Aerodynamic Effects of Different Tire Models on a Sedan Type Passenger Car
Journal article, 2012
Targets for reducing emissions and improving energy efficiency present the automotive industry with many challenges. Passenger cars
are by far the most common means of personal transport in the developed part of the world, and energy consumption related to
personal transportation is predicted to increase significantly in the coming decades. Improved aerodynamic performance of passenger
cars will be one of many important areas which will occupy engineers and researchers for the foreseeable future.
The significance of wheels and wheel housings is well known today, but the relative importance of the different components has still
not been fully investigated. A number of investigations highlighting the importance of proper ground simulation have been published,
and recently a number of studies on improved aerodynamic design of the wheel have been presented as well.
This study is an investigation of aerodynamic influences of different tyres. Two different tyre models were investigated in
combination with three different wheel designs using the Volvo Aerodynamic Wind Tunnel; including moving ground and rotating
wheels. In addition to force measurements, flow field investigations were also performed using both surface pressure probes and 12-
hole pressure probes. The tyre sizes investigated in this study were 215/50R17 and 215/55R16. An investigation of changes to the tyre
geometry for 215/55/R16 tyres was also performed using two high speed cameras in the wind tunnel.
Results show that different tyre types have a significant effect on not only aerodynamic drag, but also on lift to some extent. Drag
differences between 5 – 10 drag counts were measured depending on wheel and vehicle configuration. It was also concluded that the
drag difference between tyre types was dependent on wheel design. The flow field investigations showed noticeable changes to the
front wheel wake structures as well as significant changes in the rear wheel and base wake structures. Investigations of the tyre
deformations showed changes in wheel lift, as well as radial expansion and axial compression correlating with the observed drag