Tire and Wheel
Cord Body: The cord body consists of layers of rubber-impregnated fabric
(or cords), called plies, that are bonded into a solid unit.
Bead: The bead is the portion of the tire that helps keep the tire in
contact with the rim of the wheel and provides the air seal on tubeless
tires. The bead is constructed of a heavy band of steel wire wrapped into
the inner circumference of the tire's ply structure.
Tread: The tread (or crown) is the portion of the tire that comes in
contact with the road surface. It is a pattern of grooves and ribs that
provides traction. The grooves are designed to drain off water, while the
ribs grip the road surface. Tread thickness varies with tire quality.
Sidewalls: These are the sides of the tire body. They are constructed
of thinner material than the tread to offer greater flexibility.
Wear Bars: Tires feature horizontal wear bars, bands or indicators in
the tread pattern that become visible when the tread has worn to a level
that is only 1/16 inch deep. After that level has been reached, they produce
a thumping sound to remind the drive that the tire is ready for replacement.