A Matter Of Choice - Selecting The Optimum Car Tyres

Car tyres are car tyres, right? Well, they’re all round, black things that go between your wheels and the road. However, choosing the right tyres for your car and, equally important, for your needs is imperative. Here are some pointers to help you make the right choice.

The Right Type of Tyre

There are five distinct tyre types you can choose from and it isn’t always a case of one tyre type for one car; the choice is also about usability.

Standard car tyres, otherwise known as all-season tyres, are the least specialised. They are suitable for year-round use, in wet or dry conditions. In some respects, run flat tyres lie in this arena. Run flat tyres can do exactly what their title suggests; you may continue using them, albeit at a given maximum speed over a specified mileage, even after a puncture.

The third variety of car tyres differs in the conditions to which they’re suited. Winter tyres can handle colder conditions better than standard tyres and they generally have a tread pattern with larger blocks in a more open pattern, for better grip. Our fourth tyre type is also based on the conditions to be encountered, specifically in terms of terrain, rather than climate. All-terrain tyres can cope with mud, sand and gravel and are often found on 4×4 vehicles used off the road. However, the additional grip in adverse conditions has a cost. All-terrain tyres are noisy when used on ordinary tarmac roads.

Lastly in this quintet, performance tyres are for performance cars. As well as offering superior grip in wet or dry conditions, performance car tyres usually have a higher speed rating.

The Right Tyre Size

When it comes to car tyres, it is anything but a matter of one size fits all. The manufacturer’s recommended fitment may be found in your car’s handbook and if in doubt, you could always have replacement tyres like the existing ones. However, small changes in tyre section and width can be accommodated, often beneficially. The staff of a good car tyre retailer will be happy to recommend the best tyres for you.

The Right Tyres for your Driving Needs

While remaining within the manufacturer’s specified parameters, you can ring the changes by using car tyres that suit your driving style and/or particular needs. You may need economy tyres for better mileage from your gallon. Certain tyre types are particularly quiet in use and therefore better for motorway use. Similarly, some tyres are well suited to stop/start motoring. As mentioned above, you’d be well advised to consult the tyre retailer.

The Right Price

The price of car tyres varies considerably but here, commonsense must play an important role. You can’t for example, have economy tyres fitted to a high-performance sports car and expect good results, not to mention longevity. Conversely, there’s little point in having high specification tyres fitted to a car that covers a small yearly mileage. However, if you use your car daily, economy tyres could represent false economy; budget tyres may not last as long as better quality items.

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.

Top Tips For Pampering Your Tyres

Car tyres are tough, which is fortunate, as they have to be tough to survive. That said, there are ways that your tyres can be given an easier life. Using them can save you money in the long run.

Pressure salesmanship

Running car tyres at the wrong pressure is a surefire way of shortening their life. Underinflated tyres flex more, which causes them to run hot, which makes them pensionable long before their time. Underinflation wears out tyre shoulders, and the lack of air pressure makes them less able to defend your wheels from assaults by speed bumps and potholes.

As car tyre pressure reduces, rolling resistance increases. Meaning? Soft tyres take more fuel to push along. Simples, as that meerkat says.

In its way, overinflation is just as bad. Tyres running on tiptoe sacrifice grip and ride comfort. Overblown tyres also wear out the centre of their treads. Paradoxically, over inflation doesn’t enhance the tyres impact resisting abilities.

A weekly tyre pressure check is hardly onerous. Buy a good pressure gauge and find a forecourt that isn’t so cheeky as to charge for air. You’ll find information about the correct tyre pressures in your car’s handbook and probably on a sticker on one of the car’s door pillars.

A question of balance

When checking your car tyre pressures, you may notice little metal blocks attached to your wheel rims. These are balance weights; they’re there for a reason. Anyone who’s driven a car with a lost balance weight will tell you what the results feel like. A seriously unbalanced wheel will put the integrity of the fillings in your teeth at risk. Equally, anything more than minimal braking will make you wonder why the ABS has deployed, making the brake pedal vibrate like the firing pedal of an ack ack gun.

In practice, even a mildly unbalanced combination of car tyre and wheel will be costly. The increased level of vibration puts stress on several components. The tyres itself will wear faster. The need for the suspension joints to cope with additional strain will cause them to wear. Perhaps more noticeably, you’ll feel the strain too; tyre imbalance increases driver fatigue.

Toeing the line

Wear and tear can put a car’s wheels out of alignment. Misalignment makes cars suffer, and not only in an obvious way. Car tyres like to run straight and if they can’t, they object by wearing out faster. Too much toe-in (cross-eyed wheels) makes the tyres’ outer shoulders wear, and toe-out (diverging wheels) makes the inner edges wear. Apart from being costly, this affects steering sharpness and braking.

