Archive for February, 2011

The Pope and the Little Girl

She’d been kissed by the Pope!
Then this little girl got run over by a reversing vehicle.
She lived! The power of prayer!

Couldn’t possibly have had anything to do with the fact that the reversing vehicle had DUAL rear wheels, could it? And that the contact pressure of the weight of the vehicle was spread over twice the area, and so was markedly less than if it had been a single wheel. Could it?

And that if the contact area of the vehicle is large enough, then even a heavy vehicle can run over soft sand- like an army tank, or a 4WD with its tyres let down to increase the area of the tyre footprint. Could it?

One for the believers!

February 22, 2011 at 11:44 pm Leave a comment

PROLIFERATION IS THE NAME OF THE GAME

Some nostalgia in this episode, but bear with me, I’ll get to the point later!

The title comes from an old Bobby Darin song called “Multiplication is the name of the game”, and he wasn’t singing about tyres either.

Nowadays, as far as your local tyre service is concerned, it’s “proliferation of the range of tyre sizes” sold on the Australian market. Were things simpler in the old days? Just read on.

30 years ago, Australians drove Holdens, Falcons, and Chrysler Valiants in numbers. If not them, the deluxe versions Premiers, Fairmonts, and Regals. Around 30 different car models were available.

Today, it’s over 300 models sold on the relatively small, and now fragmented, Australian market.

Should I mention the Leyland P76? Of course, because it illustrates a very important point- that “FASHION RULES”. Besides altering the very neat Italian designed lines of the car to increase the boot (trunk) size- supposedly to accommodate a 44 gallon drum –like why would you want to? the P76 illustrated the influence that stylists have on a car’s appearance.

Just weeks before the launch, the car was shown to the salesmen who were to sell it. They were horrified. “We can’t sell that- the wheels and tyres are too skinny” they said. So seven weeks prior to launch, an upgrade in the width of tyre and wheel equipment was decreed, leaving suppliers of both scrambling to produce them in time.

So the P76 joined the big three in the choice of tyres. 60% of our production at the time was in the 6.95-14 tyre size, and around 15% in the 7.35-14 tyre size. All were cross ply, radials were just coming on-stream. 6.95 was the tyre width in inches- equivalent to a 175 mm wide tyre today (which is “skinny”)

Life was simple then- or was it?

The rub was that the conservative motorist wouldn’t accept the new fangled tubeless tyre- which, let’s face it, weren’t as reliable as they are today- they used to get bubbles under the tread. So we had to make both types. Would you believe, our company (Olympic Tyres) made 84 different 6.95-14 tyres. Listing them from memory, first the tread patterns;- highway, lug, wintertread, town and Country; and the sidewalls with black, full white on one side, triple rings of white, red striped, triple red striped. (Incidentally, the red striped Reflex Radials are highly prized by owners of authentic 351 G.T. Falcons, which bring astronomical prices). The tyres could also be had in either 4 ply or 6 ply rating! That’s just from memory- there had to be others.

That then was an inventory problem.

That’s the nostalgia bit. How does this relate to the modern tyre service confronted with a car model and tyre size he may not have seen before. His first question is “Why do they do it?”

Engineers design cars. The tyre and wheel equipment are an integral part of the suspension, which can be tuned to give the desired ride, handling, vibration periods, harshness, all the while being compatible with the A.B.S. braking system, traction control, and stability control computer based systems, all of which are useless if the tyre doesn’t grip.

So dependent on the model of a particular vehicle design, whether aimed at the sporting motorist, family motorist, boy racer, fuel miser, one of the easy variations is to change the wheel and tyre package. Note- it’s a package. A lighter mag wheel will affect the spring rate, for example, and also run true because it’s a machining, not an assembly of pressings.

Also, some tyre companies have interlocking ownerships with car companies, which aids in reducing development times, we are told. Naturally, there is some bias in the choice of tyre design as a result.

But fashion still rules. Salesmen like selling cars that look bold and spunky, with the wheel wells filled with big diameter mags and wide spunky tyres. The P76 has a lot to answer for!

The effect on your tyre service has been that they realise that they cannot stock a fully representative range of tyres. This transfers the load back to the distribution network of the tyre importer. Rarely is the car distributor of much help at all. So importers have a large central warehouse, with a regional network to back it up. This fundamentally is inefficient. Distributors would love to ship tyres in pallet loads using modern bulk handling equipment direct to your tyre service. But today, this is difficult and impractical.

So what this boils down to, is a delay while your exotic tyre is shipped out from a warehouse that may be three days away, as far as the distribution set up is concerned.

