Tire Construction

Radial tires are the most common type of tire available today. Since the first radial tire in 1946, consumers have demanded radial tires for their superior handling, ride, tread wear, and fuel efficiency.

Tire Inner Liner
The inner liner of a tire is the first layer on the inside of the tire. It is designed to help prevent air loss.
Tire Bead and Bead Chaffers
The beads of the tire form the contact point between tire and wheel. They are made of high tensile strength steel wires and are surrounded by a hardened rubber compound. The beads ensure an airtight seal between the tire and wheel. The bead chaffers rest between the bead and the body ply of the tires. They prevent the bead wires from damaging the tire casing and improve the tire’s handling by making the sidewall above more responsive.
Tire Sidewall
A tire’s sidewall has many different and important functions. The sidewall of the tire provides protection for the inner layers from abrasions and cuts. By changing the sidewall construction, tire manufacturers are able to vary the handling characteristics and load carrying capabilities of the tire. For example, a stiffer sidewall may lead to more predictable handling but compromise the ride quality. The sidewall is also the location of important tire information such as size, load and speed rating and maximum air pressure.
Tire Casing
The internal structure called the casing is made up of the radial play, the steel belt package, and the cap ply.
Tire Radial Ply
The radial ply is one of the most important layers of the tire casing. It consists of rubber-bonded cords that run across the circumference of the tire at 90 degrees from the direction of tire travel. The radial construction helps absorb bumps on the driving surface and allows the tread and the sidewall to operate independently. This reduces flex in the tread, friction, and transverse slip, which leads to increased fuel efficiency, more responsive handling, and longer tread life.
Tire Belt Package
The tire’s belt package performs multiple functions including protecting the tire casing from road damage and creating the flat area for the tire tread. The belt package is made up of woven strands of high strength steel fibers, which are bonded to the rubber. The belt package enhances tire rigidity while remaining flexible enough to absorb bumps in the road.
Tire Cap Ply
Cap plies are used in performance tires and higher quality all season tires. The cap ply fights centrifugal forces and contains the belt package by maintaining the tire shape at high speeds, which leads to better braking and handling.
Tire Tread Area
The tread area is made up of many different features that work together to provide traction, handling, and ride characteristics. These features will vary depending on the intended use of the tire. Circumferential grooves are channels that run the full length of the tire. They help reduce hydroplaning by evacuating water away from the tread surface. They also help reduce tire noise by allowing air to pass under the tire. Lateral grooves are channels that run 90 degrees from the direction of travel. They enhance traction by removing water, snow, and mud from the tread design. Sipes are thin slits in the tread block that open and close as the tire rolls. This adds extra biting edges for enhanced grip in wet and icy conditions.

A solid or semi-solid rib is a tread bock feature that runs unbroken around the circumference of the tire. It enhances handling performance and dry weather traction. Large individual tread blocks increase traction in dry weather by placing more rubber in contact with the driving surface. The shoulder features of a tire may vary quite a bit. Some tires will utilize a solid shoulder to reduce road noise and improve cornering response. Others may have grooves used to channel away water, snow, and mud. Some may feature aggressive protrusions that add grip in off-road driving situations. One of the key features for a tire’s traction is the rubber compound.
Tire Tread Compound
While the tread has many different features, one of most important components is the tread compound. The tread compound varies from tire to tire based on the tire’s intended use. For example, winter tires are made with a compound that is designed to remain flexible when the temperature drops below 45 degrees. This helps to ensure traction, even in harsh winter conditions. At the other end of the spectrum, the rubber compound in summer performance tires is designed to perform at very high temperatures and very high speeds. It loses functionality in colder temperatures.

The all-season tire attempts to meet a broader set of consumer needs. The compound for an all-season tire is generally designed to supply dependable traction in dry, wet, and light snow conditions. The all-season compound is also designed to deliver more wear resistance. Due to the often-conflicting nature of tire performance demands, the tread compound is one of the most difficult and complex tire features to design.

Refer to the diagrams below for a better understanding of the elements that make up a tire.

Tire Tread

Tread Area (contact patch): The part of the tire that comes into contact with the road. The tread type is distinguished by the design of its ribs and grooves.

Shoulder: The part of a tire where the sidewall and tread meet. Certain tire designs feature shoulder blocks for better traction

Grooves: The space between two adjacent tread ribs; also called tread grooves.

Sipes: Cuts in tread blocks for water evacuation and biting edges on road surfaces.

Tread blocks: Form the tread pattern for wear resistance, stability, and traction.

Tire rib: Part of a tire tread pattern created by grooves that run circumferentially around the tire.

Belt Package

Cap plies: Maintain tread contour shape at high speeds to reduce heat build-up and impart rigidity to tread for enhanced grip.

Crown plies: Provide centrifugal and lateral rigidity to the tire, while also allowing the tire to flex sufficiently for a comfortable ride.

Edge plies: Reinforces shoulder shape of the tire for enhanced handling and grip.

Steel belts: Reinforces the tread region, providing flexibility and ride comfort.

Radial plies: Tire construction where the cords in the body run at 90 degrees to the centerline of the tread.

Radial cords: Run along the sidewall to allow for spring-like flexibility as a way to supply ride comfort.

Tire Bead

Bead Chipper: Protects the lower sidewall

Bead Flipper: Helps hold the bead in place

Bead: The beads are responsible for clamping the tire firmly against the rim of the wheel

Bead Chafers: Protects the wire bead components