Having your wheels aligned and balanced when necessary is a lifesaver for your tyres. Moreover, it is far cheaper than new tyres and possibly a suspension and steering overhaul.

Lastly, drive sympathetically, or you’ll burn out your tyres in no time. Make a point of inspecting your tyres regularly and remember that ten yards running flat will kill a tyre. Your tyres look after you; if you look after them, they’ll continue returning the favour.

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.

Strategies For Saving - Cut Car Tyre (And Other) Costs

In these dark times, we must all tighten our belts, as well as having them tightened for us by the powers-that-be in Whitehall. It therefore makes sense to do what we can to save on our motoring costs, from saving fuel to making our car tyres last as long as possible. Here are a few hints to deter the wolf from ringing your doorbell too frequently.

Turning fuel into forward motion is a conversion of energy, from potential to kinetic. Maintaining as much of the former while benefitting from the latter involves applying efficient practices. Maximizing mpg starts with starting the car. Cold car tyres are softer than hot ones and cold engines are distinctly fuel-inefficient. So, if it’s a short trip, don’t use the car. Equally, you can save by being gentle on the gas when the car is cold.

Once the engine (and the tyres) are hot, keep to the highest possible gear. This doesn’t mean accelerating hard until you can use top gear. Instead, keep the rev counter needle low on the scale and change up sooner to keep it there. At the top end of the speed scale, observe the speed limit. We all know that speed camera or police radar gun fines aren’t cheap and they increase insurance premiums. It’s also the case that pressing on costs; the difference between 60 and 70 mph cruising can be up to 5 mpg in some cars.

There are several ways in which life can be a drag or rather, drag can be a costly luxury. Underinflated car tyres give greater rolling resistance and increase fuel consumption. Got a roof rack? If you have and it’s empty, dismount it. The air drag of even an empty roof rack is quite startling and you can do without it, and the weight of the rack itself. Similarly, air conditioning is lovely, especially on a muggy day, but it costs. Specifically, it can cost you to the tune of an 11 percent reduction in mpg. This is about balance. Open car windows create aerodynamic drag too. In general, open the windows to cool down around town but at over 40 mph, use the air con.

Underinflated car tyres aren’t the only things that weigh down fuel consumption figures. Some people carry the essentials but if your car is full of junk, every kilogram is costing you fuel. Figure out how likely you are to need golf clubs, dog blankets, Thermos flasks and half a dozen old newspapers on the way to the supermarket. This is a question that answers itself!

Some savings are more obvious than others. The number of miles of tarmac that pass under your car tyres is probably a given. That said, are you using the most fuel-efficient route? Try to avoid traffic if you can and keep up to date with en route road works. Motorways and dual carriageways, without all that thirsty stopping and starting, save fuel, as does the shortest route. Remember that a motorway detour, though a little longer, could be less costly overall.

Lastly, hidden costs. This is all about shopping around. Many things, such as new car tyres, may be what’s called a distress purchase. However, the firms selling the tyres, car insurance, spare parts and even fuel are in distress too. It’s worth looking out for the best deal.

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.

Car Tyre Calculations: CRF

Looking at the above title, you could be forgiven for wondering, ‘What on Earth is a CRF?’ .As it happens, a CRF is one of those Michael Caine things: not a lot of people know what one is. To put you out of your misery, a CRF is a car tyre science value. It stands for the Coefficient of Rolling Friction. Still mystified? Don’t be - all will become clear!

A CRF is a figure that relates to how much force it takes for a car tyre to be driven along the road. The CRF is used to calculate the amount of drag, otherwise known as rolling resistance, that the tyre has in use. If you need a still simpler example of what rolling resistance is all about, imagine that you’re trying to ride a bicycle with flat tyres. Is it easy? No it isn’t, because the tyres have a high CRF.

We can use our new knowledge practically, to calculate how much force a typical car uses to push its tyres along a road. The force is needed to overcome friction and we can calculate it simply: if we know the tyre’s CRF and the weight it is carrying, we can calculate the force used.

In this example, our car weighs 4,000 pounds and the tyres have a CRF of 0.015. If we now multiply one figure by the other, we can find out the force in pounds. So, 4,000 x 0.015 equals 60 pounds. Does this car tyre science figure mean anything yet? Not really, because we’ve one more sum to do.

The next calculation uses an equation that can tell us how much power the car uses to push its tyres along. The equation is simple enough and we can use it with some figures that are, again, typical. So, Power equals Force multiplied by Speed. Adding figures into this equation shows that the power used is dependent on the speed at which the car is travelling.

Our theoretical car tyres, therefore, use up more power as the car’s speed increases. At 55 miles per hour, they use 8.8 horsepower. At 75 miles per hour, they consume 12 horsepower. Moreover, like with our flat-tyred bicycle, the lower the air pressure in the tyres, the higher the CRF.

