Car tires were initially off white, due
to the natural color of the rubber used. Pure vulcanized rubber is
soft and wears out very quickly and tends to heat up and deform
under load. Tire makers mixed zinc oxide in with the rubber that
added temperature stability and hardness, and which made the tires
bright white in color.
As the benefits of adding carbon black to the compound became
known, that additive was used just on the tread portion, while the
side of the tire remained the natural color, the original
whitewall tires. Adding carbon black made the tires darker, and
they lasted four to five times longer.
Binney & Smith began selling their carbon black chemicals to
Goodrich Tire Company (now Michelin). Binney & Smith would
later switch to making school products, and, eventually, re-name
their company after their most popular product, Crayola Crayons.
There are a few tire manufacturers that make specialty color
tires, mostly for car shows, and during 1961, Goodyear Tires
introduced an experimental tire that was illuminated from the
inside. Small incandescent bulbs were mounted inside the tire
through holes inside the rim and the tire was made from a single
piece of synthetic rubber. The synthetic rubber was created much
thinner than a regular tire to allow for the light to penetrate
the rubber. Due to the strict laws regarding the manufacturing of
street-legal tires and the obvious hazard of having fragile glass
inside them, Goodyear’s illuminated tires never actually saw mass
production.