Press Release
Chassis and Driver Assistance Systems: Dynamics, Comfort and Safety Tailored to the Driver.
The BMW 1 Series Coupé offers the driving pleasure so typical of the brand now also in the segment of compact four-door models, the elaborately engineered chassis underlining the dynamic and sporting character of this new BMW. The result is superior steering and driving precision even under extreme conditions reaching the very limits of driving physics.
With its design principle quite unique in this category – engine at the front, drive wheels at the rear – the new BMW 1 Series Coupé offers optimum traction, exemplary weight distribution with approximately 50 per cent of the car’s overall weight on the front and rear axles, respectively, outstanding directional stability and safe handling. And the separation of drive power, on the one hand, from the car’s steering, on the other, is of course the prerequisite for supreme agility on the road.
Elaborate design principle on the front and rear axles.
The rear axle on the BMW 1 Series Coupé is a sophisticated five-arm structure designed to meet the specific requirements and demands of the high-power and high-torque engines. The result is extremely precise wheel guidance, also because rear track is another 20 millimetres or 0.79" wider than on the three- and five-door versions of the BMW 1 Series.
An anti-roll bar serves furthermore to reduce body roll in fast bends, and the entire drive axle is designed from the start for superior agility and optimum noise insulation.
The final drive on the new BMW 1 Series Coupé has been optimised for smooth running qualities, double-helical ball bearings serving to reduce the operating temperature achieved more quickly thanks to the smaller oil capacity of the final drive housing.
Again, both of these modifications serve to enhance the car’s functions and running life, the final drive also helping to reduce fuel consumption to an even lower level.
The front axle of the BMW 1 Series Coupé likewise offers a standard of quality and elaborate design quite unique in the compact class: The double-joint spring strut tiebar axle is made largely of aluminium, the anti-roll bar is designed as a hollow tube combining superior stiffness with low weight – together with a high standard of stability on the track control arms and bars as well as exact wheel guidance for superior driving dynamics.
Runflat tyres and Tyre Defect Indicator featured as standard.
Both the chassis springs optimised for tension and weight and the twin-sleeve gas-pressure dampers are matched to the specific performance of the individual body versions. As the top model in the range, the new BMW 135i Coupé comes as standard with an M sports suspension lowering the entire body by 15 milli-metres or 0.60 – and also available as a factory-fitted option on the other model variants.
A further important point is that the BMW 135i Coupé is fitted as standard with high-performance brakes featuring brake callipers finished in grey and proudly bearing the name “BMW” in white.
Further signs of distinction on the 135i Coupé are 18-inch light-alloy wheels running on specially developed, traction-optimised tyres varying in size front and rear. The BMW 120d Coupé by contrast, comes as standard on 16-inch light-alloy wheels, the BMW 123d Coupé on 17-inch light-alloy wheels.
All model variants of the new BMW 1 Series Coupé feature runflat tyres as standard equipment, allowing the driver to go on even under complete loss of tyre pressure at a maximum speed of 80 km/h for a distance of at least 150 kilometres or 90 miles.
Yet a further standard feature is the Tyre Defect Indicator permanently monitoring air pressure in all wheels and warning the driver through a signal in the instrument cluster once tyre pressure drops more than 30 per cent below the ideal level.
Electromechanical power steering for enhanced precision and greater fuel economy.
With the exception of the top-of-the-range model, all variants of the new BMW 1 Series Coupé come as standard with energy-saving EPS Electric Power Steering complete with an integrated Servotronic function for speed-related steering assistance.
EPS ensures even greater precision and steering comfort, at the same time reducing fuel consumption since, unlike a conventional mechanical-hydraulic system, steering assistance is provided by an electric motor operating only on demand, that is only when really required.
As an option the new BMW 1 Series Coupé is also available with Active Steering adjusting the steering transmission ratio to the respective road speed of the car. This means that when parking or manoeuvring, the driver requires only minimum effort to move the steering wheel in the right direction. Then, with road speed increasing, the steering becomes less direct, giving the driver a more superior steering feel at higher speeds.
To transmit movements of the steering wheel, Active Steering comes with an additional transmission unit on the steering line, the steering angle or lock determined by the driver being modified by means of an electric motor via a planetary gearing. The degree of modification chosen in this process is based on the current speed of the car and its lateral acceleration taken into account by yaw rate control.
