A lot of good 'skull sweat' has gone into the rubber under your car and when it comes to complexity, most people probably wouldn't put tires very high on the list. After all, they look pretty simple, don't they?

True, but this apparent simplicity is deceptive. A modern tire is actually a very complex piece of equipment, consisting of many different components. You can't see many of these but without them your tires simply wouldn't work.

Let's take a look at how the most common type of tire, radials, are constructed.

The first step is assembling raw materials. Raw rubber and various chemicals are an obvious starting point, but modern tire manufacturing uses a lot of things you wouldn't expect to find, such as pigments, wire, and special fabrics.

Tire manufacturers today use many kinds of rubber, both natural and synthetic. Some counts place the different kinds of rubber used in radial tire construction as high as 30. No matter what kind of rubber is used, the manufacturer will add other materials to get the compound they want. These can include antioxidants, oils, carbon black and numerous other additives depending on the type of tire being made and the manufacturer.

Once the raw materials are assembled, they are mixed together in Banbury machines. These are extremely impressive pieces of machinery that look sort of like God's blender, assuming God wanted his smoothies subjected to intense heat and pressure.

After the Banbury machines have had their way with the rubber compound, it is repeatedly milled by putting it through rollers again and again. After the rubber is milled, it is ready to be formed into sidewalls, treads and other parts. But before they are put to use, the interior of the tire is assembled on a tire building machine.

The first part of the interior is called a bead or bead bundle. This is a hoop shaped length of rubber coated steel cable. The bead fits against the wheel rim and gives the tire the strength to stay seated on the wheel rim.

Next, a double layer of rubber (a synthetic in this case) is added that seals in air. It is this "inner liner" that allows modern tires to be tubeless.

Two layers of rubber coated fabric, the cords, are placed over the inner liner. Synthetic fabrics are commonly used as cords, including polyester, rayon, and nylon. The most common fabric in use today for this purpose is polyester.

The machine then shapes the radials into something very close to their final dimension. This is done to make sure all the parts are in the right position. Next, steel belts are added. These help to hold the tread on the road surface and make the tire more puncture resistant.

The last part to be added is the tread. Rollers press all the parts firmly together, and what we are left with is a tire that looks pretty close to what will go on our car.

However, this "green tire" is not ready yet. For one thing, it needs to be cured. For another, it is as bald as a cue ball.

At this point another reject from God's Kitchen comes into play. The curing press, which looks similar to a giant waffle iron, gives the final shape to the tire, imprints a tread pattern and vulcanizes the rubber.

Although the tire is now fully constructed, it must still go through one more stage in the manufacturing process, that of inspection. Tire manufacturers use both human inspectors and special machines for different parts of the inspection. Some tires are even X-Rayed to check for internal flaws. Others are randomly selected from the production run to be ripped apart and/or tested to destruction in order to look at every aspect of the tire that could affect safety or performance.

Although they look simple on the outside, a modern automobile tire is truly a masterpiece of engineering. Now that you know how they are made, chances are you will never take your tires for granted again.