autofreak
12-24-2008, 05:43 AM
DUOLEVER
BMW is the only manufacturer to successfully implement an alternative. Its Telelever system, as fitted to boxers like the R1200GS and R1200RT, has been around long enough to be no longer lumped with the 'funny front end' tag. It separates the loads by having hollow forks that only have to deal with directional duties, while a wishbone hanging from the engine's crankcases attaches to the forks on a pivot just above the front wheel and passes suspension forces to a monoshock hanging from a front subframe beneath the tank. This wishbone also passes braking loads away from the steering and suspension, straight to the engine/frame. This set-up has the added advantage of looking like conventional forks to the 'more casual observer. But the Duolever system on the K1200S is a little more a.dventurous. A solid, cast aluminium leg holds the front wheel, sticking up towards the bars just as forks would. It's attached to the frame by two trailing links that hang from the front like mini swingarms and pivot on rose-joints on the cast leg.
141
The bottom link acts on a shock, the top of which is located on the underside of the headstock, the trapezoidal assembly compressing under suspension loads. A hinged link from the handlebars on top of the headstock transfers steeringto the leg holding the wheel. Assuming you're still with us, this design has more pronounced advantages than the Telelever system. Steering and suspension loads are more effectively separated, because they bypass the headstock completely. The leg holding the wheel doesn't have to slide, so it can be the optimum system is 10% lighter than the Telelever system. There is natural anti-dive under braking, though the links can be tailored to allow a small degree of dive for better feel and weight transfer, and a rising rate shock action is easy to engineer in, if required.
BMW is the only manufacturer to successfully implement an alternative. Its Telelever system, as fitted to boxers like the R1200GS and R1200RT, has been around long enough to be no longer lumped with the 'funny front end' tag. It separates the loads by having hollow forks that only have to deal with directional duties, while a wishbone hanging from the engine's crankcases attaches to the forks on a pivot just above the front wheel and passes suspension forces to a monoshock hanging from a front subframe beneath the tank. This wishbone also passes braking loads away from the steering and suspension, straight to the engine/frame. This set-up has the added advantage of looking like conventional forks to the 'more casual observer. But the Duolever system on the K1200S is a little more a.dventurous. A solid, cast aluminium leg holds the front wheel, sticking up towards the bars just as forks would. It's attached to the frame by two trailing links that hang from the front like mini swingarms and pivot on rose-joints on the cast leg.
141
The bottom link acts on a shock, the top of which is located on the underside of the headstock, the trapezoidal assembly compressing under suspension loads. A hinged link from the handlebars on top of the headstock transfers steeringto the leg holding the wheel. Assuming you're still with us, this design has more pronounced advantages than the Telelever system. Steering and suspension loads are more effectively separated, because they bypass the headstock completely. The leg holding the wheel doesn't have to slide, so it can be the optimum system is 10% lighter than the Telelever system. There is natural anti-dive under braking, though the links can be tailored to allow a small degree of dive for better feel and weight transfer, and a rising rate shock action is easy to engineer in, if required.