Avon Safety Wheel

{{Unreferenced, date=December 2009 The Avon Safety Wheel was a new type of

wheel A wheel is a circular component that is intended to rotate on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machines. Wheels, in conjunction wi ...

for

car A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded as ...

s, invented by the Avon Tyre Company of

Britain Britain most often refers to: * The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands * Great Britain, the largest island in the United King ...

in the early 1970s. With the advent of

radial tyre A radial tire (more properly, a radial-ply tire) is a particular design of vehicular tire. In this design, the cord plies are arranged at 90 degrees to the direction of travel, or radially (from the center of the tire). Radial tire construction ...

s, taking over from the older crossply type, it was found that in the event of a puncture or blowout, the tyre would be much more prone to detach from the rim, which would make a bad situation somewhat worse. The Avon Safety Wheel avoids the detachment of a deflated tyre by having a much shallower central recess within the interior of the wheel. The recess is so shallow that the tyre is prevented from twisting to an angle that would allow it to slip over the edge of the rim, so it is retained. Such a shallow recess would also prevent the fitment of new tyres, if it weren't for the inclusion of a deep channel, allowing the bead of the tyre to enter the channel to permit fitting. The channel is covered by a metal band that is tightened around the wheel after the tyre is fitted but before it is inflated. The fitting procedure is relatively troublesome and not popular with tyre fitters. This may be one reason that this design of wheel has not been widely adopted, meaning that modern cars are still prone to tyre detachment, though tyre safety itself has improved dramatically in the last 30 years. The Avon Safety Wheel was first used on the 1974

Vauxhall Firenza The Firenza is a model of car offered by Vauxhall from May 1971 until 1975. It was a development of the Viva, but had a distinctive coupé body style (fastback) and only two doors. In South Africa, it was sold as the Chevrolet Firenza until it ...

. The wheel design was also used on

British Leyland British Leyland was an automotive engineering and manufacturing conglomerate formed in the United Kingdom in 1968 as British Leyland Motor Corporation Ltd (BLMC), following the merger of Leyland Motors and British Motor Holdings. It was partl ...

Morris Marina The Morris Marina is a front-engined, rear-wheel-drive C-segment, small family car that was manufactured by the Morris Motors, Austin-Morris division of British Leyland from 1971 until 1980. It served to replace the Morris Minor in the Mo ...

Safety Research Vehicle, though featuring very different styling from the version employed by Vauxhall. It was also used on the Bristol 411 series 4. Tires