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A wishbone suspension refers to a type of suspension used in automobile manufacturing that is typically manufactured from steel or aluminum and resembles a large letter "Y" or "A" or the wishbone in a turkey or chicken. Also known as an A-frame, the wishbone suspension commonly attaches to the front or rear wheel and hub assembly with the single point and at the chassis with the two points. This wishbone suspension system prevents the wheel from turning to the side and maintains a straight tracking tire. By operating in a double wishbone suspension with one wishbone at the top and the second wishbone at the bottom of the wheel hub, the suspension is able to effectively travel through its full range of motion without coming out of alignment.
The A-frame or wishbone suspension is one of the most widely used suspension systems worldwide. Easily maintaining camber angles, the wishbone suspension has been used on nearly every type of vehicle from horse-drawn buggies to automobiles and trailers. The early wishbone suspension used on Ford's 1930s-era vehicles have been dubbed by hot rodders as the most beautiful suspension system ever used on a vehicle. It was, however, not uncommon for early hot rodders to cut the wishbones in half and create double-radius arms to adorn the front of their hot rods.
In a single straight-axle suspension system, the axle is mounted on leaf-type springs. Another not-so-common method of suspending a straight axle lies in the form of coil springs and the use of a panhard bar to maintain the axle's positioning. This suspension system has been used on every type of vehicle manufactured around the world and remains a popular choice for heavy equipment such as tractor trailer semi-trucks and heavy trucks. The advent of the double A-frame or wishbone suspension enabled manufacturers and designers to build the independent suspension.
By suspending the front wheel assemblies between an upper and lower A-frame, the wheel is allowed to articulate up and down while maintaining a straight up-and-down position. This design allows a wheel to maneuver over a bump or obstacle without altering the wheel's camber. Camber refers to the degree of angle or lean or tilt at which a wheel rides. Most vehicles operate with a few degrees of positive camber.
Negative camber refers to a tire that is tipped out just a little at the top of the tire. By operating a tire and wheel at positive camber settings, the outside wheel will roll straight up when taking a turn sharply. This gives the vehicle the utmost in traction and control.