Manufacturing a Safe Passenger Tire
Tires are not usually the subject matter in most topics of conversations, but we all trust our lives to tires every day. So let’s look at how tires are made. They can be large such as heavy truck or industrial tires, they can be small such as tri-cycle wheels, but most tires manufactured today are for your passenger car. Today’s tires are well made based on a standard manufacturing process and are made to take a beating on the roads, by-ways, or hi-ways and never miss a “beat”.
Tires are the only part of your car that is in contact with the road. Also, the weight of your vehicle is supported by a cushion of air inside each of your tires. Today’s tires are made of many materials, natural and synthetic rubbers, including steel and light weight fabrics. Each part of your tires has a uniquely important job. Besides the critical role that tires play in supporting the weight of your vehicle, the tire components and tread design are complex and have a direct impact on your safety. (3)
Most passenger cars have radial tires which consist of one or two plies that are constructed of rubber, light weight fabric and steel cables. Tread plies are added for stability and resistance to puncture. Each ply is actually made of up of individual cables laid side by side, and enclosed in rubber to form a uniform tire.
Blending the inner parts of your tires is where the manufacturing process begins. A tire’s rubber blend can have many separate ingredients used for different recipes, each affecting the performance of a tire’s characteristics. Different rubbers, textile fabrics, beads, steel belts, ply, and tread are mixed together during blending to create a very hot black compound that is then ready to be “milled”. Once the rubber compound cools, it is cut into strips at a “tire mill”. The strips will form the structure of the tire.
Many tire parts are also constructed during the milling process, some of which are coated with different types of rubber. (2) The ingredients are added and blended at high temperatures, which can rise as high as 320 – 338 degrees Fahrenheit. The blending temperature must reach 212-230 degrees Fahrenheit for each batch. The blending process is usually completed in two stages. “Curing” the tire is normally accomplished in the final stage of blending.
At this point in the manufacturing process a “green tire” is cured in a vulcanizing™ machine, which uses hot molds to compress all the tire’s parts together. The tire is given its final shape during the curing stage and is stamped with a tread pattern and a sidewall identification marking. (2)
Before a tire can be considered ready for distribution and sale, it must be carefully inspected. Each tire is visually inspected by trained professionals using machines designed to pick up any blemish or imperfection. A sample of tires are pulled from the production line to x-ray, searching for potential internal weaknesses or failures. Quality control engineers also randomly select tires off the line and cut them open to carefully look at every detail of the tire’s construction to ensure they meet “industry” standards. (1)
The inspection process involves visual checks by trained experts as well as mechanical tests that will identify even the slightest fault or potential weakness. A tire is pulled from the sample and placed on a test wheel, inflated, and rotated at a particular velocity. Once the tire passes inspection on the test wheel, it can be moved to a warehouse for distribution and eventual installation on your car.
The manufacturing process is all about consistency to make high quality tires the consumer can rely on at an affordable price. Spare tires are as much a matter of marketing as security and safety. Meaning, SUVs and light trucks tend to retain their fifth standard tire. Most passenger cars these days get by with a temporary emergency only mini spares.
Tires are manufactured for every make and model passenger car and are dependable, rugged, and made with your safety in mind. Each tire is manufactured to an industry standard, maintained by professionals as well. Your car tires are made to be a very important part of your vehicle’s passenger safety.