The rims of wire wheels (or "wire spoked wheels") are connected to their hubs by wire spokes. Although these wires are generally stiffer than a typical wire rope, they function mechanically the same as tensioned flexible wires, keeping the rim true while supporting applied loads.
Wire wheels are used on most bicycles and still used on many motorcycles. They were invented by aeronautical engineer George Cayley and first used in bicycles by James Starley. A process of assembling wire wheels is described as wheelbuilding.
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Before 1960, sports/racing cars often had wire wheels equipped with "knockoff" (central wing nut) hubs that could be unscrewed by striking a wing of the nut with a mallet or "knockoff hammer", but in the 1960s cast light-alloy or "Magnesium" wheels became common and now predominate. New versions of wire wheels are made with standard hub bolt patterns covered by a center cap to fit without adapters.
The first commercially successful use of wired wheels was on bicycles. They were introduced early on in the development of the bicycle, following soon after the adoption of solid rubber tires. This development marked a major improvement in bicycles, over the older wooden wheels, both in terms of weight and comfort (the increased elasticity of the wheel helping to absorb road vibrations).[1]
In England, the engineer William Stanley developed the steel-wired spider wheel in 1849, an improvement over the cumbersome wooden spoked wheels then fitted to the tricycles that his employer was making.[2][3][4]
Bicycle manufacturers build millions of wheels annually, using the common crossed-spoke patterns whose crossings of adjacent spokes are governed by the number of spokes in the wheel. Wheelbuilders of racing teams and in good bicycle shops build wheels to other patterns such as two-cross, one-cross, or no-cross (usually called radial). Many of these patterns have been used for more than 100 years, it is claimed that crossed patterns have more strength and stability while irregular patterns are art forms and have little structural merit (Brandt, 1993).
In the 1980s, cast wheels with 5 or 6 rigid spokes began to appear in the Olympic Games and professional racing: these have advantages in specialized applications, such as time trials, but wire-spoked wheels are used for most purposes.
The reaction to a radial load of a well-tensioned wire spoked wheel, such as by a rider sitting on a bicycle, is that the wheel flattens slightly near the ground contact area. The rest of the wheel remains approximately circular.[5][6][7][8] The tension of all the spokes do not increase significantly. Instead, only the spokes directly under the hub decrease their tension.[9][10][11][12] The issue of how best to describe this situation is debated.[13] Some authors conclude from this that the hub "stands" on those spokes immediately below it that experience a reduction in tension.[7][9] Other authors conclude that the hub "hangs" from those spokes above it that have higher tension than the ones below it.[11]