tyres, we must move out of the realm of car tyres. Bridgestone used to hold the record for making the world's largest production tyre, with its 59/80R63 V-Steel E-Lug S tyre. Fitted to earthmovers such as the Caterpillar 797B and 797F, these tyres stand 4.02 metres high – that's a little under thirteen and a quarter feet. Each earthmover wears six of these tyres.
Feeling your car tyres are a little underwhelming sizewise? There's more to come. The 63-inch OTR (Off-The-Road) tyres made by Titan are nearly fourteen feet tall and weigh a staggering 12,500 pounds apiece. Each tyre has a nominal load rating of a whopping 101 tonnes. Just don't expect your trusty tyre fitter to stock these 57.9 inch-wide Titan 59/80R63 tyres. Their size and their 5.66 tonne weight means the tyre racks probably won't cope.
Now that you're feeling distinctly ill-equipped with your pathetic little car tyres, the balance can be redressed with the aid of the 'Wind-Up'. This, the world's smallest road legal car, was built by British inventor Perry Watkins. Being a tiny car, the Wind-Up has tiny car tyres, which we'll come to in a moment.
Let's first see the vital statistics that demand such tiny car tyres. The Wind-Up is 41 inches tall, 51 inches long and 26 inches wide. Its Shanghai Shenke quad bike chassis is powered by a 150cc engine with continuously variable transmission. This gives the Wind-Up a top speed of 40mph, and a frugal thirst – it takes 70 miles to sip a gallon of fuel.
The Wind-Up's tyres come from small motorbikes. At the rear, it wears the wheels and tyres from a Honda Monkey Bike, the tyres being dinky 3.5 x 8-inch items. At the front, the Wind-Up rides on tyres from a 1939 Brockhouse Corgi paratrooper’s mini motorcycle, also 8-inch items.
Should you encounter a set of the miniscule car tyres that support the Wind-Up, there may be something more than a little familiar about the vehicle. Its 31.4 cubic foot body was sourced from a coin-operated ride favoured by little kids. Yes, Postman Pat's van got a new lease of life, courtesy of Perry Watkins.
Article Resource
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.
In this instance, 205 millimetres equates to 8.07 inches. These car tyres may look wide on a Cooper S but in reality, they aren't much to write home about. The world's widest car tyre, on the other hand, is worth describing in a letter. The Pirelli P Zero Nero 405/25 ZR 24 is an asymmetric car tyre aimed at 'tuners and the most demanding sports performance drivers'. With a 25% aspect ratio, as the numbers say, this car tyre is bound to look wide. With a width of nearly sixteen inches, it is wide – extremely wide. In fact, the widest car tyre on Pirelli's website is a mere 315 section item, which equates to a comparatively paltry 12.4 inches. That said, the web reports a Chevrolet Corvette special sitting on 405-section tyres, on 24 x 15-inch wheels…and there are pictures to prove it.
To go still bigger as regards tyres, we must move out of the realm of car tyres. Bridgestone used to hold the record for making the world's largest production tyre, with its 59/80R63 V-Steel E-Lug S tyre. Fitted to earthmovers such as the Caterpillar 797B and 797F, these tyres stand 4.02 metres high – that's a little under thirteen and a quarter feet. Each earthmover wears six of these tyres.
Feeling your car tyres are a little underwhelming sizewise? There's more to come. The 63-inch OTR (Off-The-Road) tyres made by Titan are nearly fourteen feet tall and weigh a staggering 12,500 pounds apiece. Each tyre has a nominal load rating of a whopping 101 tonnes. Just don't expect your trusty tyre fitter to stock these 57.9 inch-wide Titan 59/80R63 tyres. Their size and their 5.66 tonne weight means the tyre racks probably won't cope.
Now that you're feeling distinctly ill-equipped with your pathetic little car tyres, the balance can be redressed with the aid of the 'Wind-Up'. This, the world's smallest road legal car, was built by British inventor Perry Watkins. Being a tiny car, the Wind-Up has tiny car tyres, which we'll come to in a moment.
Let's first see the vital statistics that demand such tiny car tyres. The Wind-Up is 41 inches tall, 51 inches long and 26 inches wide. Its Shanghai Shenke quad bike chassis is powered by a 150cc engine with continuously variable transmission. This gives the Wind-Up a top speed of 40mph, and a frugal thirst – it takes 70 miles to sip a gallon of fuel.
