Connection system between the two leading wheels which allows them to rotate with different angles so that they assume the same instantaneous rotation centre. The toe bar connected to the steering wheel is in front of the rigid axle which connects the two leading wheels.

The capacity of the tyre in filtering the road irregularities is evaluated in this item. This means its capacity of transmitting as little energy as possible to the car body and of producing the lowest level of noise on irregular road surfaces. Typical items are the softness, the roughness, the rhomboid shape, the impact of individual obstacles, etc.

Indicates the carcass components specifying the material and the effective number of plies.

It is basic element with which the resistant structure of the tyre carcass is made. It is made up of textile and metallic cords with resistant sections and variable thicknesses according to the characteristics of use.

The end of the ply of the carcass which is wrapped around the bead core and positioned against the carcass, in order to fix the ply and stop it from unthreading.

It is the quantity of energy that the motor must provide the wheels in the time unit to overcome the rolling resistance of the tyres. This energy should be subtracted from that made available by the motor. It depends on the speed, on the load and on the inflation pressure for a given tyre and for a given type of road. The power absorption is basically due to the internal molecular friction of the textile and the compounds (hysteresis) during the cyclical deformation of the tyre.

It is a circumferential rise positioned in the area of the side most exposed to accidental sliding.