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.

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!

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”!

Why CarbonBlack?

Our Website is named CarbonBlack- because that’s what tyres are made of – right?

Well, partly – about 35% of a tyre is carbon black.
So what is it? And where does it come from?

As with most things these days “Oil” is the answer, which is one of the reasons why tyres cost so much.

Carbon black USED to be made from burning natural gas in insufficient air, and collecting the smoke that resulted, rich in carbon, on cooled metal surfaces. This was sometimes called “lampblack’, or later “channel black”. The pollution it caused was indescribable, let alone the waste that escaped to the atmosphere.

So another process took over in the early 1950s, called “furnace black”. Oil was burned inside a furnace in insufficient air, and the resulting carbon collected at the outlet. Dependent on the type of oil burned, the design of the furnace, the operating temperature, the flow rates, nozzle design, and any number of variations, it was quickly discovered that the actual properties of the carbon black (still just carbon remember) could be varied.

A whole new family of carbon blacks resulted, from the smallest particle size, intensely black as used in printing inks, to the larger and softer grades used in say motor tubes, which had quite a grey colour, and all the grades in between.

But wait- there’s more, as the Demtel man used to say.

The actual surface of each carbon particle could also be varied, to be extremely absorptive or low absorption. This structure varied the way that the carbon molecules could be intimately mixed into the long chain rubber molecules, which affected the degree of reinforcement imparted to the rubber by the carbon black. This then had a direct affect on the physical properties imparted to the rubber by mixing it with carbon black, such as wear, cut resistance, tensile strength, stiffness (modulus), elasticity, heat build-up under flexing, and a host of other properties.

So the fast developing science of carbon black became dominant in the development of rubber compounds. Without carbon black, tyres would be slippery in the wet, would wear out very quickly (particularly when hot), and generally would not be suitable for today’s automotive uses. That’s just the tread. Other blacks were designed for use in the casing, in the tubeless liner, bead compounds, bead stiffeners, and the many other applications used in a tyre.

The name of our web site pays homage to its importance to the rubber industry.

Terrible stuff to get out of your skin though. I couldn’t wear a white shirt for years!

If tyres burn, why don’t we set them alight and save the planet?

Riots in the streets are nearly always accompanied by stacks of burning tyres defining the no-go zone. They burn very well, although smokily. Once started, they’re almost impossible to put out.

So why aren’t they used more widely as fuel if they burn so well. After all, there is a millions of tyres discarded worldwide every year. They are no good for landfill, because they don’t decompose, and are hard to keep below the surface. In fact, I know of a pile of over 200 million tyres outside L.A. waiting for someone to devise a use for them.

Furnaces to burn them have been developed, and the resulting heat used to raise steam, or for central heating. These take either whole tyres, or shredded tyres, use a conveyor feed system to load the furnace, but somehow haven’t been widely adopted. Someone has to load the conveyor, too!

The reason for non-adoption is possibly “acid rain”. When rubber is vulcanised, it is combined with sulphur. This process cross links the rubber molecules, and converts the rubber material into a stable, three dimensional lattice, which is elastic. The level of sulphur is generally 1 to 2 percent. This level of sulphur is around the same as for high sulphur coal. When burnt, (oxidisation) it becomes sulphur dioxide, and other oxides such as sulphur tri-oxide, dependent on the air/fuel mix. Burn coal, you get carbon dioxide, burn tyres you get sulphur dioxide. High sulphur coals are very much out of favour.

In the atmosphere, these oxides of sulphur combine with water to form sulphuric and sulphurous  acid, which pollutes the air, kills vegetation and our forests which are the lungs of the world.

So a great deal of research into the design of the furnace to minimise these effects and scrub the exhaust gases clean of smoke and pollutants is required, which makes the furnace more expensive.

Then there’s the costs of collecting the old tyres, sorting , classifying, shredding, and the costs of disposal of the ash that results from the burning, though the steel content can be recovered as slag from the furnace grate. However, there awaits big rewards for the designer of a furnace that will be easily portable, has a captive market for its product (heat), and a ready supply of worn out tyres available at preferably no cost.

Revolutions in the tyre industry

Trivia question – two North Carolina residents changed the course of the world in 12 seconds 104 years ago. What were their first names?

