To ensure optimum sporting ride and handling the XKR's springs
and dampers are uprated compared to the XK. The front spring rate
is increased by 38% and the rear spring rate by 24%. Allied to the
Servotronic steering system, which has been tuned both mechanically
and electronically to give the steering more weight and even
greater response, the uprated suspension ensures
confidence-inspiring handling without any loss in refinement and
comfort levels.
Because of the inherent strength and stiffness of the chassis,
and the addition of a rear suspension brace engineered to
accommodate the significant increase in rear spring rate, the XKR
Coupe and Convertible have the same dynamic settings.
The Computer Active Technology Suspension (a two-stage adaptive
damping system that ensures the optimum balance between ride and
handling) and new switchable Dynamic Stability Control with
Traction Control System (Trac DSC) have also been recalibrated to
complement the additional power of the supercharged engine.
As significant to the XKR as the increases in power and torque
are the major improvements in body stiffness, strength and weight
compared to its predecessor. Unique in the industry for being a
volume production complete aluminium monocoque body structure, as
distinct from an aluminium spaceframe with separate aluminium
exterior panels, its properties come from both the way the
bodyshell is designed and constructed and the use of new joining
technologies.
The new XKR's aluminium chassis is significantly lighter and
stiffer in both Coupe and Convertible form than the steel model it
replaces. The Coupe chassis is more than 30 percent stiffer than
the previous XK, while the Convertible is over 40 percent stiffer.
As a consequence the XKR accelerates faster than the previous
model, while offering high levels of safety, reduced noise and
vibration intrusion, and improved ride and handling characteristics
thanks to improved suspension dynamics. In Convertible form the BIW
weight, at just 287kg is 19 percent lighter than the previous
XKR.
New, larger ventilated brake discs at the front ensure even
better braking performance for the XKR. The front brake disc
diameter has increased from 326mm to 355mm and the thickness from
30mm to 32mm, which not only improves braking but also the system's
resistance to fade. The braking system also includes four-channel
ABS, Electronic Brake Force Distribution, Hydraulic Brake Assist to
increase brake pressure during an emergency stop, and Jaguar's
Electronic Park Brake function.