Powersports / Motorcycles / Sport / CBR1000RR / Technology
The Steering Damper Comes of Age
Steering dampers are not new to the motorcycling scene. For decades, riders have resorted to using steering dampers, most often for extreme-use high-speed racing conditions in off-road competition as well as road racing. Regardless of the application, steering dampers help reduce excessive steering movement by incorporating a damper connecting a motorcycle's fork and frame. Some units use simple friction dampers, while others are of hydro-mechanical design.
In general, Honda® avoided installing these devices on motorcycles because all existing designs included inherent drawbacks that compromised the benefits. Typically, when a steering damper was set for high-speed performance, the motorcycle's handling would be adversely affected at moderate and lower speeds--not a good trade-off for general-purpose riding. If a compromise setting was selected to mollify a steering damper's negative effects on low-speed handling, the high-speed benefits were similarly reduced--again, not much net gain. So when Honda's engineers decided a maximum-performance machine such as the CBR®1000RR would benefit from the positive aspects of a steering damper, they simply decided to reinvent the device to reap the full rewards while eliminating the historic drawbacks.
Unlike past designs, the new Honda Electronic Steering Damper (HESD) has no fixed damping characteristics. Instead, damping action is controlled by the CBR1000RR's Electronic Control Unit (ECU), which automatically varies damping force according to vehicle speed and acceleration over a wide range of riding conditions. Jointly developed in cooperation with Kayaba, the HESD mounts atop the steering head and a linkage arm connects the HESD to the triple clamp. Within the damper unit, a large chamber filled with oil is divided into two sections by a moving vane connected to the linkage arm. In response to steering movements transmitted by the linkage arm, the vane forces oil between the left and right sides of the chamber through various passages, including a main valve controlled by a linear solenoid that receives its control signals from the ECU.
At lower speeds, the damper's main valve opens fully and therefore creates virtually no perceptible damping effect. Result: a light steering feel. As speed and rate of acceleration increase, the linear solenoid constricts oil flow between the two sides of the chamber, resulting in the desired amount of increased steering damping. Four one-way check valves ensure that oil flows through the main valve in only one direction, whether the vane is moved to the right or the left. A relief valve maintains internal pressure below a designated set level, while another small piston compensates for temperature-induced changes in oil volume.
Technical aspects notwithstanding, CBR1000RR pilots will reap the benefits of the new HESD in the form of confidence-inspiring handling, making the riding experience all the more enjoyable. Once again, Honda has harnessed technical sophistication into a seamless package that enhances the pleasure of riding.