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
Outside tread compound provides traction and
Rubber located inside the tire adheres to the
belt system and helps provide stability to the tread area.
Rubber compounds may also differ due to the type
of other materials used in the tire.
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.
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 belt system
must also work in unison with the tire's sidewall and tread to
achieve traction and cornering capabilities.
are assembled like a puzzle and molded together in the curing
causes all of the tire components and rubber compounds to adhere to
their surrounding components, resulting in a singular product.
The tire casing is the body of the tire.
Most passenger tire casings are one or two body
The tire casing incorporates fabric of polyester,
nylon or rayon cords within the casing rubber compound. These cords
add strength to the casing rubber.
Weight is an important factor in virtually all tire
components. The heavier a tire is, the higher the potential for
building up heat during operating conditions. An excess build up of
heat in a tire eventually causes the rubber compounds to break down.
Polyester is the most common casing fabric used and
provides: Good Rubber Adhesion, Excellent strength, Good Ride
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 benefits similar to
Most passenger tires manufactured today are radials.
Prior to radial construction, bias and bias belted construction was
The belt system is placed on top of the casing in the
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 a bias
angle make up the belt system.
The most common belt configuration is two plies of
steel cord stacked, one on top of the other.
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
rubber compound is used as an air seal inside the tire. This inner liner
layer has no cord reinforcing and serves a similar function as an inner
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 car tires 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 steel cord and/or a larger bead with
more sidewall rubber. This is why light truck tires tend to be
heavier than passenger tires.
Some light truck tires are also capable of higher air
pressures and load carrying capacities