So you have to fall back on running on your spare- if you’ve got one!

February 17, 2011 at 10:57 pm Leave a comment

WHAT IS RUBBER ANYWAY?

The easy answer is that it is the sap of a tree.

However, this hides the true romance of the discovery of rubber and its useful properties, such that the whole world now moves on rubber.

So let’s delve into history a bit.

The 15th century Spanish explorers ( read “conquerors”) of South America discovered that the natives (South American “Indians”) had dried the juice of a tree (hevea brasiliensis), rolling the resulting strips into a shape resembling a modern football, and kicking it about (barefoot of course), thereby laying the foundation for a whole lot of games which involved grown men kicking a rubber ball about.

For which they should be censured, no doubt.

The early explorers brought some of this material, called in those days “cauchouc”, back to Europe, where the scientific minds of the day couldn’t find a use for it, other than as an eraser for pencil marks, and as a bouncing ball curiosity.

Eventually other uses for it began to develop, amongst which were waterproofing of clothing (Macintoshes), but it was still a curiosity.

Then someone smuggled some small specimens of the tree, and some seeds, to the Kew Gardens in London, where they were propagated. At about that time, the use of rubber expanded dramatically, when John Boyd Dunlop invented the pneumatic tyre (1888).

Enterprising souls decided that the Malay Peninsula, then a British colony, would make a good spot to establish rubber plantations, and establishment of these occurred at a rapid pace, continuing on well past the middle of the 20th century.

When control of these was lost to the Japanese Army in 1940, it started a huge program to replace rubber with a synthetic replacement. Concurrently Germany was doing all it could to take over the only synthetic rubber sources in Romania, because of the strategic importance of rubber to a modern mechanised army.

Eventually the U.S.A. with a program second only in size to the development of the atomic bomb, developed a usable synthetic rubber which could be used on existing rubber processing equipment.

Its use continues today.

During the seventies, many rubber plantations ripped out their trees to replace them with palm oil production. Natural rubber prices are now at an all time high, due to flooded plantations, demand from China and India. I bet they wish they hadn’t!

February 7, 2011 at 2:18 am 1 comment

World Tyre Production Shifts Camp

You could be forgiven for thinking that tyre production is all shifting camp to China. Not so.

Chinese tyre production is booming. Production last year was up 30%, but because of skyrocketing rubber costs, profits were up only 20%. Fujian Province exported 32.85 million tyres in 2010, an increase of 27%. Kumho sales increased 34% in one year. It is believed that there are 30 tyre manufacturers in China already, so we can expect to see some entirely new brands sold in Australia in future.

However, expansion plans are the go, but not necessarily in China. Hankook, a brand familiar to Australians, is building three new plants- one in Indonesia, one in South Korea, one in China. These will boost total production to 100 million (one billion) tyres a year by 2014.

Cheng Shin, Maxxis tyre brand, is also building three- 2 in China, one in Taiwan, to boost capacity to around 59 million tyres a year.

Double Coin, also known in Australia, is to build a new plant at Hefei, China. Formerly in bed with Michelin, the partnership terminated in 2009, now it looks as though it might be “on again”.

However, if you’re interested in importing some tyres, you’ll have to wait till after the Chinese New Year (the Year of the Rabbit), as they are ALL on holidays 28 January till February 14th.

The sleeping giant, India, cannot be ignored either. Apollo Tyres took over the Dutch brand Vredestein, in 2009. Having digested that, Apollo are now expanding their Limbda factory to capture exports to Bangladesh and other near neighbours. JK Tyre are doing likewise to expand to 1.4 million tyres a year.

The other side of the coin is closure of factories elsewhere in the world. For example,Maine Industrial Tyres (U.S.A.) closed their Gorham factory, and relocated to, where else but, China.

February 7, 2011 at 2:16 am 1 comment

Formula 1 Tyre Rules Change Again

Just a few weeks now till the opening of the new F1 season. Tyre equipment has changed to Pirelli from Bridgestone. Pirelli have finished their testing of development tyres at Abu Dhabi, using a 2009 Toyota F1 car as their test bed.

Then along came the “rule changers”.

This year the number of sets of dry weather tyres that can be used over a weekend of qualifying and racing has been reduced from 14 sets to 11. One complete set (4 tyres) has to be handed back before the start of the weekend’s second practice session, and two sets before the third practice.

Not only that, but the top ten qualifiers have to start on the same tyres as were used when setting their qualifying time.

