A passenger tyre looks like a single black object. It is closer to twenty-five separate components, drawn from roughly two hundred raw materials, assembled cold and then fused into one body under heat and pressure. It begins in a Banbury internal mixer, patented by Fernley Banbury in 1916. Counter-rotating rotors fold polymer, carbon black, silica, oils and curatives together at 150 to 170 degrees Celsius, and the batch must be dumped before the accelerators wake up and cure the compound inside the machine. From there the components diverge: - Steel cord and textile fabric pass through a calender, which forces rubber into the gaps between filaments - Tread and sidewall are co-extruded, often as four compounds through a single quadruplex head - Bead wire, high-tensile steel near 2,000 MPa, is wound into hoops that clamp the tyre to the rim Assembly happens on a building drum and yields a green tyre: right shape, no tread pattern, no strength. Curing supplies both. A bladder inflates ...