Folding Mirrors?

[WMAC]

Is there any information on the aero pros and cons of folding mirrors during highway driving besides the obvious not being able to use them?

 

[StaceyS]

Gut feel, seat of the pants engineering answer: Folded is worse than not because the car was designed to have the mirrors out at speed. If they're folded, the aero shape is at an angle to the wind.

Easy experiment: Drive 70 mph with the mirrors out. Fold them in. If wind noise gets louder, you're less aerodynamic.

My car's mirrors don't fold electrically, so I just leave them out...

 

[dlv1984]

Gut feel, seat of the pants engineering answer: Folded is worse than not because the car was designed to have the mirrors out at speed. If they're folded, the aero shape is at an angle to the wind.

Easy experiment: Drive 70 mph with the mirrors out. Fold them in. If wind noise gets louder, you're less aerodynamic.

My car's mirrors don't fold electrically, so I just leave them out...

What about folded and taped over?

 

[CHG-ON]

When I go to the spray-it-yourself carwash for a quick rinse I get on the highway and floor it to get all the water off before it spots. I tried folding the mirrors to see if that would dry them off faster. It seems, from the way the droplets wiggle around, that there is actually more turbulence than when open and it makes no difference in drying them. I don't hear any difference in wind noise.