Construction
Tires perform several important functions and are the only part of your vehicle that comes in contact with the road. The average “footprint” of a tire in contact with the road is similar to the bottom of an average man’s shoe sole. The entire weight of your vehicle and its contents is supported by the tire and air inside the tire.
Due to this critical role of tires, they are extremely complex in their design. While designs vary by product and manufacturer, an average tire contains over 100 separate components. Tires can include natural rubber, synthetic rubber, steel, nylon, silica (derived from sand), polyester, carbon black, petroleum, etc. The combination of ingredients and processes used by different manufacturers leads to different performance characteristics for every tire in the market today. Understand the basics of a tire and rely on your owner’s manual and professional tire retailer to explain the differences between tires and recommend the right tire for you.
Tire Functions
Tires perform four important functions with the assistance of the air contained within them:
1. Tires support the vehicle chassis off the ground.
2. They help absorb shocks from the road surface.
3. They help transmit acceleration and braking forces to the road surface.
4. Finally, they help change and maintain the direction of travel.
Technology
The technologies used in today’s tires are vastly improved over the tires of the early 1900’s. Improvements in raw materials and chemical compounds used in tires have led to tires that perform more effectively for their intended use. Whether we're talking about improvements in compound that offer better grip in snow and ice tires or compound enhancements that provide improved wet handling, technology continues to improve tire performance. Innovations in tread patterns, sidewall design and overall tire construction have also led to product improvements in today’s tires. Naturally, as types of vehicles and vehicle models continue to change, so too must tire construction and sizes.
Perhaps one of the most comprehensive technological innovations of the modern tire era is the invention of run-flat tire technology. While there are different types of runflat tires, the premise is the same: tires with run-flat technology allow consumers to travel a limited distance at limited speeds after a tire sustains complete air loss due to a puncture or cut. They are designed to allow a driver to travel to a safe location to change a flat tire.
Tire Construction
Although rubber is the main material used for making tires there are a number of other materials used as well.
These materials are combined with rubber compounds in the different components that make up the tire's construction.
Rubber Compounding
Rubber compounding is like mixing a cake recipe.
Different ingredients are mixed together to produce compounds with specific characteristics
Construction Components
Construction materials used by each tire manufacturer are chosen with their own technology in mind.
Each component of a tire is designed to provide benefits specifically related to its function, while working together with all other components
Tire Casing
The tire casing is the body of the tire.
Most passenger tire casings are one or two body plies.
The tire casing incorporates fabric of polyester, nylon or rayon cords within the casing rubber compound. These cords add strength to the casing rubber.
Polyester is the most common casing fabric used and provides: Good Rubber Adhesion, Excellent strength, Good Ride Characteristics
Polyester provides these features at a relatively low weight, while exhibiting heat dissipation characteristics.
Other fabric materials used in the tire casing include nylon and rayon, which exhibit slightly different benefits tuned to specific tire requirements.
Most passenger tires manufactured today are radials. Prior to radial construction, bias and bias belted construction was used.
The Belt System
The belt system is placed on top of the casing in the construction process.
The belt system's main function is to provide stability to the tread area of the tire, which contributes to wear, handling and traction.
The most common belt material used is steel. Steel belts provide strength and stability to the tread area without adding a lot of weight to the tire.
Usually two plies of steel cord placed at opposite bias angles make up the belt system.
The most common belt configuration is two plies of steel cord stacked, one on top of the other.
The Tread
The tread slab is placed on top of the belt system in the manufacturing process.
The tread usually contains two rubber compounds:
tread base compound adheres to the belt system when the tire is cured, is cooler
running improving durability and helps stabilize the undertread area of the tire.
The treadcap is typically made with an abrasion resistant, higher grip rubber compound, which works with the tread base and tread design to provide traction and mileage.
The tire's tread design is molded into the treadcap rubber during the curing process.
The Sidewall
A special rubber compound is used in the sidewall of the tire, which adds flexibility and weathering resistance.
Some tires, such as higher end performance tires, may also incorporate steel and/or nylon inserts to provide quicker steering response.
The Innerliner
A rubber compound is used as an air seal inside the tire. This innerliner layer has no cord reinforcing and serves a similar function as an innertube.
The Bead
Tire bead bundles secure the tire to the wheel. They are large monofilament steel cords that are wound together to form a cable or ribbon-type configuration.
The casing plies are looped around the bead bundles holding them in place.
Bead filler, a rubber compound, is incorporated within the bead configuration and extends up into the sidewall area.
The rubber compound used on the outside bead area is usually a hard, durable compound that withstands the rigors of mounting and chafing.
Passenger Tire vs. Light Truck Tire Construction
Differences between passenger and light truck construction are due to the different uses and operating conditions of light trucks versus automobiles.
Light trucks are usually designed to operate in more severe conditions, such as carrying greater loads more of the time and going off-road.
Light truck tires may have an extra casing ply, an extra belt, a stronger belt steelcord and/or a larger bead with more sidewall rubber. This is why light truck tires tend to be heavier than passenger tires.
Commercial light truck tires are also capable of higher air pressures and load carrying capacities. |
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| Tiremax has worked with Michael Garfield, The High Tech Texan, to put together a tire safety video to show you the highlights of keep you safe while on the road. Click on the button below to see the Tiremax Tire Safety Video. |
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