It is the angle between the centreline of the tyre and the vehicle directrix (observing the vehicle from above). Toe is conventionally positive (toe in) when the distance between the front edges of the wheel is less than across the trailing edges and negative when it is vice versa; in this case it is called toe out.

It is the angle between the centreline of the tyre and the vehicle directrix (observing the vehicle from above). Toe is conventionally positive (toe in) when the distance between the front edges of the wheel is less than across the trailing edges and negative when it is vice versa; in this case it is called toe out.

Toe in is the angle between the centreline of the tyre and the vehicle directrix (observing the vehicle from above). Toe is conventionally positive (toe in) when the distance between the front edges of the wheel is less than across the trailing edges and negative when it is vice versa; in this case it is called toe out.

Toe out of the front wheels expressed in degrees and conventionally measured with the wheel turned 20°.

It is the surface generated by rotating the section profile of an inflated tyre around a rotation axle.

It is caused by two equal weights placed asymmetrically to the tyres centreline and not uniform along the circumference. When the tyre begins rotating, the two unbalanced weights generate two centrifuge-like forces. These forces in turn cause a torque which will cause the tyre to wobble. This wobbling will have a negative effect on driving comfort and on the wear of the mechanical elements of the vehicle and of the tyres.

It is the capacity of the tyre to maintain a good friction coefficient with the road surface in all conditions of use of the vehicle (braking, acceleration, bends).

This means the replacement of the original equipment of a vehicle with tyres of other sizes usually belonging to the wide series in which the rolling circumference of the lower cover must be the same as that of the base cover. In order to perform a correct transformation, appropriate technical criteria and legal provisions must be followed.

A band of rubber alone which surrounds the carcass, in the area where it comes into contact with the ground. It consists of a rubber compound and a pattern capable of guaranteeing both good abrasion resistance and good adherence to the ground both in dry and wet conditions, as well as low noise characteristics when driving. The tread pattern consists of a particular arrangement of blocks and grooves (grooves, sipes, etc.). The main materials are natural, synthetic rubber, carbon black, vulcanising agents and aging protection.

Individual element of the tread pattern. The block may be quadrangular, trapezoid, rhomboid, circular, polygonal, etc. according to the tread pattern.

More or less open channels in the tread pattern whose main job is to help the water under the contact area to flow away.

Term used to indicate the noise emitted when the tyre rolls in contact with a mainly flat road surface at a reasonable speed. This type of noise is caused by the hammering of the tread pattern blocks on the carcass, by vibration and sliding of the blocks in the contact area, by the air trapped in the tread elements under the contact area escaping, etc... By changing the arrangement of the different length blocks (variable pitch), without modifying the basic nature of the individual pitches, their succession in time is changed and as a consequence the ear may have less accentuated and more tolerable sensations with the same overall sound energy.

The tyre design or "sculpture". It varies according to the tyre purpose (i.e. rain/wet are more grooves and channels for optimum water dispersion, whilst dry/tarmac tyres are less grooved as they function is to maximize the contact area with the ground).

Particular orderly arrangement of blocks and grooves and sipes of the tread pattern of differing length in order to improve the quality of the tread noise.

The tube type tyre consists of a tyre in which an inner tube, which contains pressurised air, is fitted. The valve for inserting, sealing, controlling and topping up the pressurised air is part of the tube.

It is the international term adopted to define tyres for fitting without an inner tube. The tubeless tyre consists of an internal wall lined with a thin layer of special impermeable rubber called a liner which ensures an airtight seal under pressure. This type of tyre must be fitted on a special rim to which the valve is directly fitted.

This abbreviation is located on the tyre near the wear indicators. They consist of 1.6mm high rubber projections located in the main grooves of the tread.

It consists of the Cover, the inner tube (where foreseen), Rim and pressurised air.

A "mix" or combination of raw materials used in the manufacture of the rubber compound of the tyre itself. By varying the percentage or the composition of the materials applied, manufacturers can produce different tyres for various purposes and with different performances.

Implies the method used to manufacture the tyre carcass. The two main methods are "Radial" (a tyre with plies arranged in a way that cords in the body run at 90 degree angles to the center line of the tread) and "X-Ply".

The exchange of tyres from one axle to the other without cossing-over. This operation must be carried out every 10,000-15,000 km in order to optimise wear and enable all four tyres to be replaced at the same time.