Have you ever wondered what goes into making a tire? There is a whole lot more to a tire than just rubber and air. Most car tires and light truck tires have a combination of natural and synthetic rubbers, fabric, steel-cords and other additives like carbon black and silica. Tire manufacturers are working continuously to replace non-renewable materials with renewable materials, as well as reducing the overall weight of the tire. Here are the main components of typical light truck and car tires:
1. Natural Rubber
Natural rubber is made from a white liquid called latex that oozes from certain plants when you cut them. There are over 200 plants in the world that produce latex. The most plentiful amount of latex can be found in the rubber tree. Latex is extracted from the rubber tree in much the same way that maple syrup is extracted. An incision is made in the bark of the Rubber Tree and latex is harvested slowly as it drips out of the live tree.
Rubber Trees can only grow in hot humid climates like in Brazil and South East Asia and require plenty of water. For that reason, it would be advantageous to be able to harvest latex closer to where tires are produced and at a lower cost. For example, Cooper Tire which has factories in the United States, and they are experimenting with Guayule as a source of latex. This is a plant that can flourish in the deserts of the Southwest United States, much closer to the manufacturing location than the rubber plantations of South America or SE Asia. Guayule requires very little water and produce good quantities of latex. Cooper Tire believes that Guayule is a viable source of latex to reduce the cost of making a tire and the overall impact on the environment. Other Manufacturers are looking for the same type of bio-based alternatives to latex from rubber trees.
2. Synthetic Rubber
A synthetic rubber is any artificial elastomer. The elastomers that go into tires are a petroleum byproduct. During the Second World War, the United States began mass producing synthetic rubber because natural rubber was in short supply to support the war effort. Today, there are nearly 20 types of synthetic rubbers, each produced through the petroleum refining process and containing unique ingredients that are added to make the tire last longer, grip better or to improve rolling resistance for better fuel economy. Per the US Rubber Manufacturer’s Association, about 70 per cent of all rubber used in tires is synthetic rubber.
3. Additives in Light Truck and Car Tires
Most tires are black. This is because a key ingredient that is added to the mix of natural and synthetic rubber is carbon black. Carbon black are tiny dust-like particles that act like a bonding agent for the other ingredients in the tire. Carbon black has the added feature of catching ultraviolet rays and absorbing the heat of the sun. This helps protect the tire against ozone and UV damage. No other additive has been found to be as effective as carbon black at protecting the rubber and prolonging the life of tires. In the absence of carbon black, ozone and UV rays would attack the molecules and chemical bonds of the rubber, which over time causes the rubber to rot, and weaken.
Another substance added to tires is silica. At a molecular level, silica is very rough and gritty. When mixed into tread rubber, it is this property that gives car tires extra grip on wet roads and on ice. Another property of silica is that it is very hard. This makes it effective at resisting wear due to abrasion and helps to extend the life of the tread. Silica is unique in that it improves the performance of the tire by making it last longer AND giving it better grip. Silica is relatively expensive, so it is not uncommon to find higher levels of silica in the more expensive light truck and car tires like Michelin tires, Bridgestone tires, Pirelli tires or Goodyear tires.
4. Steel Cords
An estimated 15% of the material in a tire is steel, mainly in the form of cord. Rubber is vulcanized to steel cords that are spirally wrapped to form bead wire. The bead is the part of the tire that attaches to the rim. It takes a lot of pressure to mount a tire on the wheel. You need a tight fit to ensure that air does not seep out. The rubber covered steel bead wire remains stiff and solid once mounted unto the rim. Besides the bead wire, Steel cord is often used to reinforce light truck tires in the sidewall area, and occasionally in the cap of the tire as added protection against punctures through the tread.
5. Nylon and Cotton Fabric
An important element in tires is the fabric belt that forms the casing of the tire and helps the tire maintain its shape even at high speeds. The casing forms the main body of the tire, and it is made of strips of cloth-like fabric that are covered with rubber. Each strip of rubberized fabric is used to form a layer called a ply in the body of light truck and passenger car tires. Passenger car tires may have as many as four plies in the body, so quite a lot of fabric is used in most pneumatic light truck and passenger car tires.
It is reassuring to know that tire companies are cutting down on using materials that are harmful to the environment, and cutting down on the amount of material used. A lighter-weight tire made of stronger materials will last the same amount of time while increasing fuel efficiency of the vehicle. As a result of less fuel used, CO2 emissions are also reduced. That is a good thing for the environment. Also, tires that last longer means fewer trips to replace tires. Tire manufacturers don’t have to produce as many tires, saving materials and the energy needed to create the tires. In the end, manufacturers producing high-quality, eco-friendly tires is in all our best interests.