Author Archive

Pirelli F1 “Soft” Tyres.

The Pirelli tyres in their second F1 in Malaysia performed well in 37 degree heat, but it adds interest to know whether they are using the “soft’ tyres or the “hard” tyres. The Yellow PZERO markings are supplemented by a gold band running around the shoulder circumference of the tyre, when the “soft” tyres are in use. These are claimed to give a reduction in lap time of around 1.2 seconds a lap for around 8-10 laps , so they do make a difference, and allow more passing manoevres.

These markings will be used in China too, but will change again for the European season, commencing May in Turkey.


April 14, 2011 at 1:34 am 4 comments


I had an expensive lesson on the destructive effects of ozone on rubber recently.
Ozone occurs naturally in the air, commonly after electrical storms, of which we’ve had a few lately.

But in this case, the destruction originated from an electric motor, immediately under the rubber seal that was supposed to keep the water in my pool’s heating system. What’s that got to do with tyres? Well, when tyres are stored, like on your caravan or on a seasonal piece of farming equipment, care should be taken to protect them from sunlight, and electric motors.

Otherwise, ozone from electric motors will attack the rubber, BUT ONLY WHERE IT IS STRETCHED!
Wide lacy cracks appear, and grow very quickly, as shown in the photo. The victim is shown in the front of the first photo, a new seal in the background. This appearance is typical.

So the temperature sensor was ejected, a geyser of salty water covered everything for 3 metres around, the pumps eventually ran dry, and an expensive repair bill resulted. All this for a 50 cent rubber grommet in the wrong place.

When removed from the pipe, the side of the seal inside the pipe was in A1 condition. This is shown in the second photo- it’s been turned over. There’s no ozone in the water, then- only chlorine.

Another place where this type of cracking occurs is in the bent rubber hoses in your washing machine. That can do a lot of damage too, replacing tiles, carpet, timber, coreboard cupboards, and maybe carpets too.

April 14, 2011 at 12:59 am Leave a comment

Caught Speeding- Blame your tyres!

It took a change of government in N.S.W. apparently, to inject some commonsense into the setting of limits for “overs” on fixed and mobile speed cameras.

The Roads and Traffic Authority had decreed that henceforth the limit would be 2%. The first act of the Minister-Elect was to decree that this wouldn’t happen. The police weighed in with the comment that a thick speedo needle, or fitting a new set of tyres, could cause an error bigger than 2%. You know what- the police were right! Incidentally, in Victoria it’s 2% for fixed cameras, and 3% for mobile cameras. What the basis is for this difference is unknown.

But both police forces admit that there is a “discretionary factor”. This was once explained to me as “the cost of the paperwork and time may make it not worthwhile for them to issue a ticket”.

The reasons for having a tolerance at all are explained in my blog article of September 2007. If the Roads and Traffic Authority staff had read this, they could have saved themselves a lot of embarrassment, and the newspapers a lot of column inches.

One thing though- you can’t change the rolling circumference of a steel-belted radial tyre by varying the tyre pressure (within normal tolerances of course). The steel belts prevent the tyre from expanding. That’s what they are for.

April 14, 2011 at 12:54 am Leave a comment

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


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


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

Older Posts