Why are tires so important? Well, look at your car, at tell me which part of it touches the tarmac. Right, just the tires. It’s the tires that grip the road and this grip allows us to accelerate, slow down, turn sideways, dampen bumps, etc. Many people look after their brakes, but in action it’s not the brakes that stop the car (just like it’s not the steering that turns the car), it’s the tires. Go improve your braking system: Fit a bigger master cylinder, sturdier pipes, bigger rotors, discs and more grippy pads. How much feet of stopping distance will you earn? Nothing! Why? Because your tires stop the car and they can only apply so much of a stopping force. Put better tires on the car, and watch the stopping distance shorten by dozens of precents!
So, driving without good tires is much like driving without good brakes. Would you drive without good brakes? No, right? Than don’t drive with faulty or badly inflated tires! Tires are also quite cheap (in spite of a certain increase of costs due to the latest oil crysis) relative to their contribution to both performance and safety, so there’s no room for compromise. To have a better understanding, take two sheets of paper, and push them under both sides of the tires, front and back, untill they meet resistance that stops you from pushing them further. Look at the gap that is left between the two sheets: This is the whole size of the tires’ contact patch that actually touches the ground, and don’t be surprised if it’s no bigger than your shoe. The fate of your life sits on four size-9 shoes!
Estimations in Western states consider about 12% of the collisions, mostly harsh ones. This does not include collisions where tires had a significant contribution where people that stopped after their tires broke down, had been run down on the roadside, and in situations where a lost of control (categorized as sliding, swerving, lost of control or speeding accidents) would have been prevented by better tires, and in situations where good and carefully inflated tires would have stopped the car earlier before an obstacle or reduce the contact speed to a minimum.
The invention of Pneumatic tires is attributed to one Robert William Thomson, but they were only applied in action by John Dunlp on bicycles in 1986. The Tire became removable not five years later, and tubless tires were introduced in 1903; five years later tires became treaded and in 1910 they turned into the black round tires we know today. Of course the tire industry has made a great progress in constant development of new technologies like regroovable truck tires, recycled tires (which are still not very efficient in terms of road grip) and other developments. A new tire is ten times as durable as those that were used thirty years past, although this rigidity made the tires less resistent to aging which is caused by the atmosphere.
The modern tire industy is also a succesfull economy. It is the main buyer of rubber, which is being purchased at Malaysia, Indonesia and even in parts of Africa (after world war two), where woods of ‘Haveae’ trees were planted. These trees, once matured, are bleeded by a spiral cut that protrudes their outside layer, causing them to bleed their elastic sap into bowls. By heating it with a mixture of acids it turns into rubber of various qualities.
Synthetic rubber (made of crude oil, charcolan and Acetylene) has turned more and more popular, especially in light cars, first as an economic move of the great tire and rubber buyers of America and Europe, which sought to reduce their dependency on the far-eastern countries (along with growing heavae trees in the british colonies of west Africa). Today, both the synthetic and natural rubber are made in the far east. Modern tire industries include over 100 manufacturers and one billion tires sold per year, with over 20 billion dollars made annually. Be worn, though, that the amount of cheap and low-quality tires is about equall to that of good tires.
Tire factories are a highly occupied industy, with many professional secrets. The development of a certain tire brand, even a simple road tire, costs hundreds of thousands and millions of dollars. The industy is based on far-eastern rubber, natural and synthetic, which is being sewn into layers. The grey color of the rubber is turned black by use of soot which increases the tires’ radiation and heat resistance in a low cost, and by applying many chemical agents, such as anti-oxidants and anti-ozonenats. These “Plies” are than extruded with the other plies of polyester and steel. The tire is than sulphated and packed with sylicon before being shifted to the market.
Old tires were made in a diagonal shape: One ply was set diagonally relative to the next. These “bias-ply” tires had many disadvatages: They worked as one unit in dampening road bumps and dispersing heat. They were very vulnrable to under-inflation, heat buildup at high speeds (at 60mph, an average road tires rotates almost 1000 times per minute), and to punctures: The tires had in internal tube with air, which, once punctured, would allow the air to leak quickely from the point of connection between the tire and rim.