Apart from using more power and therefore burning more fuel, what does this friction do? As you can neither create nor destroy energy, it changes its form. In fact, it turns into heat energy. Should the road surface be soft, more heat is transmitted to the ground and less builds up in the tyres.

This car tyre theory is interesting but asking the question, ‘what is it for’ brings an equally interesting answer. Tyre manufacturers sometimes publish CRF figures for their various kinds of tyre. The lower the CRF the less the rolling resistance or, to put it simply, drag. The less the drag, the better the economy. This also shows what is costly about running your car tyres at too low a pressure. However, remember that wasted fuel isn’t the only cost of under inflation.

Lastly, here are the CRF figures for some typical wheel and tyre (and just wheel) configurations.

A low rolling resistance car tyre’s CRF is 0.006 to 0.01

A conventional car tyre’s CRF is 0.015

A lorry tyre’s CRF is 0.006 to 0.01

A train wheel has a CRF of 0.001

Meaningless figures? Look at the one for the all-iron train wheel and imagine how much engine power is used to keep it rolling. As the Americans say, go figure!

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.

Inflation Rate: Car Tyre Inflators Under Scrutiny

Appearances can sometimes be deceptive. Like the first part of this title, for example. In this instance, the article isn’t about money, or the consumer price index. It can, however, be about saving you money. Buying a car tyre inflator can be a costly business. On the other hand, since a good one makes inflating your car tyres easier and quicker, it will tend to make you carry out this simple chore more regularly. This in turn means your tyres will remain at the correct pressure; you’ll save money by not burning extra fuel to push under inflated tyres along, your tyres will last longer and will be less likely to fail or suffer damage from overheating.

What are car tyre inflators about? They’re a simple electric pump for blowing up your tyres. Yet, a quick look through the available inflators reveals a lot. Some inflators are powered by your car’s battery, usually via the cigar lighter socket. Some inflators are rechargeable. Some are claimed to be quiet. Some are billed as being rapid inflators - one example inflating a tyre from totally flat to full pressure in four minutes. Others aren’t so rapid - one on test took 15 minutes to do its work.

The car tyre inflator’s abilities don’t stop there. Many have a number of LED lights, so you can utilise their inflating facility at night, which could be useful in an emergency. Most are digital, in that they have a digital readout for the pressure of the tyre to which they’re connected. This readout can usually be set to give a figure in the desired scale, that is pounds per square inch, Bar or kPa (Kilopascals).

Another benefit of a good car tyre inflator is that it can do some of the work for you. True, you have to connect it to the electricity supply (or make sure it’s fully charged). You also have to connect it to the tyre you want to inflate and you ought to oversee what it’s up to. However, the majority of good car tyre inflators feature an auto shut off facility. When the tyre is at the right pressure, the inflator stops inflating - it’s that simple.

All this begs a rather obvious question. Which one do you buy? Well, this is not a buyer’s guide. However, we all know that the Internet is laden with user reviews as well as advertisements. You can spend a happy hour doing your research, on which car tyre inflator has the best reviews.

There are some aspects of car tyre inflators that you may want to consider before buying. A quick look through some of the web tests of these devices reveals much. One point relates to a very old, well-worn adage: you get what you pay for. This is scarcely surprising and you won’t get a lot for very little money. You will have the choice between quiet inflators, fast ones, rugged ones and so forth. However, one overarching drawback seems to apply to even some of the more expensive car tyre inflators. More than one test website offers the advice to add a top-quality tyre pressure gauge to your shopping list. Quite a number of the tests discovered that the on-board digital pressure gauges were not necessarily accurate. Comparison will out, of course, during your research. On the other hand, you shouldn’t really need to buy an additional pressure gauge. As a responsible motorist, mindful of your own safety, that of others and the way in which incorrect pressure shorten tyre life, you already have a quality pressure gauge. Don’t you.

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.

Still More Tyre Trivia: Fascinating, Educational Car Tyre Facts

Low Cunning

Fashion has followed performance, which is why ultra low-profile tyres have become more common. Every car tyre has an aspect ratio, which is a comparison of its height in relation to its width. A ‘full profile’ tyre has a section height that is 80 to 85 percent of its width; such tyres are rarely seen these days, unless a classic vehicle is riding on them.

Aspect ratios have been falling over the years. 70 percent profiles came along, followed by 65 percent, 60 percent and so on. Nowadays, 45 percent profile tyres can be seen on high-performance cars and the current low figure is a mere 35 percent. Beware though, ultra-low profile tyres may look thrilling and they certainly offer tremendous performance. There is, however, a twofold cost. The lower you go, the more ride comfort suffers. What’s more, wheel damage from touching a kerb, or hitting a pothole or debris in the road, is far more likely.

Formula One Facts

A Formula One car can accelerate from rest to 99.42 miles per hour and decelerate back to zero in four seconds. Even though such a car weighs only a little over half a tonne, the breathtaking forces involved clearly give the tyres a hard life. Here are some captivating facts from F1’s sole tyre supplier, Bridgestone.

