Saturday, 20 November 2010

Baywatch: What Makes A Good Car Tyre Bay?

We’ve all driven past them. Tyre bays might offer the best prices, two car tyres for the price of one, special deals on four-tyre sets and all manner of other tempting offers. This is, of course, just advertising and, as Joseph E Levine said, “You can fool all the people all the time if the advertising is right and the budget is big enough.” Now, it’s true that car tyres are often a distress purchase but even so, knowing what makes is good tyre bay is knowledge worth having.

So, what makes a good tyre bay? The answer is a two-word one: products and services. Here, it is not only the range of products and services but their quality that matters. Here’s what to look for in your car tyre-buying expeditions.

It’s obvious that a tyre bay is there to sell you car tyres. What you need to know first is whether the tyre bay is going to sell you new tyres. If you can, take a look at the stock on the shelves – you’re looking for the DOT codes. If this has three digits, walk away – four-digit codes came in after the year 2000. The way to read a four-digit code is easy to understand. The first two figures represent a particular week in the year denoted by the last two figures. So, a tyre marked 5009 was made very near the end of 2009. Car tyres have a six-year shelf life – and you can always check the tyres’ age before they’re fitted.

Speaking of tyre fitting, tyre bays have this down to a fine art. Given that car wheels and tyres live in a grimy environment, some grubbiness is acceptable even in a good tyre bay. However, untidiness should be frowned upon. If the tool cabinets are well organised, they’re liable to be well equipped. Similarly, tidy floors and a lack of overflowing bins and dead tyres underfoot denote an efficient workshop.

Wheel alignment is a service offered by many tyre bays. The days of the old Dunlop optical alignment gauge, effective though it was, are long gone. If you see computerised, four-wheel geometry wheel alignment, maybe with the involvement of measurement using lasers, you can rest assured that you’re in a good tyre bay. Remember that poor wheel alignment is a car-tyre eater.

Much the same goes for wheel balancing, which is an essential part of tyre fitting. On unbalanced tyre/wheel combinations, car tyres work less well and wear out faster. In the (very) old days, a balancing kit that involved sitting a wheel and tyre on top of a milk bottle was touted. Computerised wheel balancing is the norm nowadays – accept nothing less.

Many tyre bays are no longer transfixed, work-wise. Putting the tyre fitting and wheel balancing machinery into a van, along with an air compressor, equals mobile tyre fitting. You may take advantage of this service and some tyre bays offer a ‘call and inspect’ service, particularly for car fleet operators.

While there are other services offered by tyre bays, such as air-conditioning checks, the above suggest that a tyre bay offering these goods and services is up-to-date as well as on the ball. This in turn suggests that one very important element of tyre supply and fitment will be available and reliable. Never forget that the staff in a good tyre bay can advise you about choosing the best car tyres for your needs.

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.

Saturday, 30 October 2010

Protection Racket: Locking Wheel Nuts Keep Car Tyres Safe

There are certain, indisputable facts in life. One is that car tyres – and car wheels – are expensive. Consequently, the, er, light-fingered among us have been known to lift our wheels and tyres, by first lifting our cars on to a convenient pile of bricks. In the relatively recent past, car alarms have become smart enough to detect when a car is being jacked up and they can tell everyone in the vicinity all about it. This is ‘active security’, which is a subject in itself. In this article, we’ll look at an example of ‘passive security’.

Passive security needs no power source: it is a barrier rather than a whistle-blower. All it need do is be there to be effective. Sometimes, passive security devices are evidently present. However, devices that mechanically prevent car wheels – and car tyres – from being stolen, tend not to shout about it. The thieving fraternity knows what locking wheel nuts or bolts are about and it’s rare for a vehicle to lack them nowadays.

How, then, do these devices work? Their operation really couldn’t be simpler. If you attach your car wheels to your car’s hubs with four or five nuts or bolts apiece, and those nuts or bolts have a hexagon head, the danger is obvious. Replace one fastening per wheel with a fastener that needs a key of some sort to permit it to be removed and the solution is present and evident. Your wheels and your car tyres are as safe as they can be made.

The obvious question that arises is about the key itself. This, rather than being a key as such, is usually an adaptor, which allows a wheel nut/bolt spanner to be used to remove the special fastening it fits. So, what to do with the key, or adaptor? Most people keep it in the boot, or perhaps in the car’s glove box. This means your car tyres and wheels are protected by the car’s alarm. This could be worse, of course, and what is relevant is that you never know when a car tyre needs to be changed. The only watchword exists when you have to leave your car unattended for a while, say in an airport car park. Having seen a BMW on bricks and wearing no wheels, I can safely suggest that if the wheel key had been in Spain or France with the car’s owner, the wheels and tyres would probably have been present when the car’s owner returned.

