Motorcycle braking systems

, Gaydon, England Early motorcycles which were essentially a bicycle with a motor attached and did not have any braking system beyond cutting the power and waiting for the motorcycle to slow down enough to put a foot out. One of the first motorcycles to have any sort of braking mechanism was made by Steffey Motorcycles of Philadelphia in 1902. Drum brakes were first used on motorcycles in the 1920s and the basic design has not changed much. Originally used for braking both the front and rear wheels, drum brakes have largely been superseded by disc brakes or are used for rear-braking only. ==Drum brakes==

Drum brakes have a self servo effect. The most common design is a leading-trailing design. More exotic design had four, eight or sixteen shoes. Some motorcycles used finned and/or vented housings for additional cooling, the first of which was AJS. ==Disc brakes==

Discs Floating discs have better disc centering with a fixed caliper. A floating disc also avoids disc warping and reduces heat transfer to the wheel hub. Lambretta were the first manufacturer to use floating discs on a volume production motorcycle. Wavy discs place the mass closer to the axle for reduced inertia, Dual action, or opposed calipers, are fixed into position to reduce flex. Dual action have opposed pistons either side of the disc to greatly improve the piston area. Multi piston calipers Larger rotors can be used to increase braking force, but this also increases weight and inertia. To overcome this brake manufacturers developed calipers four, six and even eight pistons. Increasing the number of pistons increases the swept piston area, allowing for longer, narrower brake pads and smaller discs. Caliper mounting Early disc brake calipers were in front of the fork leg on top of the disc. This placed the caliper in an area of high air flow for better heat removal. Calipers on most modern motorcycles are mounted to the rear of the fork leg. This reduces the angular momentum of the fork assembly and improves low speed handling. Radial mounted calipers A radial brake caliper is mounted parallel to the forward direction on the braking system, making them more rigid than the traditional axial mount, and not prone to torsional flexing. Radial calipers can make modifying an existing disc brake with larger rotors simpler because the entire mounting bracket does not need to be replaced, needing only a spacer between the bracket and the caliper. Monobloc calipers machined from a single piece of metal are stronger, but much more expensive to make so some manufacturers such as Sumitomo cast the caliper body as one piece and then machine the piston bores externally with the holes created plugged after assembly. This type of caliper design has been used extensively by Yamaha on a wide range of models from its flagship Yamaha YZF-R1 to the more budget Yamaha FZS600 Fazer. Monobloc Brembo first used on the Ducati 1098. Perimeter brakes Buell Motorcycle Company adopted a rim-mounted disc brake that was said to reduce unsprung weight in the wheel-brake system, allowing lighter wheel spokes. Combined brake systems Anti-lock braking system ==Alternative new systems==

Drag-racing motorcycles can reach speeds up to over the course of the race and can use disc brakes in conjunction with parachutes to slow them after the timed run. The Streamliner class of motorcycle land speed record machines are mandated to have parachutes fitted if the motorcycle is capable of exceeding . Electric motorcycles can use regenerative braking to both slow the motorcycle down and recharge the batteries at the same. KTM secretly raced a machine with a KERS style regenerative braking system during the 2008 Valenican 125 cc Grand Prix. Although deemed in contravention of the rules, the use of a KERS system preceded its use in Formula 1. ==References==