[instarx]

Hmm. A lot of reasons posted as to why the smooth wheel covers here aren't really worse than the alloys for smoothing airflow, despite the clear visual indication that they are. On this car the smooth wheel covers clearly disturb the airflow more than the alloys.

The car is the car, and the tufts are the tufts. If the car has slightly flared fenders then those are the conditions of the test. Many cars have those. I find this interesting because it shows that smoothing airflow along a vehicle isn't as easy as it appears it would be - even the most accepted of mods may result in a loss and not a win.

Are the alloys a "fan blade" type that might be sucking air into the wheel? That could be a factor in why the airflow downstream of the alloy wheel is less disturbed.