The locking of car wheels and tyres has been refined to the extent that corrosion and wheel balancing problems are a thing of the past. There are some cheap sets of locking wheel nuts/bolts on the market; these can fail even when used properly, so avoid them. Nevertheless, another question arises: what happens if you’ve lost the key to an unarguably tough locking wheel nut or bolt? One person on the Internet resorted to using a power hacksaw to dismantle the offending wheel and tyre. However, radical resection isn’t really necessary. Car tyre fitters have generally encountered this problem before, and keep a range of tools, at least one specifically designed for this task.

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.

Sunday, 29 August 2010

More Star Cars - Movie Flyers, On Tyres

The star cars that make some movies memorable often start life as completely standard vehicles. They rarely stay that way and they always attract a following. So let us follow in the tyre tracks of some Hollywood luminaries.

Our first diva was in fact six cars, of which four still exist. In many respects it was ahead of its time; by the end of the first movie in which it appeared, it was running on rubbish. This early green machine, Doc Emmet Brown’s time-travelling car was a DeLorean DMC12 and it first burst on to our movie screens in 1985. A trilogy of movies and many years later, Christopher Lloyd (Doc Brown) is 71, and Michael J. Fox (Marty McFly) is 49, has Parkinson's disease and an honorary doctorate from the Karolinska Instituet. Of the four DeLoreans remaining, two are studio tour stars at Universal, one lives on the ceiling of Planet Hollywood in Honolulu - and the last one is being restored. Some of the cars that John Z. Delorean made still set tyres to tarmac, and some among their number have attained a degree of immortality.

'So cool it hurt' is an epithet that applied to the late Steve McQueen, and his handling of the 1968 Ford Mustang GT390 Fastback he used in 'Bullitt' did his reputation no harm at all.

During the seven-minute, tyre-burning chase sequence with the baddies' Dodge Charger R/T440, McQueen did most of the driving and there was no camera trickery. Both the Mustangs used were given tuning tweaks so they could keep up with the more powerful Magnum Chargers, and one of each was given beefed-up suspension and a full roll cage.

All that drifting car tyre smoke was real, as was much of the San Francisco traffic. One thing, however, was a later addition. The full-blast V8 engine sounds came from an example of the GT40, Ford's four-times Le Mans winning racing car.

Now for a quirky one. What has massive tyres, ten carburettors with gold plated intake pipes, and a huge, Ford Cobra motor? Need more clues? How about Jahns high-domed pistons and an Iskendarian camshaft? Still too techy? Ok then.

Customizer George Barris built the idiosyncratic vehicle in question. It was based on a lengthened 1923 Model T ford chassis and had a custom body. Still struggling? Alright, here are some names. The car was featured in a 1960s TV comedy starring Fred Gwynne, Yvonne De Carlo; Al Lewis played Grandpa. Those who are thinking of Clive Dunn at this stage can go to dunce's corner right now. However, the names Herman and Lily might ring some bells. Yes, it's the Munster’s Koach.

This unique car toured the 'States extensively in the 1970s, and pre-tour, George 'Batmobile' Barris gave it a new paint job. The car now rests in peace, in the 'Cars of the Stars' museum, in Keswick, Cumbria.

Finally, a vehicle with just 114 horsepower from its 4.9-litre, six-cylinder engine is hardly likely to set tyres or tarmac alight, especially with its three-speed automatic transmission. However, the very same vehicle had its charm and made us laugh, even if it was slow. The film 'Dumb and Dumber' featured this 1984 Ford Econoline van, complete with floppy, furry ears, a lolling tongue and a full fur coat. Jim Carrey and Jeff Daniels' 'Mutt Cuts' van didn't stay long but the movie wouldn't have been the same without it!

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.

Saturday, 21 August 2010

Car Tyre Clearance: Making Sure Your Wheels Measure Up

There’s nothing in the rule book that says you must keep the wheels your car had on when it arrived. Many people change their wheels, for a variety of reasons. Some want a different style of wheels, some want wider wheels and most want alloy wheels. A change of wheels usually means a change of car tyres. That is no problem in itself but there is a trap into which a lot of people have fallen with a resounding clatter.

The thing is, any car wheel will accept one or more different sizes of car tyre. There is, however, more to car wheels than just rim diameter and width. Ignore the other measurements or get them wrong and disaster looms. In short, you can find there’s a clash between your car tyres and its bodywork. This can happen with steering or suspension movement and often, it happens just the once, immedately before the tyre and bodywork wreck one another.

