TREAD DESIGN

The tread is the part of the tire that contacts the pavement. The correct choice of tread design for a specific application can mean the difference between a satisfied and a dissatisfied customer.

A PROPER TREAD DESIGN

• Improves traction
• Improves handling

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 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."

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 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.

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.

TIRE 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 tire. 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 tires enhance straight-line acceleration by reducing rolling resistance. They also provide shorter stopping distance. Unidirectional tires must be dedicated to a specific side of the vehicle. Care must be taken when rotating unidirectional tires to ensure that the repositioned tire rotates in the correct direction.

SYMMETRICAL TREAD PATTERN

Consistent across the tire's face. Both halves of the tread face are the same design.

TREAD DESIGN AND WET ROAD CONDITIONS

There are both block and rib tread patterns used in street-tire 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 tire. 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 tire's contact with the road.