Superstars Miranda Kerr, Catherine McNeil & Abbey Lee Kershaw – all from DownUnder – are among the 11 models in this year’s Pirelli calendar.

The Pirelli calendar is about to be released to its usual select audience of 10,000 world wide.
You first read about it on the Cars Guide site, and the three Aussie models follow a well worn trail of Australian pulchitude that has adorned this calendar over the years, at exotic locations all over the world.

But here’s the twist.

The review of the Pirelli calendar on the Cars Guide site is written by a lassie called Karla Pincott. So what’s remarkable about that?

All it shows to me is that the smell of rubber dust in the nostrils can even jump a generation or two. I bet London to a brick that she’s related to an old pioneer of the Australian retreading industry, Jim Pincott, who used to make the “Kookaburra” buffing blades used to prepare a tyre for retreading, and a whole range of retreading equipment. Jim had a flourishing business in the fifties/sixties, and his involvement in the industry dated back to the days of Sir Frank Beaurepaire. So when I said “pioneer”, I meant it!

Tubeless Tyre Valves

The little rubber and brass valve that holds the air in your tyre, and admits new air, is one of the world’s most successful inventions. William Schraeder designed its fundamentals nearly 120 years ago.

The little “springy thingy”, called the “valve core”, that screws into the brass valve really hasn’t altered all that much in that time, and all you need to remove it and let the air out, is a slotted valve cap. Or you can just depress the little button in the centre and you get the same effect, only slower.

Yet when you buy a new tyre, the fitter always replaces the valve. Why does he bother?

The modern tubeless snap-in valve is compressed into a hole in the rim to provide a seal. A brass stem is adhered to a rubber skin, with a domed shape on the inside of the wheel to prevent it being blown through the hole by the air pressure.

 Over time, the degree of compression is lowered (it doesn’t fit as tightly). It may even crack around the groove in the rubber which lodges in the rim hole due to flexing.

The valve actually flexes as the wheel revolves, particularly if it is a long one designed to protrude past the wheel trim. Ultra-high-speed photographs have shown the valve actually touching the rim at right angles at very high speeds. Also the heat during service causes the bond of the brass to the rubber to deteriorate, and if this bond ruptures, the stem blows out, and the tyre goes down quickly.

So reliability is what it’s all about. It’s much better in the long run to replace it after one tyre life.

You can contribute by using dust caps or valve caps, and giving a blast of air around the valve before you clamp on the air chuck, which you should do monthly. If you suspect a leaking valve, a “dob of spittle” on the end of your finger into the brass stem is the tried and true method. If it bubbles, first check the valve core is tight. If it is, loosen it, let some air our, then retighten to dislodge any dirt that might be there.

If it still leaks, replace the core. Unscrewing the core right out will let all the air out, and coincidentally clean the seat that the “springy thingy” seals on. To do this, you need a slotted metal valve cap, or a valve tool, and a kindly service station operator to assist if needed.

The metal clamp-in valves are different. These are used in some alloy wheels, where the thickness of the metal around the hole is too great for a snap-in type. But they are even more desirable when high speeds are the norm. Unlike a snap-in, they do not flex, and they sandwich two air seal washers under compression to get the air seal. So even though they cost more, they last longer, because it is not as necessary to replace them after every tyre life.

Want to know more? See our “All about tyres” section or our “Inflating Tyres Safely” post.

Tyre Supplier Wanted for F1

Tenders are invited for supply of tyres to high tech automotive company.

Previous inscrutable supplier of past 13 years, exclusive supplier past three, willing to pass on tales of heartaches and drama to successful tenderer at the conclusion of the 2010 season.

Apply – if you’re rich, resourceful, and only slightly demented – to:

Bernie Egglestone PLC -F1 cars Division

(Bridgestone Firestone have announced that they are relinquishing their role as the only tyre supplier to Formula 1 Racing at the end of the 2010 season.)

P.S. The ad is a spoof.

Good Tyres, Bad Tyres, What’s the Difference anyway?

Because so much of the detail of a tyre is hidden from view, and it doesn’t mean much to the average tyre buyer anyway, the customer feels quite entitled to ask “Why does this tyre cost more than that tyre, and what does the difference mean to me anyway?”

Because more often than not, the tyre is presented in a vertical stack alongside other tyres, the salesperson is quite likely to launch into a comparison of tread and buttress design and width, tread pattern design, accompanied by claims of superior mileage, roadholding, reliability, and “it’s on special this week only” sales presentation. The reason is that either the customer can see these things for themselves, or can conceptualise, or are prepared to accept because the salesman obviously knows more than they do.

