Dunlop Tyres

Glossary of Tyre Terms

The checking and adjustment of caster, camber and toe angles in a vehicle's suspension to maintain specifications engineered by the vehicle manufacturer for optimum performance.

A bead using aramid fibres which are a class of heat resistant and strong synthetic fibres.

The relationship between the section height and section width of a tyre expressed as a percentage of section width. If the section height is one half the section width, the aspect ratio is 50%.

Tyres which have a tread pattern that is different from one side to another.An Assymetrical tyre offers the best of both excellent dry grip as well as enhanced wet performance.

The equal distribution of the mass of the tyre and wheel assembly for smooth driving. Balance is achieved by fitting weights to the wheel rim to offset uneven weight distribution of the tyre or wheel.

An inextensible hoop of high tensile steel wires which anchors the plies and conforms to the rim seat to hold the tyre onto the wheel rim.

The inner ledge portion of the wheel rim where the tyre bead rests adjacent to the flange.

The band of multiple tyre cords compressed of usually rubberized steel wires beneath the tread and laid at opposing angles that determine the tyre's diameter and stabilizes the tread by resisting deformation from cornering, braking and centrifugal forces. These do not tie into the tyre beads.

The angle between the centerline of the tyre and a vertical line as viewed from the front.

A cornering force generated by the tyre's camber.

The tyre body, composed of plies which form the tyre's structure and give it shape. Sometimes called the carcass.

The angle between the vehicle's steering axis and a vertical line, as viewed from the side.

A patented design process whereby the tread blocks are spaced unevenly in order to minimise tyre noise and reduce the intrusive frequencies often heard inside a vehicle.

The combining of five basic ingredients: rubber, carbon black, plasticizers, curing materials and ozone retardants to form the tread and other "rubber" components of a tyre.

The area of the tyre's tread that is in actual contact with the ground. (See Footprint.)

The lateral frictional force generated by a cornering tyre, acting in opposition to the centrifugal force.

The center area of a tyre's tread.

The difference between a tyre's unloaded or free radius and the loaded radius.

Tyres that have a tread pattern that is designed to operate best when rotating in one direction.The tyre pattern is usually chevron or arrow shaped with grooves running from the central portion of the tyre to the shoulders.

The tendency for a tyre to roll in its steered direction rather than follow road contours.

Dunlop Self-Supporting Technology. An advanced tyre design that permits limited driving after loss of inflation pressure. Requires a pressure monitoring system.

The area of the tyre's tread that is in actual contact with the ground. (See Contact Patch.)

A revolutionary design whereby the tread pattern on the inner shoulder of our Asymmetrical pattern allows for the deflection of water like a turbine achieving the highest level of aquaplaning safety in all speed ranges

The condition that exists when a tyre's mass is not evenly distributed around the rolling axis and centerline, causing bounce (static imbalance) or shake (dynamic imbalance).

The pressure of the air inside a tyre, which applies a tensile stress to the tyre cords, permitting them to carry the vehicle's load.

A continuous wrap of fabric wound over the steel breaker in the tread area of a tyre.This wrap effectively eliminates a joint and therefore enhances high speed stability and prevents the tyre from expanding at high speed which ensures an even and wide contact area at all speed levels

The thin layer of halobutyl rubber inside a tyre that contains the inflation air, sometimes called the inner-liner. All Dunlop passenger tyres are manufactured with an inner-liner.

Also found in our Asymmetric pattern this describes the two wide cental ribs all the way around the tyre which ensures the the efficient transmission of lateral forces.The result is excellent handling and a high degree of driving comfort at any speed

Fitting tyres of different sizes, ratings or constructions to a vehicle. Mixing should be avoided. Some performance vehicles, however, specify different size tyres on front and rear axles. See vehicle's Owner's Manual.

The act of fitting tyres to wheel rims.

Dunlops exclusive technology which ensures a uniform pressure distribution in the contact patch which quite literally results in more of the tyre being in contact with the road more of the time.

The diameter of an unloaded, inflated tyre measured from the crown on one side to the crown on the opposite side. The free radius equals one-half of the overall diameter. Sometimes called the outside diameter.

The condition that exists when a tyre is inflated beyond the pressure corresponding to the actual load or beyond the vehicle manufacturer's recommendation.

The situation that occurs in cornering when the rear of a vehicle tends to skid before the front and rotate in the original direction of travel.

This refers to the outer shoulder tread design on our Asymmetrical pattern where the arrangement of the shoulder blocks are spaced in such a way that will eliminate disturbing high frequencies which results in particularly low rolling noise and safe handling.

The reinforcing members of a tyre composed of layers of cord fabric and rubber that provide the strength to contain the air pressure needed to support a load and resist deflection.

A method whereby the tyre is designed using computer simulations to enhance stablity and to allow for even and superior tread wear

The tyre construction utilizing plies whose cords run radially from bead to bead under the tread. This construction requires a belt to stabilize the tread and define the tyre diameter.

The measured number of revolutions made by a tyre traveling one kilometer.

The portion of a wheel incorporating the well, seats and flange onto which a tyre is mounted.

The diameter of the rim bead seats that support a tyre are normally indicated in whole numbers in inches for passenger cars.

The systematic movement of tyres from one vehicle position to another to maximize tread life and minimize irregular wear.

The measure of the out-of-roundness of the tyre causing a vibration which cannot be balanced.

A tyre that is designed to resist the effect of deflation when punctured and to enable the vehicle to continue to be driven at reduced speeds(up to 90km/h) and for limited distances of up to (160km) without damaging the vehicles rim. (See DSST)

The distance between rim flanges.

A slice of a tyre from one bead, through the tread, to the other bead.

The vertical distance from the bead edge to center of the crown in an unloaded tyre.

The distance between a tyre's sidewalls measured at the widest part of the tyre. Each size of tyre is measured on a specific rim width.

A designation of a tyre's aspect ratio. A tyre with an aspect ratio of 60% is a 60 series tyre.

The edge of a tyre's tread where it joins the sidewall.

The portion of the tyre between the bead and the tread.

The angle between the direction in which a tyre is aimed or steered and the actual direction of tyre travel.

A letter designation identifying the tyre's high-speed durability

The difference between the front and rear edges of tyres mounted on an axle. Toe-in means the front edges are closer together than the rear edges and tyres point inward. Toe-out means the front edges are farther apart than the rear edges and the tyres point outward.

The design process used by Dunlop whereby the tyre is engineered based on the superior road feedback on prototype and test tyres as experienced by the driver ie:The enhanced two way communication flow between the driver and the road and the speed of transferring the drivers commands into car response.

The region of a tyre designed to contact the ground. It is molded of tough rubber for high traction and low wear.

The arrangement of blocks, grooves, sipes and channels designed into the tread to enhance its grip. Also called the tread design.

Areas in the tread, such as grooves and channels, that permit water to drain away from the footprint.

The measure of the life of a tyre tread, usually described in number of kilometers.

A tyre construction that uses a rubber inner-liner inside the casing to prevent air leakage and eliminate the need for an inner tube.

The condition that exists when there is not sufficient air pressure in a tyre to support a specific load. This causes the tyre to operate with excessive deflection, mechanical flexing and heat.

The condition that exists during cornering when the front of a vehicle tends to skid before the rear.

A tread design on the shoulders of the tyre incorporating uneven spacing between tread blocks which not only delivers superior traction but also reduces noise for a quieter ride.