Mr.
Valencia Pollex, electromobility has brought special demands in terms of design
and aerodynamics. On the one hand, it allows new approaches to design. On the other hand,
wheels are getting bigger because they have to carry more weight. However,
large wheels present challenges in terms of aerodynamics. As an Audi designer,
how do you manage this balancing act?
First and foremost, a wheel is a
safety-relevant component. All the forces generated by a car are transferred to
the road via the wheel/tyre configuration. Yet unlike a chassis component, the
wheel is visible to the outside. We wheel designers are thus creating something
that has to meet the technical requirements while at the same time satisfying
design aspects. The energy balance of an electric vehicle is crucial so the
focus has shifted accordingly. Previously, wheels really only had to deliver on
strength requirements. Today, we are developing and designing intelligent aero
wheels with maximum possible efficiency. After all, this has a big impact on
the range of an electric vehicle.
What is it
that makes an ideal aero wheel?
The perfect interaction of vehicle body tyre
and alloy wheel and the position of the wheel in the wheel housing. To ensure
perfect aerodynamics, we need to achieve a certain flatness so that the air
hitting the front of the car is diverted around the vehicle body without
causing strong turbulence along the sides. The paradox here is that creating
flatness on a wheel always involves quite a lot of work. A closed surface means
using more material and, in the case of aluminium, that results in a certain
weight increase. That’s why we have used plastic to create the closed surfaces
on the wheels for the Audi e-tron GT quattro. This keeps the wheel weight down.
Another factor is that, like anywhere in the energy equation, speed plays a
major role. Areas that move fast have a greater impact on aerodynamics than
slower-moving areas. This means the center of the wheel can be ignored. But
there’s a lot of aerodynamic leverage to be gained on the outer areas of an
aero wheel. In short, it’s very complex.