The new Bentley Continental Flying Spur makes its international debut at the Geneva Salon on March 1 and will begin its global roll-out from April 2005. Sharing heart and soul with its highly successful stablemate, the Continental GT, the Continental Flying Spur is a four-door Grand Tourer born of a coupe.

Bentley Continental Flying Spur - Chassis and Engineering

Bentley occupies a unique position in the marketplace. Whereas other manufacturers offer either hard-edged sports saloons or rear-passenger orientated limousines, Bentley effortlessly straddles the gap between these two extremes, building grand touring masterpieces that offer refinement and performance in equal measure. The Continental Flying Spur is no different, as member of the board, engineering, Dr Ulrich Eichhorn explains:

"All Bentleys must be able to pamper and perform when called upon. In the Continental Flying Spur you can be cruising along enjoying the highest comfort and luxury with superb ride quality. Then all you need to do is press the accelerator and the car is transformed. That is the character of the Continental GT coupe and one of our engineering challenges was to keep the family characteristics that people admire so much."

To ensure that the entire Bentley Continental range shared those qualities it was essential that both models had the right building blocks. The basis of the cars is an exceptionally stiff steel chassis and by extending the wheelbase of the Continental Flying Spur by 300mm (12 inches) the design team ensured the car had the spacious rear legroom that was a key objective.

The body of the new Continental Flying Spur is immensely stiff (46Hz resonance frequency) and this provides an extremely stable platform for the suspension and steering components for optimum on-road performance.

An increase in wheelbase helps the refinement and ride quality of any car, but that didn't stop the engineers carrying out a complete chassis retune. The Continental Flying Spur shares the same basic suspension system as its coupe equivalent - a four-link arrangement at the front and a trapezoidal multi-link rear axle with computer-controlled air springs and fully variable, electronically controlled shock absorbers in place of conventional coils. To optimise refinement and ride quality for the longer four-door model, however, significant changes have been introduced:

• Redesigned electronic dampers within the air spring units ensure a suitable blend of sportiness and refinement.
• New suspension bushes and reconfigured software are also introduced to complement the revised dampers.
• A new aluminium subframe at the rear provides a light, stiff and strong platform for the multi-link rear suspension.
• New aluminium uprights at the front lower the unsprung weight of the car and consequently improve all-round steering feel and rolling comfort.

One of the immense benefits of computer-controlled suspension is the ability to maintain a static ride height regardless of the load the car is carrying, as Keith Sharp, manager, chassis, suspension and vehicle dynamics, explains:

"By adjusting the suspension to control the car's height we can constantly ensure the optimum level of ride refinement. The other major advantage is that we can use the air suspension to change the attitude of the car at higher speeds to improve stability. We have programmed the Continental Flying Spur's suspension to lower the nose by 10mm and the rear end by 25mm at speeds over 155mph (250km/h). This reduces rear end lift at high velocities and means our car feels very stable, rather than nervous, as your speed increases."

Thanks to a continuous all-wheel drive system, the Continental Flying Spur is blessed with astonishing traction and poise whatever the weather. In standard conditions the drive is transferred equally between the front and rear axles via a highly sensitive centre Torsen differential. If, however, the differential detects a deviation in torque demand between the two axles it automatically sends more power to the wheels indicating greater grip.

As well as its advanced all-wheel drive system, the Continental Flying Spur incorporates traction control and an Electronic Stability Programme (ESP), both of which can be disabled at the discretion of the driver. These driver aids operate discreetly, offering additional security and governance over the car's dynamic potential but without being intrusive, thereby ensuring the unique Bentley driving experience remains undisturbed.

The advanced technologies used in the Continental Flying Spur's suspension were rigorously tested on proving grounds, test tracks and roads across the world. The result is a car whose breadth and capability, in any weather, on any road surface, is simply awesome. Over the course of its development the car was subjected to a drive programme that saw it complete nearly a million miles.

"When it came to prototype driving and development we utilised the finest facilities all around the world," says Dr Ulrich Eichhorn, member of the board, engineering. "The car was extensively tested at internationally recognised venues such as the Nurburgring, Nardo and the Grossglockner mountain pass. We also adopted some new development processes that married tried and tested practices with Bentley specifics. The result is a car that has been developed to the highest possible standards."

Evidence of this thorough testing process is seen in the Continental Flying Spur's revised steering. To ensure that the car handles in a way that is suitable for a luxury saloon as well as a high-performance grand tourer, a new steering rack was engineered. To improve driver feel friction was reduced in the steering column, rack and suspension ball joints. The system's responsiveness was also adapted to suit a four-door grand tourer, with a slightly lighter weighting around the centre for more relaxed driving at high speeds and a more linear increase in loading as it begins to corner. The new rack also means the Continental Flying Spur has a highly competitive 11.8-metre turning circle kerb-to-kerb - an impressive figure for a car with such generous accommodation.

Wheel and tyre choice is a vital part of the handling and dynamic characteristics of the Continental Flying Spur. The car will come with single-piece 19-inch alloy wheels as standard and will run on bespoke 275/40 R19 tyres produced by Pirelli and Michelin.

A final visual aid to help create that unmistakeable sporting presence is an optional 20-inch two-piece alloy sports wheel. This seven-spoke rim has a combination of chrome and silk finishes and retains the distinctive 'Bentley Motors' hub. The new two-piece sports wheel also wears a brand new tyre created exclusively for the larger rim and recently introduced as part of the Continental GT's optional Mulliner Driving Specification. Designed on behalf of Bentley by Yokohama, the Advan Sport 275/35 R20 tyre provides significant benefits for drivers looking for even sportier handling and improved steering feel and response.

The culmination of an intensive development programme carried out by both Bentley and Yokohama engineers, the new tyre has a lower sidewall that provides sharper turn-in feel and precision. The Yokohama Advan Sport manages to deliver increased performance without noticeable reduction in overall ride quality, meaning drivers will continue to enjoy the unparalleled luxury of the Continental Flying Spur and now benefit from its increased sporting characteristics.

Braking is provided by huge ventilated disc brakes - the largest of any production passenger car on sale today. The front discs are 405mm in diameter and 36mm wide, and the rear discs 335mm in diameter and 22mm wide. These are retarded by aluminium single-sided callipers branded with cast aluminium 'Bentley' logos.

The braking system features a Bosch anti-lock system with Brake Assist and electronic pressure distribution. The Continental Flying Spur also has a unique electronic parking brake - after the driver has applied the brake it will automatically re-apply one and five minutes later. This prevents accidental slippage should the brake discs cool after use. The parking brake system can also be operated as an emergency brake. In this instance braking is applied to all four wheels and the car's electronic safety systems remain fully operational allowing the driver to steer as normal.

The Continental Flying Spur also offers enhanced occupant safety with the use of a tyre-pressure monitoring system that constantly measures the tyre pressures in all four wheels and instantly warns the driver should a significant reduction occur.