Bowden cable
The housing is generally of composite construction, consisting of an inner lining, a longitudinally incompressible layer such as a helical winding or a sheath of steel wire, and a protective outer covering.
It consisted of a stirrup, pulled up by the cable from a handlebar mounted lever, with rubber pads acting against the rear wheel rim.
The Bowden offered extra braking power still, and was novel enough to appeal to riders who scorned the plunger arrangement, which was heavy and potentially damaging to the (expensive) pneumatic tyre.
The problem for Bowden was his failure to develop effective distribution networks and the brake was often incorrectly, or inappropriately fitted, resulting in a good number of complaints being aired in the press.
Its most effective application was on those machines fitted with Westwood pattern steel rims which offered flat contact surfaces for the brake pads.
The potential of the Bowden cable and associated brake was not to be fully realised until the freewheel sprocket became a standard feature of bicycles, over the period 1899-1901, and increasing numbers of applications were found for it, such as gear change mechanisms.
The Raleigh company were soon offering the Bowden Brake as an accessory, and were quick to incorporate the cable into handlebar mounted Sturmey-Archer (in which they had a major interest) gear changes.
Early Bowden cable, from the 1890s and first years of the twentieth century, is characterised by the outer tube being wound from round wire and being uncovered.
An unpublished typescript exists in the archives of the National Motor Museum, written by the son of one of Bowden's employees that attempts to claim the invention of the cable for his father to the point of suggesting that it was never applied to bicycles before 1902.
British National Archives[6] In this narrative a flexible cable brake for cycles was separately 'invented' by George Frederick Larkin, a skilled automobile and motorcycle engineer, who patented his design in 1902.
The following year E.M. Bowden's Patents Syndicate Ltd. was formed to market the device but initially the project was a failure because all the company could offer was a flimsy mechanism capable of transmitting comparatively enormous power.
"[6]The original, standard Bowden cable housing consists of a close-wound helix of round or square steel wire.
A consequence of a long winding pitch in a support helix is that it approaches the case of parallel strands where the wires are bound only by the plastic jacket.
[7] A third type of housing consists of short hollow rigid aluminum or carbon fiber cylinders slid over a flexible liner.
[citation needed] Some applications such as lawn mower throttles, automobile manual chokes, and some bicycle shifting systems require significant pushing ability and so use a cable with a solid inner wire.
The other end is often clamped (as can be seen in the rear derailleur picture) to the part of the brake or shifter that needs to be moved, or as is most common with motorcycle control cables, fitted with another nipple.
In bicycle applications, for both brakes and gear-shifting, the outer dimension of the cap or ferrule that terminates a housing, is selected to make a loose fit within the barrel-adjuster's end.
If the inner wire is solid, as in automotive and lawnmower throttle and choke applications, it may simply have a bend at one or both ends to engage what ever it pushes or pulls.
Small rubber tori, called donuts, can be threaded onto a bare run of the inner cable to prevent it from striking the bicycle frame causing rattles or abrasion.
However, some care is needed in changing cables, since, for example, the 4 mm barrel adjuster end of an existing shifter is probably made only for that housing size.
The shortening of housings requires the use of a special hand tool, designed to make a square cut without closing the cable entry.
Modern lined and stainless steel cables are less prone to these problems; unlined housings should be lubricated with a light machine oil.
The specific resistance to compression or bending is never quoted, so there is much rhetorical evidence and comment as to the performance and durability of products, but little available science for the consumer's use.
[citation needed] A particularly severe quality test for housings is at or near the hinge of a folding bicycle where a sharp bend is made repeatedly.