The question remains though – “why does this tyre cost more than that tyre?” It’s a valid question from the customer’s point of view. Why do some tyres cost more than others, and is it worth it to buy the more expensive tyre?

So start with “how recent is the design?” Most new tyre designs (sizes, patterns, constructions) are brought into production to meet the requirements of the design engineers of new cars. If they didn’t ask for particular improved tyre attributes, then the design process would stagnate. They drive the improvements, to meet design parameters that they want to incorporate in their new car design. This process goes on worldwide, all the time.

The tyre company, needing their business, designs, qualifies, tests extensively, government certifies their new tyre design, and submit prototypes to the car company for evaluation on their new design car. To this stage, this has cost a great deal of money in technical resources, tooling costs, mould manufacture, and qualifying testing. Then they wait while the car company engineers evaluate their tyres against others from competing tyre companies. So there is no certainty that these prototype tyres will ever see enough of a production run to amortise their development costs.

Remember, each new car has at least 4 new tyres, possibly 5.

So hurrah, at last the car company accepts the tyre for production, and contracts for supply at a particular rate at 12 hour’s notice is arranged, at a price that is barely adequate.

Then, after two to three years, replacement tyres are required by the car buyer from a retail tyre store, in competition with tyres from all over the world in the same size. This is possible because of currency alignments, and because tyres are all made to conform to the same standards regarding size dimensions, speed and load carrying capacity.

But there emerge major differences in appearance, because the car engineers may have specified a quiet riding tyre for a saloon, whereas more eye-appealing tyres from say Europe in the same size may have been designed for a more sporty vehicle; or advertising campaigns, consumer reviews may influence both retailer and buyer; the reputation of the brand definitely carries weight; word of mouth approval; bulk package deals from wholesaler to the retailer; or simply the skill of the salesman in influencing the customer’s choice, based on questioning the customer as to the application of the tyre. Always in the background, is the appeal of low price.

Another 3 years on, another 60000 kilometres, time’s moved on, probably the car’s changed hands, the pattern is no longer available (the moulds do wear out), fashion has changed, tooling costs have been recovered, so the price of the product has been lowered to meet competition and retain market share. Besides, 18 inch wheels have superseded 15 inch- that wasn’t so long ago, was it! Your once newly developed tyre has now become the price leader into the tyre shop so that hopefully you will buy something better, more modern, better performing, more costly.

Tyres are all fat and black, look the same from the outside, they’re almost all truly round these days, and the detail of the construction differences are inside the casing. However, small differences inside add up to small improvements in braking, handling, cornering, steering response (lane changing ability), quietness, and harshness over concrete road joins, durability under high speed/high load conditions, and other measurable improvements. All carry a cost, improvements are small, but when it comes to the crunch, may make a difference to your comfort or wellbeing. Just the design of the tread pattern, the scrambling of the tread elements to break up the noise generated, can add considerably to the cost of the mould. Then you have to have the I.T. expertise to be able to produce the noises the pattern makes on a computer first.

If you buy a bad tyre, it will be with you for a long time.

Tread life isn’t the be all and end all. A survey of Australian motorists some years ago showed that the quality most desired in a tyre was the ability to stop, and handle, in the wet. Perhaps the average motorist is more discerning than they are given credit for!

If you would like to know more, have a look at the blog on www.carbonblack.com.au, and the “All About Tyres” section too.

Goodyear Wingfoot teams with Aussie Lightfoots

Helen and John Taylor, an Australian couple who have made a speciality of setting records for low fuel consumption in the USA, have done it again.

Converting their miles per American gallon to litres per hundred kilometres yields an astonishing 4.155 litres /100 km in their 2009 Volkswagen Jetta diesel.
This time they were riding on Goodyear Fuel Max tyres, and improved on their 2008 figure by a further 15.4%!

This consumption is more fuel-efficient than the most popular hybrid, and shows what can be done with modern diesel technology, careful preparation and fuel saving driving techniques.

Follow this link to learn more.

So how do they do it? Tyres obviously play a part, since Goodyear sponsored their 9000 mile circuit of the States. We are constantly told to maintain high air pressures if fuel savings are desired, but what are the limits? A tyre usually absorbs around 2 KW just rolling around under load at 120 km/h.

The safe maximum pressure of a tyre is shown on the sidewall, and for a passenger tyre is in the 36 (Standard Load)- 42 (Extra Load) p.s.i. range. It will not burst at 43 p.s.i., but a maximum is specified to maintain a margin of safety for tyre abuse such as potholes and rough edges. So economy drivers go to the limit, or beyond. A tyre with 15 p.s.i. pressure pulls nearly twice the rolling resistance as the same tyre at 33 p.s.i. at 120 km/h, the higher pressure giving a fuel consumption improvement of about 4%. Steel belt radials have the lowest rolling resistance, too.

