Ever more determinant in today’s motorsports, tires are fruit of constant research, high technology, thousands of kilometers worth of tests, and a myriad of materials… With the help of Le Cont, the Italian producer headed by brothers Valter and Sergio Cont, we unveil the “perfect” tire recipe.
The starting point of tire manufacturing are fabric cords: manufacturers choose textiles based on the desired features of the final product.
Before being bonded with the rubber compound that forms the actual tire tread, the fabric cords are pre-treated with a thin layer of adhesive rubber (only the big tire manufacturers do this operation in-house; smaller companies receive the fabric cord already finished) and are then cut into large diamond-shaped pieces.
This elements, together with bead wire loops and bead filler “wedges”, form the “carcass” or the basic structure of the tire.
Once the sides are reinforced with a thin layer of rubber to form the sidewall, the structure is then covered in tread, which (like the bead filler and the sidewall) is made of a rubber compound specifically formulated to yield the desired performance features.
The most common fabrics used in kart tire production are made of polyester , nylon, and (less often) rayon: the first generally for “slicks” and the others usually for “rain” tires.
Double or triple-ply, fabric cords differ by weave density.
Since the choice of fabrics influences the behavior of the final product, some of the major manufactuers have their textiles custom-engineered with specific characteristics.
Bead wire loops
The bead wire loop is also formed by several strings (generally 4 or 5) of steel wire woven together, covered by rubber, and wound into 5 inch loops (12.7 cm): the size corresponds to the diameter of the tire rim.
In shop-talk they are referred to as “wedges”: they are pieces of hard rubber compound (different compounds are used for front and rear tires) that are “extruded” to form cusps.
Their purpose is to …