Only 2 out of 700 (majority Americans) knew the answer – Orville and Wilbur.

As a result I have a very nice travel clock. Thank you Princess Alaskan Cruises. Took the mind off the 7 metre waves in the Bay of Alaska too!

So after 3 years or so, the Wright Brothers changed from skids to wheels and tyres (tires). These were made by Goodyear.

Goodyear are still a major supplier to the world’s aviation and defence industries, and they celebrate the centenary of the first tyres made specially for aircraft this year.

The Wright brothers chased weight savings assiduously, and Goodyear made special lightweight tyres for them. Aviation designers still are chasing weight reduction and tyre performace. Latest development are tyres for the Gulfstream jet which have an aluminium bead wire core, rather than steel. This saves 1.3 kg per tyre!

Want to know more about Goodyear’s centenary of aviation tyres? Go to  http://motorage.search-autoparts.article/articleDetail.jsp?id=950056

Tyre Tread Compounds

There’s a great deal of confusion amongst car enthusiasts, particularly the “rubber burners”, on tyre tread compounds and their make-up. One enthusiast on a car blog announced that tyres weren’t made from rubber at all, but from oil. You know what- he was mostly right!

Oils ain’t oils, and rubber ain’t rubber any more.

Tyres contain 3 or 4 different rubbery materials. One is natural rubber; which is the juice of a tree, which is coagulated using acetic acid, smoked and dried. The others are all made from oil, and are called “polymers”- another term is “long chain macromolecules” but don’t worry too much about that. It is now possible to make “natural rubber’ from oil too, but it’s cheaper to let the tree do it.

These various rubbers can be mixed together in different ratios in giant blenders to make a compound. At the same time, other important ingredients are added to make the resultant product tougher and stronger. A typical tyre compound may contain 10- 14 ingredients, all added for a specific reason. The most important of these is carbon black, of which there are many types.

A tyre typically has 7 to 11 compounds, each doing a specific job, be it encasing the bead wires, keeping the air in a tubeless tyre, flexing the sidewall, sticking the layers of nylon or polyester together, and so on. But there is only one compound that hits the road where it all happens, and that’s the tread compound.

This is basically the only criterion on which the motorist can judge the performance of the tyre, so it receives the most comment from car enthusiasts. The tyre engineer and chemist can vary the compound formula to maximise/minimise any tyre characteristic that he requires.

A typical passenger tyre tread compound contains as the base polymer styrene-butadiene copolymer, around 35% carbon black to reinforce it, and maybe some silica. These increase the abrasion resistance, tear strength, and cut resistance. Without them, the tyre would go gooey, and wear out very rapidly. Remember those old crepe rubber soled shoes?

Vulcanisation chemicals such as sulphur, zinc oxide, stearic acid, and accelerators make up 3-5%; antioxidants and antiozidants to stop it perishing or cracking, processing aids such as oil, resins, tackifiers to aid in the lay-up of the assembly are all incorporated.

Some tyres have two tread compounds- either side by side (very rare), or a cooler running undertread compound under a harder, hotter running cap stock. Most, however, only have one compound in the tread area.

The rubber used in tyres is normally a copolymer ( mixed and then polymerised together) of 23% styrene, and 77% butadiene. However, this ratio is not set in concrete, and specialty rubbers of different proportions of these two refinery products can be made. For example, “cling rubber”, which was widely touted for its improved wet grip, is 40% styrene, 60% butadiene. The resulting rubber ran hotter, and wore out quickly under Australian conditions. A 90% styrene, 10% butadiene rubber is used to make floor tiles, not car tyres.

Another rubber developed for use in tyres is polybutadiene. Butadiene is the most common feedstock from a refinery. However the resultant polymer suffers one big disadvantage- its wet grip is poor. Its big advantages are however, that it stands up to extreme abrasion much better than other rubbers, and runs cooler. Back in the days when the Armstrong 500 Miler was run at Phillip Island on standard tyres and rims, and the track was not a smooth hot mix like it is today, Harry Firth won the race by changing only one tyre, whilst everyone else changed at least twelve on the very abrasive track. But he lost 3 seconds a lap, because down on the ocean side, the tyres wouldn’t grip to racing levels. The tyres were made from a high proportion of polybutadiene in the tread, specially airfreighted out for the race.

