Quote:
Originally Posted by ecomodded
I remember reading that a car would gain 2-3 mpg with wheel skirts so taking the size of the wheel wheels in question i upped the value to 4-5 mpg. I must admit it sounds unreasonable, I am going to change my estimate to 3-4mpg  |
And this is why MPG is a stupid measurement for fuel saving.
Going from 30 to 33 mpg will save you 3 gallons in 1000 miles.
Going from 15 to 18 mpg will save you 11 gallons in 1000 miles.
3 MPG change does not mean the same thing on one vehicle as another.
If the wheelskirts were to save about the same amount on the suburban as a 30mpg car the difference would be 0.5-0.7 mpg, not an insignificant amount on a large vehicle.