Tires are a primary vehicular component that we cannot do without, seldom think about unless they fail and can cover thousands of miles without failure. A truly marvelous example of modern manufacturing. The tire is a mixture of over two hundred ingredients that fall into five groups:
• Natural rubber is the primary component of the tread layers
• Synthetic rubber part of the treads of car, van and truck tires.
• Carbon black and silica is used as a reinforcing agent to improve durability.
• Metallic and textile reinforcement cables that form the skeleton of the tire, forming up the geometric shape and providing rigidity.
• Chemical agents are added to give the tire many of its properties like low rolling resistance or ultra-high grip.
Tire Tread Design Guide
Tires are designed according to usage. They may be all black and round but a sports car tire is considerably different than those all-terrains on your 4 x 4 three-quarter ton land cruising truck. Certain design features aid in the tire’s utility.
• The number of grooves or groove ratio. The more the grooves and larger the better the tire pumps out water and increases traction in wet conditions.
• The shape and layout. Ever study the tire tread design? The shape of the tread pattern, whether it is symmetrical, asymmetrical or direction all affect the rate and efficiency of the water shedding ability of the tire.
• Sipes, those thin slits in the rubber surface of the tread, improve traction in wet conditions, and work with ice as well. They act like the wipers on the windshield, the sipes aid the edges and grooves of the tire to drain away water.
• The tires profile or shape: If flat with square shoulders provides good support in turns in dry conditions.
• For dry conditions narrower and fewer grooves allow more rubber to be in contact with the road providing a higher level of grip.
• Bigger tread blocks the better the traction, the downside is more noise.
• Self-locking sipes: tread blocks with many sipes helps to reduce the rigidity of the tread pattern. To counter this the sipes are designed in three dimensions which tend to lock together under load.
Not only are tires a potpourri of chemicals but a lot of design work as well, but remember tires are designed to match the general conditions and environment they will be used in.
Parts of a Tire Assembly
The design that nearly all tires have in common, going from the outside in:
• Tread, the part we see with all the grooves and stuff. It is designed to resist wear, abrasion and heat.
• Belts or crown plies provide rigidity for the tread.
• Cap play or zero-degree belt. This layer reduces friction heating. The tire is somewhat flat on the bottom but round everywhere else meaning the tire does a lot of flexing and thus builds heat in the tire. In fact, there is a tire rating for heat. This layer helps to maintain the shape of the tire at higher speeds. To prevent centrifugal stretching of the tire, this layer is reinforced with nylon-based cords embedded in a layer of rubber and placed at the circumference of the tire.
• Casing ply: This area determines the strength of the tire. It has fine, resistant cords bound in rubber. This is to provide strength against the strains of maneuver, as in turning and resists expansion due to tire rotation. It must be flexible enough to absorb deformations caused by bumps, ruts and potholes. This is the heart of the tire.
• Side walls support the tread and provides protection against side impacts, you know, tire and curb contact. All the tires specs are written on the sidewall.
• Beads are the wire reinforced area the seals the tire against the wheel with an airtight fit. Each bead wire can take a load of nearly 4,000 pounds without risk of breaking. There are two per tire and eight per 4 wheels. That’s a total of almost 32,000 pounds of resistance strength. The average passenger weighs about 3,300 pounds, down from behemoths of the sixties and seventies.
• The lower bead area is where the tire rubber grips the metal rim. The vehicles engine power and breaking forces are transferred through the wheels through the bead to the tire’s contact area with the road.
• Carcass ply is the layer above the inner liner is built up of thin textile cords or cables bonded into the rubber. The cables are what determines the primary strength of the tire and helps it to resist pressure. Standard tires contain about 1,400 cords allowing the near standard inflation pressure of about 33 pounds per square inch.
• Inner liner, the modern replacement for the inner tube and provides an air-tight layer of synthetic rubber.
Roadside Assistance & Fluid Delivery in Irving, Fort Worth, Arlington, Carrollton & Plano Texas
As marvelous a construction that a tire is, they due fail and as part of our service, Speedway Towing & Roadside Assistance offers tire changes if you should get a flat tire or blowout. Call us for all your towing and roadside assistance needs.
