Quote:
Originally Posted by Vman455
I would be hesitant to guess that. I came across this passage in one of the textbooks I read earlier this year and underlined it since I was surprised by it:
"The front wheels contribute the bulk (about 65%) of the total wheel drag in cars because the rear wheels are typically in the wake of the front wheels, only experiencing some of the vortices generated by the front wheel interaction with the car-body air flow, and the lower edge of the trailing stream flow from the front wheel (Fig. 5.8)" [Obidi, T.Y. Theory and Applications of Aerodynamics for Ground Vehicles, (Warrendale: SAE International, 2014), 122].
Also, recall the McLaren Speedtail, which has wheel covers on the front wheels only--something the design director said in an interview was necessary to reach their top speed target, while rear wheel covers were not.
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Front wheels will contribute overall to more drag than the rear wheels yes, but I was talking about aerodynamically from the side. I probably should've been clearer. Poor wheel aero affects the attached airflow to the side of the car, but at the rear there isn't any more car length for the flow to reattach, which is why I was theorizing that rear wheel covers would make a larger difference. In terms of overall drag, including under the car and from the width of the tire, then yes, definitely more drag is caused by the fronts since the rears are in the wake of the fronts.
Interesting though about the McLaren Speedtail. Did the design director say that they were for aero, or downforce? although I can't imagine how smooth wheel covers would help downforce at all.