Tire Basics

A tire or tyre is a flexible container of compressed air. This air container support the vehicle's load; propels a vehicle forward, backward and side-to-side, stops the vehicle, and cushions the load from road imperfections.

Sipes
Small, slit-like grooves in tread blocks that allow the blocks to move more. This added flexibility increases traction by creating an additional biting edge. Sipes are especially helpful on ice, light snow and loose dirt.
Belt
The belt is a reinforcement layer extending around the outer circumference of the carcass under the tread. It acts like an iron hoop in improving the stiffness of the tread area. In the case of truck and bus tires, the belt is more heavily reinforced compared to passenger car tires.
Bead
The bead area supports the extremities of the carcass on each side of the tire. This is the part of the tire that anchors the tire to the wheel.
Blocks
Those segments making up a tire's tread. The primary function of tread blocks is to provide traction.
Ribs
The straight-lined row of blocks that create a circumferential contact "band."
Shoulder
Provides continuous contact with the road while maneuvering. Shoulders wrap slightly over the inner and outer sidewall of a tire.
Void Ratio
The amount of open space in the tread. A low void ratio means more rubber is in contact with the road. A high void ratio increases the ability to drain water. Whether a tire has a high or low void ratio depends on the tire's intended use.
Sidewall
The sidewall on each side of the tire, between the shoulder and the bead is the section that deflects most during running. The rubber coating serves to protect the carcass.

On the sidewall of every passenger-car and light-truck tire is an alphanumeric code that describes the dimensions of the tire. For most tires, this code will start with a "P". Some may start with an "LT" to signify light truck. Some tires may have a "Max. Load" indication . When selecting new tires, it is important to make sure a tire's load rating is at least a high as the tire you are replacing.
Dimples
Indentations in the tread that improve cooling.

Want to choose the best Yokohama tire for your needs?
It helps to first understand all the components of a Yokohama tire from the tread design to the construction elements.


Parts of a Tire
Grooving
Used to create voids for better water channeling on wet road surfaces. It is the most efficient means of channeling water from in front to behind the tire. By designing grooves circumferentially, water has less distance to be channeled. Circumferential grooves provide the shortest distance from the front to the rear edges of the contact patch.
Tread
The tread is the part of a tire that contacts the road surface. The tread consist of a layer of rubber, compounded to suit the application purpose of the tire, and the thickness serves to protect the belt and carcass. The tread pattern serves the purpose of improving water drainage, providing traction, braking and cornering characteristics and long tread life.
Carcass
The carcass is the load-bearing framework that forms the body of the tire. It is composed of rubber coated steel cords laid in a radial direction. In consideration of the importance of a tire's load-bearing capability, truck and bus tire carcasses are more heavily reinforced than those of passenger cars.
Bead Filler
This is a reinforcement rubber that has a triangular cross-section and which is used to increase the stiffness of the bead.
Bead Wire
A ring-shaped reinforcement material that is made by bundling together several steel wires.
Steel / Nylon Chafer
The chafer fabric and/more steel cords is wrapped around the bead section in order to reinforce it. It is conventionally composed of steel. However, the specification may sometimes call for the use of nylon.