Networked with Dynamic Stability Control, Active Steering, when intervening, generates a discreet counter-steering effect in fast bends which the driver will not even feel but which serves to additionally stabilise the car. Via yaw rate control, Active Steering will also stabilise the car when applying the brakes on different surfaces (modal split application of the brakes). The specific counter-steering effect generated in this way helps to prevent the vehicle from serving out of control.
Dynamic Stability Control with additional functions.
All versions of the BMW 1 Series Coupé come as standard with ABS anti-lock brakes and ASC Automatic Stability Control preventing the drive wheels from spinning above all when setting off.
CBC Cornering Brake Control also fitted as standard stabilises the car whenever necessary when applying the brakes in a bend.
These functions are all integrated within DSC Dynamic Stability Control preventing the car from swerving round at the rear (oversteer) or "pushing" out of a bend over the front wheels (understeer) in a particularly challenging situation by applying the brakes specifically as required on individual wheels and reducing engine output accordingly. Even then the car retains its dynamic driving character.
Interacting with optional Active Steering, DSC is furthermore able to prevent the car from swerving out of control when applying the brakes on surfaces with different frictional coefficients (for example when aquaplaning or with slippery ice on only one side of the car, that is with a so-called modal split) by counter-steering as required.
In the new BMW 135i Coupé DSC Dynamic Stability Control offers an even wider range of functions including the Start-Off Assistant preventing the vehicle from rolling back when setting off on an uphill gradient and automatic Fading Compensation to prevent the typical fading effect whenever the brakes are extremely hot.
Pre-loading of the brakes whenever a need for particular stopping power is indicated by the driver suddenly letting go of the accelerator pedal ensures an enhanced brake standby function. Dry Braking, finally, improves the effect of the brakes in the wet by applying the brake pads slightly at regular intervals in order to remove a film of water from the brake discs.
DSC Dynamic Stability Control in the new BMW 1 Series Coupé also comes with an integrated wear indicator for the brake pads. Applying the data provided in this way, the electronic “brain”, conducting the Condition Based Service (CBS) function as part of BMW Teleservices, calculates the remaining distance until the driver is required to change the brake pads.
DTC Dynamic Traction Control is a special sub-function of DSC, allowing greater slip on the drive wheels and thus optimising the car’s traction and pulling forces under particularly difficult road conditions. As a result, the new BMW 1 Series Coupé is able to set off smoothly in, say, deep snow with the wheels intentionally allowed to spin slightly – an advantage in such a situation.
Last but not least, DTC also allows even more intense lateral acceleration up to a controlled drift in bends. And if he wishes, the driver is able to deactivate the DSC system completely.
Electronically controlled differential lock function for even better traction in the BMW 135i Coupé and the BMW 123d Coupé.
To ensure optimum traction at all times, given the high power and muscular torque of the engine, the new BMW 135i Coupé and the new BMW 123d both come with special improvements serving to enhance traction and pulling force whenever required. The main consideration in this process is to support the driver in a sporting and ambitious style of motoring, for example when accelerating out of bends and hairpins.
Should the driver of one of these models deactivate DSC Dynamic Stability Control and DTC Dynamic Traction Control completely, an electronically controlled differential lock function in the DSC-off mode still ensures optimum traction, with appropriate brake force being applied on the inner drive wheel possibly spinning in a tight bend. This enhances the car’s traction and pulling force on the road without any negative effect on its steering behaviour.
Body and Safety: Strength and Protection of the Highest Standard.
A wide range of features serving to optimise the car’s passive safety confirms the premium character of the BMW 1 Series Coupé. Indeed, all the safety standards and requirements made of BMW’s larger model series have been carried over in full to the unique body structure of the new model, the highly dynamic BMW 1 Series Coupé thus offering also an optimum standard of motoring safety quite unique in its performance range.
Once again, the BMW Group’s engineers, in creating this car, prove their mastery in combining low vehicle weight for optimum fuel economy with an extra-stable body structure ensuring maximum safety on the road. As a result, the new Coupé offers all the qualities required for excellent results in all consumer safety tests relevant the world over.
