Steering dampers are not new, but
the traditional damper has been superceded. For years,
riders have fitted steering dampers for high-speed racing
conditions in off-road competition as well as road racing.
Whatever the application, steering dampers help reduce excessive
steering movement by incorporating a damper connecting a motorcycle's
forks 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 CBR1000RR 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
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
Technical aspects notwithstanding,
CBR1000RR riders 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.