The chafer of a bias tyre protects the bead and body from chafing (wear from rubbing) where the tyre is in contact with the rim.


The cord body is also known as the tyre carcass. It consists of layers of nylon plies. The cord body confines the pressure, which supports the tyre load and absorbs shocks encountered during driving. Each cord in each ply is completely surrounded by resilient rubber. These cords run diagonally to the direction of motion and transmit the forces from the tread down to the bead.

Aspect Ratio:

 - Section Height / Section width.

Rim Width:

 - Linear distance between the flanges of the rim.

Static Loaded Radius:

Distance from wheel axle centerline to supporting tread surface at a given load and pressure in a static condition.

Tyre Width (Overall Width):

The width of a new tyre, including 24-hour inflation growth, and including protective side ribs, bars and decorations.

Section Height:

Half the difference between the overall diameter and the nominal rim diameter.

Overall Diameter:

- The diameter of an inflated tyre at the outermost surface of the tread, including 24-hours inflation growth.

Tread Width:

 - Distance across tread from shoulder to shoulder.

Section Width:

 - Linear distance between outside of sidewalls of inflated tyre.

Width Loaded:

 - Tyre width (overall) under rated load conditions

The chafer of a radial tyre acts as a reinforcement. It increases the overall stiffness of the bead area, which in turn restricts deflection and deformation and increases the durability of the bead area. It also assists the bead in transforming the torque forces from the rim to the radial ply.