The company produces 40,000 of its Potenza F1 tyres each year and takes 1,800 tyres to each grand prix.

During the 2008 grand prix season, 19,435 laps were completed on Potenza F1 tyres.

A Bridgestone tyre fitting team can fit 56 car tyres per hour, that’s 14 sets of tyres. Sixty of the company’s personnel attend each grand prix, taking with them 12 tonnes of specialised equipment.

At just over 186 miles per hour, Bridgestone wet weather tyres displace 61 litres of water per second.

Potenza F1 tyres are built to last - for around 93 to 124 miles under racing conditions.

Back to the Real World

Now for some less esoteric facts and figures, from the everyday world of motoring.

About 75 percent of British motorists are driving on under-inflated car tyres.

What this is doing to their carbon footprints isn’t known but it is costing them over 2 billion pounds every year.

Approximately 12 per cent of the cars in the UK have at least one defective tyre.

Another 12 percent have a tyre with less than two millimetres of tread, which is legal but decidedly unsafe.

Ninety percent of Britain’s motorists don’t know the pressure to which their tyres should be inflated.

Continental Tyres carried out a study, which discovered that 40 per cent of British motorists claim never to have checked the pressure in their car tyres.

More than 40 per cent of drivers admitted that they didn’t know how to check tyre tread depth. Seventy per cent had no idea of the legal minimum tread depth, which is 1.6 millimetres over 75 per cent of the tread’s width, in a continuous band.

About 20 percent of drivers confessed to driving on tyres that would probably not meet legal tread limits.

These sobering figures, apart from highlighting the need for a certain amount of education for UK drivers, suggest something else. It’s comforting that the average UK driver isn’t in charge of Formula One car tyres!

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.

Little Helpers For Car Tyres

In many respects, modern cars are computers riding on tyres. Much of what happens below decks may seem to be under the driver’s control but in fact, computerised assistance is ever-present and sometimes, the computers take over. Here, we can take a look at some computer-controlled elements that specifically relate to the work of car tyres. We’ll find ourselves knee deep in acronyms but don’t worry, each will be explained.

Lets start with ABS. Which is? The Anti-lock Braking System. ABS first appeared in 1929, when Gabriel Voisin, a French aircraft and car engineer, developed a working system for aeroplanes. In the production car world, Chrysler later teamed up with Bendix to produce ‘Sure Brake’. This, a fully computerised all-wheel ABS system was available on the 1971 Imperial. Not to be outdone, General Motors stopped car tyres skidding with ‘Trackmaster’, a rear-wheel only system that first appeared on their 1971 models.

So how does ABS help car tyres? A typical system has a central electronic control unit (ECU), a speed sensor at each wheel, and hydraulic valves within the braking system. Under hard braking, a car wheel that is rotating significantly slower than its counterparts is on the point of locking. The ECU detects this and commands the appropriate hydraulic valve to reduce the braking force at that wheel. As the wheel speeds up again, the ECU reimposes full braking force - this can happen up to 20 times per second.

What does this mean in practice? When the ABS keeps the car tyres at the point of locking but doesn’t let them lock, the car is being braked to the limit of the tyres’ adhesion. This represents maximum braking efficiency. Moreover, skidding car tyres have actually lost their grip. The driver may be applying maximum braking force and locking the wheels but braking and steering control are lost. Under the influence of ABS, it becomes possible to still steer the car around an obstacle.

Now for another acronym, which describes a system that has evolved from ABS. Electronic Stability Control, or ESC, adds two further sensors to the ABS armoury. The first, a gyroscopic sensor, can detect when the car’s direction of travel doesn’t accord with the position of the second, the steering wheel angle sensor. The ESC’s software can then apply braking force to up to three of the wheels individually. Consequently, the car tyres’ grip is used to assist in making the car travel in the direction the driver has chosen. CBC, or Cornering Brake Control, is a refinement in ESC. This system can control the ABS, telling it that the wheels on the inside of the curve being taken should be braked harder than the those on the outside. It also dictates how much additional braking force is applied.

Paradoxically, an ABS-related system can help car tyres to retain grip under acceleration. A Traction Control System, a.k.a. A TCS, detects a driven wheel that’s spinning and briefly applies braking force to allow the spinning car tyre, or tyres, to regain traction. More sophisticated TCS systems can control the throttle level simultaneously, cutting power to the spinning wheels.

As you can see, these electronic aids to safety are complicated. Different manufacturer’s calling them by alternative names further complicates the issue. For example, some call their TCS an ASR, an Anti Slip Regulator. The above is a very simplistic explanation of such systems and there are other, similar systems in use. The bottom line is that they all help a car’s tyres make maximum use of the grip they offer.

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.