In several interviews, Mr Biermann, head of development for M automobiles, has heaped praise on the M Servotronic system used in the new BMW M3 Sedan and the new BMW M4 Coupé. What is it that justifies this evaluation, from your point of view?
EPS systems can often convey a somewhat synthetic feel, and this is precisely what we did not want. The driver of the BMW M3 or BMW M4 should have a good sense of the nature of the road surface. He wants to be able to feel when he is driving over a drain cover in the road or when the surface material changes. This steering is responsive enough to convey these impressions very clearly when we began its development, I didnt expect it to be able to do this to the extent it does.
Similarly, the driver is able to immediately feel any transitional responses in the steering, the moment he enters the marginal zone when the car begins to skid due to over or understeering. This makes it possible to drive the car very precisely at its limit: not only by DTM racing drivers although Bruno Spengler and Timo Glock are very impressed with the steering.
What was the greatest challenge in developing this steering?
The biggest challenge was to ensure that the industrial production suited the EPS steering in the way in which we developed it. The steering has very good responsiveness as far as the road surface is concerned. However, this precision places great demands on the production process. It requires a very precisely produced steering system and, in turn, precisely turned out parts and components.
This driver is able to choose from three different characteristic curves for the steering. Why did you decide to provide this capability?
Our customers have very different tastes. There are drivers who prefer light steering while others prefer to use more manual force. This is why we have included three steering mode settings: Comfort, Sport und Sport plus. Changing from one mode to another will not result in any functional differences and will not, for instance, cause any change in the quality of the steerings responsiveness. We also have racing drivers in our department; they prefer to apply the Comfort mode curve while the adaptive M suspension is set to Sport plus. It is really up to the driver to decide which choice best suits his personal preferences.