Staying with tyre design, a narrow tread width, shallow tread pattern, and a rounded tread arc radius all contribute to lower rolling resistance, and with specially compounded tread rubber it is possible to design a tyre to maximise the reduction in a tyre’s contribution to fuel consumption.

Preparation of the vehicle using low friction lubricants, a well run-in engine, diesel fuel designed to give “more bang for the buck”, and other tricks of the trade are also used, such as refuelling at low ambient temperatures, like the middle of the night.

But driver’s skills are required to get good figures. Feather-footing, low top speeds, shift points carefully calibrated, travelling when wind speeds are low, smooth car surface with no unnecessary projections, climbing hills carefully (just making it over the top), and no air-conditioning are techniques used. Depending on the rules of the contest, in most cases coasting downhill, and drafting, is prohibited. In certified fuel economy runs conducted in Australia, an independent observer travels in the car to prevent this.

Want to know more on the tyre angle? In our All About Tyres section you will find Green Tyres are Black, David’s ten tyre tips, and Exploding Cylinders which will expand on rolling resistance and fuel consumption.

Brad Pitt falls off his Chopper

So Brad Pitt fell off his “chopper” motorcycle. Unfortunately for him as he was in view of the paparazzi.

Hasn’t anyone told him that motorcycles with very high castor angles on the front forks (laid back at an acute angle) have very poor stability at low speeds.

They fall over.

That’s why BMX bicycles and trail bikes have their front forks ALMOST vertical, so they can be manoeuvred at low speeds. If they are vertical, then steering at high speeds becomes very twitchy.

In contrast, high castor angles steer very much in a straight line at higher speeds. Think Peter Fonda (who? say the younger generation) and his “Easy Rider” motor bicycle. Man, was that laid back.

That’s why shopping trolley front wheels always have a small, but positive castor angle on the steering wheels. Otherwise they just jiggle from side to side, and are a pain. Hence why Brad felt!

Your car’s “alignment” incorporates all of the above to keep you safe and in control, and hopefully without the paparazzi.

Wire Failure – from Ipods to Tyres

FAILURE – not a pretty word is it? Yet I had two failures this week, both due to FATIGUE.

My steam iron cord failed just where it comes out of the rubber tube at the end of the handle, and my I-pod just where the ear bud cord comes out of the plastic.

Why there? The iron had a long rubber tube, and a spring shaped thingy as well wound around it. Yet it still “failed” there. The wires inside were charred, but very fine. The I-pod wires were just fine, and broken, if you get my drift.

Why do they make them out of such fine wire, you were going to ask. Well if they made these flexible leads out of a thicker wire, they would not last long at all. Witness when you want to bend a coat-hanger till it breaks. It doesn’t take long, and it gets quite hot to hold where you’re bending it.

But like the iron and the I-pod, it will always break first where it is being flexed the most. This needs a bit of explanation.

So it is with tyres. If nothing else destroys it, such as road damage, the tyre will fail where it flexes the most. Wrong! It fails first where the greatest differences between flexibility (the tyre sidewall) and rigidity (the bead/lower sidewall); or upper sidewall to tread and belt area exists. It fails due to fatigue because by then, it will have rotated and flexed at these parts of the tyre, on average 30 to 45 million times for a passenger tyre, and 100 to 130 million times for a truck tyre.  Truck tyres go further because they’re inflated harder, so don’t flex as much, though they may have worn out three tread lives by then- tyre speak for been retreaded twice.

After that, the carcass of the tyre is not worth retreading because it is approaching the unreliable stage due to fatigue. Reliability is highly prized- and highly priced you might say.

Passenger tyres go at least twice as far as they used to 30 years ago, so a large chunk of the fatigue life built into the tyre is consumed in the first tread life. This is why retreading of passenger tyres has declined to such an extent. It is also why the motorist should look after his tyre pressures. The flatter or more overloaded the tyre, the more the tyre deflects as it rotates, and eats into its reserves against the ultimate failure- fatigue.

Incidentally, the wires in the steel belts of tyres are cables of wire made up if strands of fine wire, just like in the steam iron. The wires in the bead, which locks the tyre on the rim, don’t flex, so they are more like a coathanger wire. The iron had lasted quite well really- at least the fatigue beat the corrosion inside the steam chamber!