This approach is aimed at having the team managers have a good look at their strategies, as some teams may opt to set slower practice times in order to have optimum tyre equipment for the actual race conditions.

Need more background information? Then have a look at “Tread Compounds for Formula 1”, and a heartfelt plea for the hair tearing stages that team managers already go through to choose the right tyre for the conditions, earlier in the “The Tyre Blog”.

February 4, 2011 at 3:10 am Leave a comment

GIANT TYRES

It’s almost a cliche- the photo of a giant tyre dwarfing the man standing beside it, at some remote mining site somewhere in Western Australia. They always seem to populate the financial pages, and mining magazines.

They’re big alright- the wheels are large enough to accommodate the electric drive motors in the hubs- a 52 inch wheel rim is small fry. The dump trucks can carry loads over 250 ton, and they’re not exactly light themselves. All this is carried by 6 giant tyres.

They are shipped into the country in empty ore carriers from overseas, generally Japan. However, due to the mining boom, there is a worldwide shortage, and relatively few manufacturers tooled up to produce these tyres for use on extraordinarily large and expensive equipment.

The tyres are expensive, but downtime on the machines they equip is even more so. So mining sites maintain their haul roads in excellent condition, so that rocks or spoil cannot damage the tyres.

Thirty years ago, retreading these tyres was practised extensively, but eventually died out because of the economics of transporting them to a central factory and return, when the new tyres were delivered practically on the doorstep of the mines.

However, due to the shortage of tyres, and the skyrocketing cost of natural rubber, the economics of retreading (sometimes called relugging) are being examined again.

Rebuilding the tyres involves removing what is left of the old tread, preparing a surface to which new rubber will bond, applying new rubber, and sculpting it to a tread design compatible with the original tread. For this, massive machinery is required, so the investment is not undertaken lightly.

30 or more years ago, lugs of rubber prepared with a sticky base were heated, and hammered onto the prepared surface. Rebuilding a tyre could take two days by this method. The system has been mechanised to some extent. A continuous strip of hot sticky rubber is spirally wrapped around the tyre to a controlled profile. The result looks like “corrugated rubber”, and at this stage has no tread pattern.

A tread pattern-cutting machine, massively strong, is then used to cut out the surplus rubber between the tread lugs. This excess can then be used again, representing quite a saving in material.

Finally, the rebuilt tyre is loaded into a giant autoclave, bigger in diameter than the rebuilt tyre.
When I left the industry in 1989, these were 130 inches in diameter, 12 feet deep, and required a very large steam boiler and air compressor to fill them, taking three tyres at a time. Curing time was in the order of 14-16 hours. Vulcanisation was completed over 24 hours as the tyre cooled down. In fact, the internal tyre temperature continued to climb as the tyre was removed from the autoclave.

These tyres are BIG! 33.00 x 52 was the biggest 30 years ago. Bet they are bigger now!

In terms of conservation of resources, retreading these tyres makes sense. After all there are only so many ways that discarded giant tyres can be used to define a farm front gate, line a mining road, or impress a tyre service’s customers. Reliability of performance is still the prime requisite as far as the mines are concerned. It only requires one lug to fall off, or get torn off, and the machine is out of action.

One of my earliest memories of these tyres was at the bottom of the Avon Gorge in W.A., where a deep gorge was being cut to accommodate the then new Trans Continental railway. The gorge was so deep that at 2 o’clock in the afternoon, it was dark at the bottom at the work site. The Euclid scrapers had experimental Michelin Radial tyres on them, the tyres having been developed for use in the Sahara desert. When empty, the scrapers used to charge back at 30 m.p.h. with the driver hanging on for dear life, firmly belted to his seat, clad only in shorts and work boots, as the contrivance bucked and kangarooed along the haul road. That’s when I learnt that the tyres were the whole of the suspension system.

Another experience was at Dampier, W.A., when the salt mine there wanted to shift 12 million tons of salt in a hurry, away from the adjacent iron ore stockpile. Triple trucks (i.e. one more trailer than a double, weighing 101 tonne empty, (aluminium) were loaded with 160 tonne of salt, carried it 10 kilometres, dumped, and returned empty. Tyre size involved was a comparatively small 14.00-24, but the problem was that it was 52 degrees, and the tyres never had a chance to cool down. So the haul speed had to be restricted, and this cost money. So did blown tyres! At 68 km/h the tyres performed O.K., at 73 km/h they became unreliable. Quite a lesson there in “make haste, less speed”.

February 1, 2011 at 2:32 am Leave a comment