YOKOHAMA Tyre Construction Flowchart
You may not be familiar with some terminology describing processes used in tyre manufacturing. Below are definitions of the terms unique to the tyre industry.

Internal Mixer
The internal mixer is a large multi-story enclosed mixer used to mix oil, rubber and chemicals into all the rubber compounds used in manufacturing tyres.

Bead Wrap
This the process that forms the bead. After the bead wire is coated with rubber it is wrapped forming the circle-shaped bead that will be used in constructing the bead assembly.

Bead Wire
See Bead Assembly.

Calendaring
Calendering is a process in tyre manufacturing where steel or fabric is coated with rubber. Steel belts, body plies, cap plies and belt edge covers are all produced using the calendering process. Steel or fabric is placed between two large heavy rollers. Rubber is also inserted between the rollers at the top and bottom of the material being coated. As the material moved through the rollers the pressure forces the rubber to permeate and adhere to the steel or fabric.

Curing
Is the process where a green tyre is the assembeled components that make up a tyre before it is cured. Curing bonds all the different rubber components of a tyre together. The tread design and sidewall nomenclature are also molded into the tyre during the curing process.

Extrusion
Extrusion is a process used to manufacture shaped solid rubber. Treads, sidewalls and bead fillers are manufactured using extruders. An example of extruding is cake decorating. To decorate the cake the decorator squeezes icing through tips shaped to form different shapes. The decorator is extruding icing.

Tread Components
Tread Design
The tread is the part of the tyre that contacts the pavement. The correct choice of tread design for a specific application can mean the difference between a satisfied or dissatisfied customer.

A proper tread design:

• Improves Traction
• Improves Handling
• Increases Durability

Tread design also affects other customer concerns such as:

• Ride Comfort
• Noise Level
• Fuel Efficiency

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.

Blocks
Those segments making up a tyre'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."

Dimples
Indentations in the tread that improve cooling.

Shoulder
Provides continuous contact with the road while maneuvering. Shoulders wrap slightly over the inner and outer sidewall of a tyre.

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 tyre has a high or low void ratio depends on the tyre's intended use.

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 tyre. 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.

Tyre Life
There are many factors to consider when researching and developing a tread design-steering response, cornering power, traction, stability, noise and treadwear are but a few. The aesthetics of the tread design are also a big factor. Many customers base much of their purchase decision on tread appearance.

Asymmetrical Tread Pattern
The tread pattern changes across the face of the tyre. Usually incorporates larger tread blocks on the outer portion for increased stability during cornering. The smaller inner blocks aid in dissipating water.

Unidirectional tread pattern
Designed to rotate in only one direction, unidirectional tyres enhance straight-line acceleration by reducing rolling resistance. The also provide shorter stopping distance. Unidirectional tyres must be dedicated to a specific side of the vehicle. Care must be taken when rotating unidirectional tyres to ensure that the repositioned tyre rotates in the correct direction.

Symmetrical tread pattern
Consistent across the tyre's face. Both halves of the treadface are the same design.

Tread Design and Wet Road Conditions
Both block and rib tread patterns are used in street-tyre design. Grooves are used to create voids within the tread face for better water channeling on wet road surfaces. The most efficient means of channeling water is circumferentially around the tyre. It is the shortest distance between the front and rear edge of the contact patch. However, lateral grooves help break up the wedge of water that forms at higher speeds. This reduces the chance of hydroplaning and increases the tyre's contact with the road.