Here’s the plug! Stuckey Tyre Service

Stuckey Tyre Service is one of Australia’s premier suppliers of car tyres, whether for vintage or motorsport application, or everyday road use. We supply all the major premium tyres. Our sales office and warehouse are located at 828 Sydney Road Brunswick, Australia.

Servicing the demands of Australia’s leading motor racing teams has provided us with unrivalled knowledge of the best performance tyre and wheel combination for every application, road or track. From the most exotic European sports car to the average family sedan, we at Stuckey Tyre Service have a carefully selected range of tyres and alloy wheels to enhance the road performance, safety and appearance of your car.

At Stuckey Tyre Service you can take advantage of the ultimate precision fitting and balancing service where the utmost care is taken with your valuable tyre and wheel purchase. In particular we take great pride in being able to balance a wide variety of specialty wheels including wire wheels for historic applications. The most advanced fitting and balancing equipment is used by skilled technicians whose work is trusted by Australia’s top race drivers at speeds over 300Kpm.

We at CarbonBlack love sending customers to the Stuckey team.

For the Techies – How Hard is Rubber?

Natural rubber is the sap of a rubber tree, converted to a solid by coagulating it with acetic acid. Rubber used in tyres is generally the product of an oil refinery.

When combined with chemicals such as carbon black, antioxidants, and hosts more, sulphur added, the mixture subjected to heat and pressure, it comes out vulcanised. Sulphur makes the process irreversible.

Part of the “black art’ of making up the various mixtures used in the many components of a tyre, is varying the “hardness” of the rubber compound. For example, the rubber around the bead wire is compounded up to be quite ‘hard’ since it doesn’t move when the tyre rolls along. Conversely, the sidewall is ‘soft’, because it moves around a lot- it flexes.

However, most attention is paid to the tread compound, because this affects the wear and grip of the tyre because it’s the only part that hits the road.

How is it measured?

The tool used in the trade is a Shore A Hardness Durometer. Never heard of it? There is a range of them, designed to measure the hardness of different materials.

It simply is a small hand held tool with a domed plunger that is pressed into the surface of the rubber. The reading obtained on the quadrant scale when the needle is first pressed squarely against the rubber, is the hardness. Some cautions though- rubber hardness varies with temperature, it softens as it gets hot- every race car driver knows that. Also, the rubber ‘creeps’ away from the plunger, and as you hold the plunger against the tyre, the initial reading falls away.

So that is absolutely no help when the salesman tells you that the tread of the tyre that he’s selling is hard and long wearing. You might get a clue by pressing a reasonably blunt pencil into the rubber. If the rubber is “soft” the indentation might stay around a while after you remove the pencil. If it’s “hard”, the indentation might disappear quicker than for a softer rubber.

That’s not much help either, is it?

This is because there are many variations on a theme to make a tread compound. But beware of the salesman who tries to tell you that the tread is long wearing, and hard, and gives good grip, particularly in the wet. That’s nirvana, and hasn’t been achieved yet, to my knowledge.

So treads and sidewalls might have 1-2% sulphur, bead wire compounds 6% sulphur, and the old fashioned black ebonite ruler that granddad had, contained 35% sulphur, and was as hard as the hobs of hell.

I did say that it was a “black art”!

CarbonBlack TyreXchange on A Current Affair

Thanks for those of you who continue to promote CarbonBlack to your friends and to the media!

Last month A Current Affair on channel 9 covered the CarbonBlack’s tyre research and tyre dealer directory. It was all about looking for new tyres and the fact that only few people knew about their tyres. ACA had done an interesting  study showing that the less informed you are the more money you could possibly pay for your tyres.

Then, the show explained how you could research tyres and compare tyre dealers on CarbonBlack.

This is the main reason why tyre dealers join CarbonBlack:

CarbonBlack tyre dealers offer the right price and the right service. They are reputable dealers whose purpose is to satisfy customers rather than to sell by any means. That’s why our dealers accept to share information and to be reviewed on CarbonBlack by their customers. They understand today’s role of social networking as the most effective way to market, and that a longer term customer is worth more than a one-off over-paying one.

Tyre Buyers: On the old subject of price, remember to always compare apples to apples, or tread to tread. When replacing your tyres you get what you pay for.

• Know what you’re after: safety, performance or cost savings – you will not get all three in one tyre
• Do your research on the tyre dealer. Read reviews (eg. on CarbonBlack)
• Ask questions. Be sure you understand what you’re buying.

An informed customer is an empowered one.

The whole segment on CarbonBlack is available in the link below.

http://aca.ninemsn.com.au/article.aspx?id=860857