Quote:
Originally Posted by mpg_numbers_guy
You will likely notice more of a benefit with rear wheel covers than front wheel covers. I removed the front wheel covers from my Civic when I had it and left the rear ones installed, and didn't notice and discernible fuel economy loss. My theory is that rear wheel covers have a larger effect since they're near the rear of the car, and any flow disruption near the rear of the car will add more drag.
|
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.