We’re not as skilful as Harry Firth was then, and the Australian motorist puts “grip in the wet” as the top desirable characteristic from his tyres, so its use is now mainly confined to truck tyres in blends with natural rubber, where heat is the main enemy of tyre performance.

So ultimately, it’s the “grip” of the tread compound that drives, steers, and brakes the car, through the contact patch, around the area of a size 12 shoe. It does this by slipping! Sliding generates friction, and this causes things to happen. All tyres slip, particularly driven and steering tyres, which is why they wear out. No friction- no progress. Try driving and steering on black ice sometime to see what I mean.

“Rubber burners” overlay this with “sticky friction” by heating the tread surface till it starts to revert- goes gooey. Lots of smoke! On top of this, tyres generate heat internally from the stresses generated by flexing (the hysteresis loop). As the rubber warms up, the rubber changes its grip characteristics, provided that the compound hasn’t degraded to the gooey stage (“goes off”). This occurs generally in the thickest part of the tyre under the greatest load, like the outside shoulder of a tyre being driven on a banked circuit. That’s why you see tyre technicians who are evaluating tyres, drive a thermocouple needle into the shoulder of the tyre tread- the thickest part. The electric blankets on the wheels ready for a change onto a race car are there for the same reason- so that the car will handle similarly to the old, warmed up tyres.

The position of the white stripes in the tread grooves of the Formula 1 cars indicates the type of compound used in the tread. The tread grooves are there to slow the cars down, even when the road is dry. Race team managers under F1 Rules have to use at least two types of tyre during the course of the race. This adds another source of tactical variation for managers to consider, as though they haven’t got enough on their plate. But the race result may have been decided in a tyre development laboratory in Kobe or Luxemburg or wherever, since so much data has been accumulated on the vagaries of each circuit, and the tyre compound that performs best on that circuit.

It’s almost time for the Melbourne Grand Prix- so enjoy your viewing

Should Tyres have a use-By Date?

Channel 7’s “Today Tonight” program on Friday 5th December, picked up on earlier publicity originating from an American T.V. program “Twenty-twenty”. An aggrieved customer in South Australia complained that he had been sold Light Truck tyres that were already 14 years old when fitted. One tyre had separated its steel belts from the tread ring, causing damage to his mudguard, and raised the risk of an accident.

The British Rubber Manufacturers have recommended that tyres more than six years old should not be sold, but there is no law requiring this anywhere in the world at present. The American Rubber Manufacturers Association states that there is no scientific evidence to support a six-year limitation on the life of a tyre.

The Channel 7 program cut pieces from the sidewall of the tyre, and did a “tensile test”, pulling on the test piece till it broke. Pieces cut from the (used) 14 year old tyre broke at a lower tensile than from a new tyre. Why they tested the sidewalls, which are a different rubber compound to the tread/steel belt area, it is not known, but it is not surprising that testing two tyres made 14 years apart would give different test results. The reason? The tyres were different!

Tyres are warranted for their life by the manufacturer. Occasionally tyres, like many products, are subjected to a recall program. To enable identification of these, a code is branded into the sidewall, which is used world wide, and is a requirement of the American Department of Transportation. It is called the DOT code. Practically all tyre manufacturers worldwide use this code.

The code details the actual factory in which the tyre was made, the design, and among others items, the last appearing group lists the week and year the tyre was made. 3 digits for the ninetees, four digits for the noughties. Examples then are 489 for the 48th week of 1989, 2604 the 26th week of 2004.

Tyres are generally 6 months to 2 years old by the time they are fitted to your car as replacements. The original equipment tyres are generally one week to six months old, dependent on whether the car was made here, or imported.

The Australian tyre market is so fragmented, with many makes and models of vehicles sold, that the supply chain for replacement tyres is very long, and large stocks are held at distribution points to meet market requirements. For example, the 11 hectare distribution centre at Somerton, Victoria, can hold up to 11 million tyres. Naturally, efforts are made through inventory control to ensure quick turnaround of stock going into the store, to reduce holding costs.