The first measurment is Pitch Circle Diameter, or PCD for short. This is nothing to do with car tyre to bodywork clearance but if you get this wrong, the wheels won’t fit. The PCD is the diameter of a circle drawn through the centre of your wheel mountings, be they studs or bolts. The wheels obviously need the right number of stud or bolt holes but you also need to ensure that the wheel nuts or bolts have the right thread and profile for your car’s hubs, and that they are correct for use with the wheels you’re using.

Now for the easy ones: rim width and diameter. You could go for the standard measurements here. However, many people want bigger wheels and low profile tyres. Fair enough – just ask the wheel supplier, who you can always blame if something doesn’t fit. It’s also important to make sure that the wheels can accommodate your brakes. Big wheels and low profile tyres were invented, in part at least, to allow for bigger brakes to be crammed in. These days, clearances are close and it’s problematic if your wheels and disc calipers rub each other. This makes only one difference to the car tyres: they won’t work too well if the wheels can’t rotate.

So, we come to the tricky one, the knotty problem of wheel offset. This is most easily understood with a little bit of theory. Imagine a car wheel sawn in half across its diameter. If you were to draw a line through the centre of the wheel rim, and this line was to coincide with the wheel’s hub mounting face, the wheel offset would be zero. If, as is common, the hub face lies outboard of the centre line, the wheel has positive offset. Conversely, if the hub face lies inboard of the centreline, the offset is negative. The degree of offset, apart from altering wheel clearance, has a profound effect on the behaviour of your car tyres.

Visually, positive offset places the car tyre further under the car’s wheelarch. Negative offset makes the tyre carcass sit further outboard. In either case, provided you don’t choose a seriously large figure in relation to what is standard, the car tyres won’t cause difficuties. That said, there is a danger in choosing too radical an offset, as this figure (usually expressed in millimetres) affects steering. You could find that your steering has becomes mysteriously heavy. Worse still, you could find it’s become over-light, to the extent that straight line driving becomes a thing of the past.

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.

Saturday, 31 July 2010

Car Tyres Teasers - Important Facts You May Not Know

‘We’re on your side.’ This sounds like the tag line in an advertisement but here it refers to the codes on a car tyre’s sidewall. Most of us know the obvious ones like those referring to wheel diameter and tyre section. There are, however, many other pieces of vital information to be found, moulded into the sidewall. Let’s consider some of the more important ones.

Did you know that some car tyres have a marked rating that indicates how well they handle heat build up? If you see a mysterious “A” on a tyre, it has the highest rating. A “C” denotes the lowest.

The traction rating shows how well a tyre can stop you on a wet road. This rating goes from “AA” to “CC”. No prizes for guessing which is the best.

Now for some numbers. Tread wear ratings go from 60 to 600 in increments of 20 and the figure shows how long the tyre is expected to last. In theory, a tyre marked “200″ should last twice as long as one marked “100″. This is, however, a relative rating. The actual tyre life will depend on many factors, including your driving style, the road surfaces encountered, correct wheel alignment and the right tyre pressure. Think ‘benchmark.’

The speed rating a tyre carries is extremely important. Using over-specified tyres is a (very expensive) upside here; tyres for high-speed use can be used at lower speeds. On the other hand, if the speed rating is too low and you have an accident, your insurance company may take a dim view of the tyres your car was wearing at the time. Speed ratings run from “L” (75 mph) to “Z” (150 + mph). Currently, H-rated tyres (130 mph) hold the largest percentage of new tyre sales.

So much for speed, what about load? Yes, car tyres tell you about the load they are capable of carrying, They have a marked load index (LI), which is valid for sub-130 mph speeds. Load indices range from 50 (190 Kg) to 169 (5,800 Kg) but the calculations are a touch complex. Let’s say you have a car that weighs 2 tonnes, or 2,000Kg. Divide this by four to get the weight on each wheel; this equals 500Kg. So far so good, but, do you know that all four wheels carry 500Kg or is one end of the car heavier than the other? In practice, it’s usual to add a percentage to cover such factors.

In our example, then, the car needs tyres with a load index of 84. We can add 20 percent, giving a weight bearing capacity of 600Kg. Therefore tyres with a load index of 90 will do very nicely. In reality, a car tyre’s load rating will exceed its actual needs by a long way. However, when speeds reach 130 mph or more, the load index calculations change dramatically. For reasons far to technical to explain here, the theoretical load rating decreases as road speed rises. In the event you run a very, very fast and heavy car where the speed cameras don’t work, there are experts in such matters. Find one!

Lastly, you should never use a tyre more than 6 years old. The date of manufacture is part of the DOT code marked on one sidewall. For example, a tyre marked “2709″ was made in the 27th week of 2009.

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.

Saturday, 24 July 2010

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.

Friday, 16 July 2010

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.