The extremely stiff passenger cell, interacting with carefully laid-out deformation zones front and rear, is particularly effective in keeping out forces acting on the car from outside. Six airbags as well as crash-optimised seats are further standard features of this compact car.
Stable bodyshell for superior protection in all directions.
One of the objectives in developing the body of the new BMW 1 Series Coupé was to achieve optimum safety on minimum weight, ranking the car right at the top versus international competition also in this respect. High-load-resistant, extra-large carrier structures in the floorpan, in the side frame, on the bulkhead, in the roof area, and on the rear partition to the passenger compartment provide the foundation for the high level of passive safety in the BMW 1 Series Coupé.
In addition, the use of high-strength steel and reinforced panels on the body surfaces, as well as intelligently coordinated deformation zones at the front and rear, serve to effectively protect the driver and passengers from external forces.
The load paths serving in the event of a head-on collision with complete or restricted overlap to divert undesired forces away from the passenger cell were all calculated by computer simulation with optimum precision and carefully checked in advance. Particularly the interaction of front body deformation and passenger cell stiffness ensures a high standard of all-round efficiency on the bodyshell.
Proceeding from computer-generated data, the BMW 1 Series Coupé further-more benefits from a concept serving to keep forces in a collision from the side beneath essential biomechanical limits. Part of this concept is formed by the crash-resistant doors, while the crash-optimised front seats, the reinforced B-pillars and the instrument panel between the A-pillars all interact in the interest of enhanced side stability supplementing the very stiff passenger cell.
Despite this robustness, the car looks particularly sporting and light from outside, above all the low greenhouse moved far to the rear setting off the more muscular elements of the very safe bodyshell through its looks and appearance.
Special floorpan guiding impact forces to the opposite side in the event of a collision.
The special structure of the floorpan serves in particular to enhance crash safety to an even higher standard: The floor assembly incorporates a carrier structure conveying impact forces to the opposite side of the car in a collision in order to protect the occupants.
The passenger cell with its extremely strong pillars and crossbars developed especially for the Coupé, as well as the extra-strong roof frame structure, serve to maintain the occupants’ survival space also in a rollover.
Highly efficient restraint systems.
No less than six airbags come as standard to round off the wide range of features for optimum passenger safety in the new BMW 1 Series Coupé.
Depending on the severity of an impact, the frontal airbags are activated in two stages, particularly the front passenger’s merging smoothly into the instrument panel: Unlike conventional airbags often still found in the market, the airbag panel joints are covered in this case by PVC film and thus remain invisible to the eye.
The side airbags integrated in the front-seat backrests reduce the risk of injury at chest and hip level in the event of a collision from the side, while the curtain head airbags housed in the roof lining protect both the front-seat occupants and the passengers sitting at the rear.
Padded headrests and backrests on the crash-optimised seats significantly reduce the risk of occupant injury in the event of an impact from behind.
All seats come with three-point inertia-reel seat belts and headrests. The belt pivot fasteners are mounted directly on the frames of the driver’s and front passenger’s seats, ensuring optimum belt geometry at all times regardless of seat height and reducing belt friction around the hips. With the pedals moved further back and appropriate deformation of the footrest in a head-on collision, finally, the risk of foot injury for the driver is likewise reduced to a minimum.
Optional enhancement of light systems.
The addition of special lights and light features previously to be found above all in upmarket models again helps to give the BMW 1 Series Coupé its premium character in terms of comfort and safety. Bi-xenon headlights available as an option as well as Adaptive Headlights including Bending Lights make driving in the dark even safer. Indeed, the combination of these comfort and safety functions is quite unique in this segment of the market.
The daytime headlight function in typical BMW style with two corona rings in each headlight unit enhances the perception of the car in normal and diffuse light conditions. Motorists following from behind, on the other hand, are warned effectively whenever the driver of a BMW 1 Series Coupé has to apply the brakes in an emergency by two-stage brake lights in LED technology. And last but not least, the high standard of safety offered from the start in the BMW 1 Series Coupé is supplemented by a third brake light integrated in the rear end of the car.
The BMW 1 Series Coupé complies in full with all standards and legal require-ments in the world’s markets, meeting all conditions for first-class results in all consumer protection tests relevant worldwide.