Eventually, tyres are shipped out to your local tyre store. Here they should be stored in racks, in a “cool, dry place”. Many tyre storage areas paint their tyre storage area windows with blue paint to screen out U.V. This is because tyres get harder with age. The vulcanisation process continues at a very slow rate, and protective agents such as antioxidants and antiozidants incorporated into the mix diminish in effectiveness with prolonged storage. Walk into a darkened tyre store, and you can smell the rubber. A somewhat doubtful farming practice used to be that tractor tyres were stored by the farmer to “harden them up”, and possibly improve tread wear. Really, all it did was increase the risk of buttress cracking.

Unless stored correctly (read “All About tyres/Storing a tyre” on our www.carbonblack.com.au site), the tyres will eventually craze or crack most severely where the tyre is resting on the pipe rack. This is because stretched rubber is attacked by ozone in the air. Ozone is generated by electric motors and lightning, so maybe the shop compressor is the culprit. However, tests done in the past have never been able to show that tyres stored this way will not give a satisfactory life. The deformations caused by the pipe rack run out as soon as the tyre gets run in on the vehicle- say 10 kilometres, depending on the temperature.

The real sleeper in all this is your spare wheel. Stored in the boot, or under the tray of a light truck, it is subjected to high summer temperatures, and may lay there undisturbed for six years or more if you don’t have to use it. Our discussion on what to do about that is contained in “All about tyres/original equipment”. Basically, it has missed out on six years of design improvements whilst sleeping in the car boot, or lying in the dealer’s racks waiting for a sale, or in the South Australian’s case, 14 years.

So should tyres have a “Use by Date?” It would appear that provided they have been stored correctly, there is not a problem with tyres encountered in the usual course of trade. Besides, somewhere out of Broken Hill or Wilcannia or somewhere like that, you will be pleased to find that the tyre service has your badly needed tyre, even if it is a bit dusty.

All that applies to tyres also applies to automotive car batteries of course, for all the same reasons, except that a lead acid battery does in fact have a finite life, and has to be stored correctly with its charge maintained until it is sold. The warranty period then kicks in once it is sold.

Pirelli Scorpion ATR Named Year’s Best

Pirelli’s Scorpion ATR has been named the best performing All-Terrain tyre by the highly respected Consumer Reports.

Following on from its earlier success in the European summer tyre tests, ConsumerReports.org rated the Scorpion highest among all tyres tested, based primarily on impressive grip in both dry and wet conditions, excellent dry braking and hydroplaning resistance.

The superior performance in the Consumer Repoarts.org test reinforces the German motoring magazine Auto Bild Allrad finding who also determined the Scorpion ATR to be the leader in its class, stating “Pirelli gets the highest average score for off-road tyres’ quality, demonstrating a very good off-road grip, relative low noise, and street performance with good handling characteristics”.

To achieve this result, Pirelli’s engineers focused their attention on the tread design. The biggest challenge was to maintain the durable all-terrain qualities while at the same time achieving low rolling noise levels. The solution was to integrate into the basic design a new concept of “sweeping” curved grooves. With a strong character derived from its aggressive tread pattern, together with various options for sidewall lettering, Scorpion ATR adds much to the personality of the vehicle on which it is mounted, and in true Pirelli style, with unmatched performance.

Three-times Bathurst V8 Supercar champion Craig Lowndes recently fit Pirelli Scorpion ATR tyres to his Ford Ranger and was instantly impressed.

“The quiet-running, symmetric tread pattern makes driving around town a breeze,” Craig said.

“And because of the shoulder and interlocked tread blocks, when I get off the track up at the farm I still have plenty of directional stability, steering response and off-road traction,” he added.

“Apart from the performance aspects of the Scorpion, they look pretty good too!” Craig beamed.

Consumers Union (CU), the publisher of Consumer Reports.org, is an expert, independent, non-profit organisation whose mission is to work for a fair, just, and safe marketplace for all consumers and to empower consumers to protect themselves. The organisation was founded in l936 when advertising first flooded the mass media. Consumers lacked a reliable source of information they could depend on to help them distinguish hype from fact and good products from bad ones. Since then CU has filled that vacuum with a broad range of consumer information. To maintain its independence and impartiality, CU accepts no outside advertising and no free samples and employs several hundred technical experts to buy and test the products its evaluates.