The Wind-Up's tyres come from small motorbikes. At the rear, it wears the wheels and tyres from a Honda Monkey Bike, the tyres being dinky 3.5 x 8-inch items. At the front, the Wind-Up rides on tyres from a 1939 Brockhouse Corgi paratrooper’s mini motorcycle, also 8-inch items.
Should you encounter a set of the miniscule car tyres that support the Wind-Up, there may be something more than a little familiar about the vehicle. Its 31.4 cubic foot body was sourced from a coin-operated ride favoured by little kids. Yes, Postman Pat's van got a new lease of life, courtesy of Perry Watkins.
Article Resource
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 Point Of No Return. Why Car Tyres Fail
Car tyres can fail for a variety of reasons. Some are more common than others but all are avoidable with a little foresight. So, let's look at some problems that can cause tyre failure, and learn how to avoid them.
Underinflation
Running your car tyres at too low a pressure has an immediate penalty. Underinflated tyres have higher rolling resistance than tyres running at the correct pressure. This means you waste fuel on pushing the tyres along the road. A less immediate but more punishing penalty comes from the same lack of pounds per square inch of air pressure inside the car tyre. Put simply, underinflated tyres can overheat. If the tyres overheat enough, it's bye-bye tread or tyre carcass – i.e. it's blowout time.
Inflating your car tyres correctly, to the pressure the car and/or tyre manufacturer recommends, is simple enough, and far less costly than new tyres or a spectacular blowout.
Overinflation
Given the above, it may seem logical to run your car tyres at a pressure higher than the one recommended. Wrong! Tyres running at too high a pressure lose compliance. Meaning? They can't cope well with road irregularities and will be more easily damaged. Such damage can occur deep within the tyre carcass and lead to a dramatic high-speed failure. Once again, the solution is to keep your tyres inflated to the correct pressure.
Excessive Speed
If you've saved a few pounds by buying car tyres that are under specified for your car's capabilities, there's no profit in preening yourself about it. Car tyres have a speed rating, denoted by a letter on the sidewall, for a reason. More highly-rated tyres have superior internal structures and can lose heat more efficiently than lesser items.
While your insurance company will take a very dim view of your running on inappropriate tyres, worse things can happen. Under specified tyres can fail, especially in hot conditions.
A good tyre bay will advise you on which speed rating is right for your car. Take the advice: always buy the right tyres.
Overloading
Car tyres carry a load rating as well as a speed rating and this too is with good reason. While overloading may not often affect passenger cars (except perhaps those used for towing), bigger vehicles can be seen wearing underrated tyres. This goes for 4x4s as well as pick up trucks and small to medium-sized vans.
Once again, a tyre bay is the source of knowledge – if in doubt, have your current tyres checked.
Road Hazards
Which road hazards? Good question, given the road offers plenty of hazards. Those particularly affecting car tyre integrity are pot holes, debris and kerbs. Hit any of these with any severity and you may damage a wheel, as well as a tyre. However, impact damage, even at parking speeds, can wreak unseen havoc within a car tyre.
When checking your car tyre pressures, look out for cuts, lumps and bulges – all can be harbingers of structural disaster in a tyre.
Excessive Wear
In these financially demanding times, it's understandable for drivers to try wringing the maximum life out of their car tyres. That said, taking a car tyre down to, or even past, the tread wear indicators moulded into its treads is false economy, not to mention dangerous.
This is another thing to check when you get down and personal with your car tyres. Remember that well worn tyres can lack structural strength as well as grip.
Article Resource
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.
Underinflation
Running your car tyres at too low a pressure has an immediate penalty. Underinflated tyres have higher rolling resistance than tyres running at the correct pressure. This means you waste fuel on pushing the tyres along the road. A less immediate but more punishing penalty comes from the same lack of pounds per square inch of air pressure inside the car tyre. Put simply, underinflated tyres can overheat. If the tyres overheat enough, it's bye-bye tread or tyre carcass – i.e. it's blowout time.
Inflating your car tyres correctly, to the pressure the car and/or tyre manufacturer recommends, is simple enough, and far less costly than new tyres or a spectacular blowout.
Overinflation
Given the above, it may seem logical to run your car tyres at a pressure higher than the one recommended. Wrong! Tyres running at too high a pressure lose compliance. Meaning? They can't cope well with road irregularities and will be more easily damaged. Such damage can occur deep within the tyre carcass and lead to a dramatic high-speed failure. Once again, the solution is to keep your tyres inflated to the correct pressure.
