Maximum driving precision and directional accuracy
Duolever front suspension by BMW Motorrad combines the greatest possible ride comfort and sensitive feedback with outstanding directional stability. BMW Motorrad engineers based its development on a patented design by the British inventor Norman Hossak. Back in the 1980s he was responsible for the dual semi-trailing arm front suspension on some BMW models.
In terms of kinematics the Duolever front suspension comprises a four-bar linkage in which two semi-trailing arms made of forged steel are secured to the frame by means of roller bearings. These guide the extremely torsion-resistant fork slider which is made from aluminum gravity die casting and visually resembles a conventional fork. A central suspension strut, which is linked onto the lower of the two semi-trailing arms and is supported against the frame, performs suspension and damping.
A trapezoid-shaped scissor-type articulation, which is borne at the steering head and fork slider, is coupled with the handlebars. This transmits the steering motion. Unlike telescopic forks, the Duolever construction gets by entirely without any sliders and fixed fork tubes as a result. At the same time it separates the two functions of steering and damping from one another even more than the tried-and-tested Telelever. This separation effect of the steering and suspension functions results in maximum comfort and road grip for riders, enabling them to enter entirely new territory in this respect.
The benefit of this front suspension, which is currently the most innovative on the motorcycle market, is its evident torsion-resistance. Whereas sliders and fixed fork tubes on a conventional telescopic fork twist both sideways and lengthways during compression/rebound of springs and steering, the Duolever front suspension by BMW Motorrad has no such negative effects. Its two semi-trailing arms absorb the forces that arise during compression and rebound, keeping the fork slider stable. Any torsion is thereby prevented and the front suspension is very precise. The rider's steering commands are accordingly implemented immediately and feedback from the front wheel is entirely clear in all road situations.
The targeted arrangement of the longitudinal steering bearing also attains kinematic anti-dive control like with the Telelever before it. Whereas a conventional telescopic fork is highly compressed during sudden braking maneuvers or even becomes solid, with the Duolever, sufficient residual spring travel is even retained in these situations so that the rider can brake very late and nevertheless maintain a stable direction on bends.
It has also been possible to implement the evasion direction of the front wheel when riding over uneven surfaces on the Duolever so it is similar to the behavior of a telescopic fork. Combined with the lower unsprung masses and the system's low breakaway forces, this results in extremely sensitive and comfortable response characteristics.
Duolever front suspension by BMW Motorrad combines features that until now were incompatible, namely directional stability at high speed, agile handling, a precise steering sensation and directionally stable braking efficiency in all speed ranges.
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