As well as the drivetrain, the rear-end and the rear suspension are the two areas where the BMW i Motorsport engineers had the greatest leeway for their own developments. While the chassis, battery and tyres are standard Formula E parts, in order to keep a lid on costs, the engineers at BMW i Motorsport designed the rear axle, including suspension and shock absorbers, themselves and integrated the drivetrain in the rear part of the car. As each drivetrain has its own individual properties, each team is responsible for integrating the drivetrain into the rear-end structure of the cars and finding a cooling set-up that suits these properties.
The team can configure typical set-up parameters on the chassis of the BMW iFE.18, such as spring rates, anti-roll bars, ride height, toe and camber. The chassis set-up plays an important role in achieving maximum mechanical grip on the tarmac surfaces of the street circuits, some of which are very uneven compared to permanent racetracks. It is also important that both the chassis and the rear-end structure are robust enough to cope with driving over aggressive kerbs and light contact with the barriers on the street circuits used in Formula E.
The so-called Generative Design process was used when developing various components. This made it possible to directly derive the design of the components from the load cases, with the assistance of computers, to incorporate the experience and expertise of the BMW i Motorsport engineers, and then to produce the components from aluminium using a 3D printing procedure. In the case of other components, this combination of know-how and technology has made it possible to very efficiently integrate various functions, such as in the cooling circuits, in very few parts.
The many years of experience possessed by BMW i Motorsport engineers in the development and production of fibre-reinforced plastics really came into its own in the design of the rear-end structure. The structure is not only very light, but a wide range of functions have also been integrated directly into the structure. The crash load requirements of the sporting authorities were also met in full and without any problems at the first attempt.
The topic of sustainability also plays a major role in the development of the BMW iFE.18. BMW i Motorsport engineers are working very closely with their colleagues in production to increasingly integrate renewable resources in suitable components.