Excessive Speed
If you've saved a few pounds by buying car tyres that are under specified for your car's capabilities, there's no profit in preening yourself about it. Car tyres have a speed rating, denoted by a letter on the sidewall, for a reason. More highly-rated tyres have superior internal structures and can lose heat more efficiently than lesser items.
While your insurance company will take a very dim view of your running on inappropriate tyres, worse things can happen. Under specified tyres can fail, especially in hot conditions.
A good tyre bay will advise you on which speed rating is right for your car. Take the advice: always buy the right tyres.
Overloading
Car tyres carry a load rating as well as a speed rating and this too is with good reason. While overloading may not often affect passenger cars (except perhaps those used for towing), bigger vehicles can be seen wearing underrated tyres. This goes for 4x4s as well as pick up trucks and small to medium-sized vans.
Once again, a tyre bay is the source of knowledge – if in doubt, have your current tyres checked.
Road Hazards
Which road hazards? Good question, given the road offers plenty of hazards. Those particularly affecting car tyre integrity are pot holes, debris and kerbs. Hit any of these with any severity and you may damage a wheel, as well as a tyre. However, impact damage, even at parking speeds, can wreak unseen havoc within a car tyre.
When checking your car tyre pressures, look out for cuts, lumps and bulges – all can be harbingers of structural disaster in a tyre.
Excessive Wear
In these financially demanding times, it's understandable for drivers to try wringing the maximum life out of their car tyres. That said, taking a car tyre down to, or even past, the tread wear indicators moulded into its treads is false economy, not to mention dangerous.
This is another thing to check when you get down and personal with your car tyres. Remember that well worn tyres can lack structural strength as well as grip.
Article Resource
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.
Wednesday, 7 March 2012
Flat Lines. How To Change a Car Tyre Safely
A car tyre must be inflated to work properly. Should you suffer a puncture, you can change the wheel concerned. Here's how to do so in safety…
When
When to change a wheel becomes pretty obvious. A heavy pulling at the steering wheel and/or squirmy handling with assorted noises is usually sufficient to let you know a car tyre has deflated.
Where
Where to undertake a tyre change may seem obvious but this isn't necessarily so. The first and most important rule is to never, ever try to change a car tyre by a busy carriageway, be it a on a motorway hard shoulder or at the side of an A-road. Why? Quite simply, it is hugely unsafe.
So, what if you're caught out, on a busy road? Sometimes, it's possible to coax your car to a quieter location. Bear in mind that you'll need to find a level, firm surface to work on. If the car tyre has deflated fully, just pull up and call out the cavalry. The breakdown service will do the rest, after your mobile phone, or a roadside phone, has done its lifesaving bit.
How to prepare
A spot of preparation makes changing a flat car tyre much easier. Pull up in your chosen spot, apply the car's handbrake, put the car into gear (or 'park'), switch on the hazard lights and set up the car's warning triangle. This should be placed 45 metres (147 feet) behind the car.
The next stage in dealing with a flat car tyre is to have any passengers leave the car and stand well away from it, and from passing traffic. Then, it's time to extract the spare wheel, jack and tools – your car's handbook will tell you where they are to be found.
Jacking the Car
This step in the proceedings involves safety procedures, to which you must pay attention. First, you have to chock the wheel diagonally opposite to the one with the flat car tyre. No chock to hand? Then find a stone, brick or any other piece of debris that'll do the job.
Time for your car to go up in the world. There'll be a specific place under which the car jack must be placed. Once again, the handbook will tell you where this is. Do not improvise; only the proper jacking point will do. With the jack placed correctly, wind it up until it's bearing enough of the car's weight to not move.
Loosening the wheel nuts or bolts holding the wheel with the flat tyre comes next. These are always undone anticlockwise, with the wheelbrace that is in the toolkit. You may have to undo a locking wheel nut too – there's a key device for that.
Now, wheel fastenings can be very tight. Use the wheel brace so you'll be applying downward pressure (far less injurious if the tool slips). Loosen the fastenings first; the wheel can't turn because it's still on the ground.
Now, you can jack the car up. Do this steadily, until there is daylight between the flat car tyre and the roadside surface.
