Jaguar XK Chassis

Jaguar\'s Lightweight Aluminium Chassis

The light, ultra-stiff all-aluminium monocoque body of the all-new XK forms a solid basis for the suspension components. The reduced body weight also allows other components to be located as required to deliver optimum weight distribution and avoid any compromises with optimum suspension layout. The XK uses Jaguar’s well proven and classically sporty combination of unequal length wishbones at the front and unequal length wishbones using the driveshafts as upper links at the rear. The body’s light weight and careful packaging provide the perfect platform for Jaguar’s renowned expertise in combining exceptional handling and roadholding with comfort and refinement.

In unison with this ultra-stiff body Jaguar is able to use a conventional, mechanically sprung suspension layout, with coil springs and telescopic dampers all round, that gives more natural, more positive feedback to the driver, exactly as a sports car should.

The stiff and lightweight body has allowed us to engineer precision and agility into the new XK without losing refinement. It may sound obvious, but it’s much easier to tune the dynamics on a car that is intrinsically right in the first place. And while the basics are all there, this is also a very advanced car. The driver is the centre of attention and we’ve used technology to help us where it makes sense.

Mike Cross, Jaguar’s chief engineer

That technology includes a new version of Jaguar’s Computer Active Technology Suspension (CATS), which is a two-stage adaptive damping system that ensures the optimum balance between ride and handling whatever the road conditions or style of driving. The car’s pitch and yaw rates are measured using accelerometer sensors. That data, plus information on steering wheel angle and brake demand, is processed by the control module, and electronically controlled hydraulic valves continuously vary the damper settings accordingly. In the previous XK, the CATS system adjusted front and rear dampers in pairs, limiting the control variation to pitch only. The all-new XK’s version controls all four dampers separately, which allows control of roll as well as pitch, for even better ride and handling balance, with a very sporty feel.

Wheels and Tyres

The all-new XK offers a choice of aluminium alloy wheel designs in two sizes, with the standard Tire Pressure Monitoring System (TPMS) and the option of a run-flat tire specification.

The 4.2-litre XK has 18-inch alloy wheels as standard, with the option of 19-inch wheels. Both the 18 and 19-inch wheels have conventional solid rims. On each model, and whatever the wheel diameter, the rear wheels are wider than the front ones – to optimize the steering characteristics, handling balance and traction.

With 19-inch wheels, run-flat tires will be available as optional equipment. They are designed to allow the driver to drive on following a puncture, and are capable of travelling for 50 miles (81 km) at speeds of up to 50mph (81 km/h) after a total deflation. The new XK offers Jaguar’s new Tire Pressure Monitoring System (TPMS), which uses a pressure sensor in each wheel continuously to monitor each tire.

Data from the sensor is transmitted by radio frequency to a receiver in each wheel arch, and in turn to the central control module. In the event of a loss of pressure, the system displays clear warnings in the instrument cluster to help the driver to take appropriate action. The TPMS system is standard equipment. Where run-flat tires are fitted, no spare wheel needs to be carried in the luggage compartment and the unused spare wheel well is fully trimmed and shaped to take a suitcase and increases the total loadspace by 1.06 cu. ft. (30 litres).

Brakes

The all-new XK features a braking system with bigger ventilated discs, more stopping power, better pedal feel and better resistance to fade than the previous XK.

Extensively tested at facilities including Nardo in Italy and the Nürburgring test track in Germany, where Jaguar has a permanent research facility, the new brakes are also specifically tuned to be more responsive for the enthusiastic driver. The new XK has four-channel ABS with analogue control which is more refined than simpler ‘on-off’ digital controls, and Electronic Brakeforce Distribution which ensures the correct balance of braking forces between all four wheels irrespective of road or vehicle-load conditions. It also uses Jaguar’s excellent Electronic Parking Brake system.