The ALPINA steering feel
At the wheel with ALPINA driving dynamics engineer Sebastian Rinke
In order to make the ALPINA driving experience a reality for each new model, the ALPINA engineers invest countless development hours and complete thousands of test kilometres on the world’s proving grounds over a period of around two years. All the drive and chassis components are finely calibrated with each other to ensure that the ALPINA philosophy and driving experience can be felt in every detail, like for example in the steering. Sebastian Rinke, steering expert from the ALPINA driving dynamics team, explains what distinguishes the ALPINA steering and the technical subtleties behind it.
ALPINA driving dynamics development
Rinke has been part of the ALPINA engineering team since 2016, and his speciality is driving dynamics. His goal when it comes to his engineering and development work is for a driver to be able to tell they are driving a BMW ALPINA just from the steering alone. “The ALPINA steering feel is pretty unique. For us, it is very important to have a coherent steering feel. Ultimately, the steering mirrors the interaction of road and vehicle. As a driver, the steering is how I get a feel for the road conditions and how the vehicle is behaving in a specific driving situation, or the lateral dynamics potential it provides. So it is vital to specifically tune the steering for each model so the actual character of the vehicle can be felt in an authentic way through the steering wheel. Our customers have very good instincts in this respect, and appreciate a responsive steering feel with precise feedback in order to be able to judge and meter the vehicle’s cornering force,” explains the automotive engineer.
So how is the character of the steering influenced? “Firstly of course is the hardware, the components that make up the steering system. Here we draw on the latest steering technologies used in BMW vehicles. BMW is known throughout the industry for its outstanding steering. Secondly the steering set-up. Here we can define, for example, how much force the driver has to exert for the steering movement. This is known as ‘hand torque’ in the industry. Thirdly, the influence of other chassis components. Various chassis components influence the effort required for a steering force and the feedback from the road to the steering. All these areas are closely interconnected, therefore the engineering work is always entwined too. All of the various driving dynamics and testing teams are in constant exchange with each other in order to achieve a harmonious interplay of all the components.”
True hand torque
The fact that the steering set-up always follows the chassis engineering is part of the ALPINA philosophy for Rinke: “Our goal is to generate true hand torque or, to put it another way, we want the actual dynamic qualities of the vehicle to be mirrored in the steering feel as authentically as possible. Some of the ways we achieve this are the ALPINA specific tyres and a very rigid chassis. Let us take the BMW ALPINA B8 as an example: here we favour more rigid support bearings, reinforced structural components in the body and adapted kinematics on the front axle. The components used on the rear axle include forged lower wishbones with more rigid mounts. None of these chassis components are directly involved in the steering, but they provide optimum vehicle support and a better connection between road and driver, and this is clearly felt in the steering. Ultimately, we want drivers to be able to feel the actual lateral dynamics in the steering, and we don’t want to distort this with an artificial steering set-up. This is the only way for each model to get its unique, authentic character.”
COMFORT, SPORT, SPORT+
On the BMW ALPINA B8, the driver can choose between three steering modes. “The right mode depends entirely on the driver’s taste and the particular driving situation. For smoother steering, especially in everyday driving situations, COMFORT mode is recommended. For a high hand torque, SPORT mode is the one. We attach great importance in the engineering to a perceptible spread between the various modes. In SPORT+ mode, the steering gives very direct feedback. I immediately feel in the steering wheel how much lateral force the vehicle is building up, which means I can turn into bends very precisely during dynamic cornering manoeuvres without having to readjust,” explains Rinke.
Integral Active Steering
Another special feature of the steering technology in the BMW ALPINA B8 is active steering on the rear axle. BMW Integral Active Steering is standard on the Gran Coupé. At low speeds, opposing steering locks for the front and rear wheels greatly increase manoeuvrability. “What we are talking about here is a virtual shortening of the wheelbase. The technology is especially advantageous with large vehicles like the BMW ALPINA B8 since it significantly reduces the turning circle. Manoeuvring and parking in confined spaces become easier, the vehicle feels more agile,” explains Rinke.
At speeds above 70 km/h, the wheels on both axles turn in the same direction. “This has an impact on the driving experience, especially when changing lanes on the motorway. The fact that both axles are steering in the same direction means that both also build up lateral force without any time lag. The rear axle does not follow the skew of the front axle, rather the vehicle glides sideways. As a result, roll dynamics are reduced and the vehicle reacts more confidently with greater driving stability. This is a major plus point, particularly at the high speeds the BMW ALPINA models traditionally allow.”
High speed stability
ALPINA also focuses on safety at high speeds which is where the steering is also relevant. “At high speeds the steering is additionally dampened, in other words the steering dampens fast steering movements more strongly as speed increases. The steering is then stiffer, no matter which mode the driver selected. By doing this we prevent the vehicle lurching or penduluming during energetic steering interventions in the high-speed range.”
On the test track
High speed driving manoeuvres or manoeuvres with large steering angles are tested on closed proving grounds – primarily on the BMW test track in Aschheim or on the proving grounds in Miramas and also at the Nürburgring. Here the driving dynamics engineers have all the options available to test a wide range of driving manoeuvres in a safe environment. “When it comes to the steering set-up, in particular the small steering movements from the centre position are critical. This is the range predominantly used in everyday driving, so it is essential that a BMW ALPINA provides authentic feedback here too, and conveys the ALPINA steering feel to the driver. Our testing spectrum therefore ranges from the speed-calmed zone, to the supermarket car park to the high-speed test circuit.”
Fuel consumption and CO2 emissions*:
BMW ALPINA B8 Gran Coupé*: Fuel consumption NEDC correlated combined 11.1 l/100 km / 25.4 mpg, CO2 emissions NEDC correlated combined 254 g/km, efficiency category F (Germany), fuel consumption WLTP combined 11.9 l/100 km / 23.7 mpg, CO2 emissions WLTP combined 270 g/km.
*Stated fuel consumption and CO2 emissions are measured pursuant to EU Regulation 715/2007 in its applicable version. For more information see www.ALPINA.de/DAT-Hinweis.