Modern tires are Radial: They have a thin sidewall which is seperated from the thicker tread. The tires are also steel-belted (for structural rigidity) and “Tubeless” which means that the air is being fed directly into the tire. This technology reduces the speed in which air is bled during a puncture. Fitting a tube into such a tire is dangerous.
Tires are divided into groups:
1. Standard Road Tires: Including high-performance tires (marked as such).
2. All-Season Tires: Marked by M/S for “Mud and Snow.” These tires give a good compromise between dry road grip and grip on thin, loose snow or mud in the winter.
3. All-Terrain Tires: General purpose off-road tires, including a sub-division for sand-dune tires
4. Mud-Terrain Tires: Aggressive off-road tires for driving in mud.
5. Snow tires: Used for snowy and icy conditions.
6. Ice Tires: Studded tires for hard ice.
7. DOT-Racing Tires: Racing tires (soft rubber compound and shallow tread) which are street legal.
8. Racing Slicks: Racing-purpose tires used in professional leagues, with no tread or with a shallow tread (semi-slick).
9. All-steel tires: Used in heavy vehicles like trucks.
10. Bike tires: including road tires, performance tires, terrain tires, etc.
Every category includes various brands and qualities. For the average road driver, the main criteria is to purcahse a tire from a known brand. Unknown tire manufacturers (Like the “Ling-Long” tires that were used in an experiment in Britian) usually make tires that are highly ungrippy and in a serious risk of blowout. The quality of the tire is just as crucial (if not more) than the wear, age or inflation of the tire. New but low-quality tires can be more dangerous than old tires from a good quality.
Tires are rated in what is called a QUTG rating. These specify the tires’ temperature, traction and treadwear ratings, as tested by the US Department Of Transporation (DOT) at the St. Angelo test track at Texas.Temperature specifies the tire’s ability to disperse heat and cope with high temperatures (road tires can reach an internal temperature of 86 degrees celsius!). Most tires have an A rating. B-rated tires can be a satisfactory to people who don’t make long drives on highways or with load. C-rated tires should be avoided. These tires run at 130km/h for 30 minutes before being demolished, while A-rated tires would sustain a speed above 200 km/h!
The traction rating is decieving. It does not imply the tire’s grip levels. It indicates how well it stops on a damp road. It effectivelly illustrates the ability of the tire to drain water and grip a wet road. An AA-rated tire can be worst, on the dry, than some B-rated tires. Still, it’s advised not to go below B. In countries with wet weather, it’s preferable to go for A. The AA rating is new and does not nessecarily indicate a higher quality relative to an A-rated tire.
The Treadwear rating is very important, as it indicates how soft the tread’s rubber is. Softer rubber grips the road better, but wears sooner. Don’t go for below 300. If you don’t drive very much (less than 30,000km per year, as a rule of thumb), go for tires with a relativelly low treadwear, for extra grip. The theory is that at a rating of 100 (The DOT “Standard”, just above DOT-approved racing tires) the tire should sustain 30,000 miles of driving, but this refers to smooth highway driving in ambinet temperatures and not over long durations of time. In practice, the ability to dictate tire tread life based on this data is unrealistic.
An average road tire of about 11kg (with a maximal sway of 0.5%) will be composed like this: 3kg of seven to eight natural rubber compounds, and another 3kg of five synthetic rubber compound; 2.5kg of black carbon; one half of a kilo of steel, and another half kilo for the tire’s heel, and a similar weight for Synthetic fabrics (Rion, Polyester, etc…). 1.5kg of around 40 types (!) of resins, adhesives, pigments, anti-ozonants, anti-oxidants, softeners, Cobalt and other chemicals.
The tire is built over a period of time that usually takes over ten minutes (but in big, automized factories can take as little as three minutes!) and much longer for big tires and racing tires (which are made using special machinary and a lot of manual work). The process begins with mixing the hot rubber with carbon black (a cheap anti-radiant and heat-ressistant substance) and the other chemicals mentioned above, which are than cut into long “mats” of 80 centimeters. The mats are than cut and extruded to create a single tread, sidewall or innerliner. They are than