Changing the Wheel
Unscrew the fastenings completely one by one, removing the uppermost one last. You may need to 'persuade' the offending wheel to come off but be careful – over enthusiasm could cause the car to fall. For this reason, never let any part of you go between the car and the ground.
A car tyre and wheel combination can be heavy. Make sure that when lifting one, you’re on a firm footing with a straight back. Fit the spare wheel, securing it with the topmost fastening. Then, refit the remaining fastenings, tightening them only enough to seat the wheel firmly on the hub. Lower the car until the tyre is on the ground, and tighten the fastenings in a diagonal pattern. Now, you can stow the deflated wheel and tyre, put your tools away and continue your journey.
Finished?
Not quite, there are a couple of post-wheel change necessities. You need to get to a tyre bay, to have the wheel tightened to a specific torque – a repair on the flat car tyre is often possible. If you need to continue on the spare, you have to be sure that the car tyre on the spare wheel you've used is at the correct pressure. Finally, if the spare tyre is a space saver, there'll be limitations concerning speed and distance. The car handbook will show you what applies.
Article Resource
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.
When
When to change a wheel becomes pretty obvious. A heavy pulling at the steering wheel and/or squirmy handling with assorted noises is usually sufficient to let you know a car tyre has deflated.
Where
Where to undertake a tyre change may seem obvious but this isn't necessarily so. The first and most important rule is to never, ever try to change a car tyre by a busy carriageway, be it a on a motorway hard shoulder or at the side of an A-road. Why? Quite simply, it is hugely unsafe.
So, what if you're caught out, on a busy road? Sometimes, it's possible to coax your car to a quieter location. Bear in mind that you'll need to find a level, firm surface to work on. If the car tyre has deflated fully, just pull up and call out the cavalry. The breakdown service will do the rest, after your mobile phone, or a roadside phone, has done its lifesaving bit.
How to prepare
A spot of preparation makes changing a flat car tyre much easier. Pull up in your chosen spot, apply the car's handbrake, put the car into gear (or 'park'), switch on the hazard lights and set up the car's warning triangle. This should be placed 45 metres (147 feet) behind the car.
The next stage in dealing with a flat car tyre is to have any passengers leave the car and stand well away from it, and from passing traffic. Then, it's time to extract the spare wheel, jack and tools – your car's handbook will tell you where they are to be found.
Jacking the Car
This step in the proceedings involves safety procedures, to which you must pay attention. First, you have to chock the wheel diagonally opposite to the one with the flat car tyre. No chock to hand? Then find a stone, brick or any other piece of debris that'll do the job.
Time for your car to go up in the world. There'll be a specific place under which the car jack must be placed. Once again, the handbook will tell you where this is. Do not improvise; only the proper jacking point will do. With the jack placed correctly, wind it up until it's bearing enough of the car's weight to not move.
Loosening the wheel nuts or bolts holding the wheel with the flat tyre comes next. These are always undone anticlockwise, with the wheelbrace that is in the toolkit. You may have to undo a locking wheel nut too – there's a key device for that.
Now, wheel fastenings can be very tight. Use the wheel brace so you'll be applying downward pressure (far less injurious if the tool slips). Loosen the fastenings first; the wheel can't turn because it's still on the ground.
Now, you can jack the car up. Do this steadily, until there is daylight between the flat car tyre and the roadside surface.
Changing the Wheel
Unscrew the fastenings completely one by one, removing the uppermost one last. You may need to 'persuade' the offending wheel to come off but be careful – over enthusiasm could cause the car to fall. For this reason, never let any part of you go between the car and the ground.
A car tyre and wheel combination can be heavy. Make sure that when lifting one, you’re on a firm footing with a straight back. Fit the spare wheel, securing it with the topmost fastening. Then, refit the remaining fastenings, tightening them only enough to seat the wheel firmly on the hub. Lower the car until the tyre is on the ground, and tighten the fastenings in a diagonal pattern. Now, you can stow the deflated wheel and tyre, put your tools away and continue your journey.
Finished?
Not quite, there are a couple of post-wheel change necessities. You need to get to a tyre bay, to have the wheel tightened to a specific torque – a repair on the flat car tyre is often possible. If you need to continue on the spare, you have to be sure that the car tyre on the spare wheel you've used is at the correct pressure. Finally, if the spare tyre is a space saver, there'll be limitations concerning speed and distance. The car handbook will show you what applies.
Article Resource
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.
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