[Concrete]

The story-

been reading at Ecomodders and slowly modding truck
here is where the truck is at for this testing:
Tune up, Bed cover, E-fan, high end tire pressure, upper grill block.
Scan gauge, driver adjustment

with wheel covers I started to see +30mpg regularly - streight & level - A milestone!
but wheel covers were not suppose to make much difference, right?
I had only put them on so my wheels were not cupping air into the wheel skirts I intended to make
I had not done much aero testing so I was starting from scratch

So I spent an hour and a half driving around trying to get good high speed data
A-B-A-B-A-B.... it became a test of will - nearly 100 miles later I had developed a method
and I got three runs I trusted A-B-A
31.6
30.6
31.7mpg
not very rigorus, but I had convinced myself I had ~1 mpg drag reduction


The Method
Here is where I better explain what my proceedure looks like

basically it is a running start with curise control set at 65mph
scan gauge average calculator is reset at a milage sign post
route is 4 lane interstate - level but with two over passes - gentle curve 90 degrees
outbound is 3.3 miles - return is 3.1 miles - nearly symetric
clover leaf turn around is not in test to reduce the varience I was getting
nearly symetric path back for a two way run - scan gauge reset for return trip
all controls are set the same - vent on - fan#2 setting - radio & lights but nothing else
tested late at night for consistent temp and low traffic
tested in no wind conditions (yes it can happen in Kansas sometimes)

"wasted" a lot of gas - but now have a great baseline for future improvements

I should have stopped - But I didn’t
I knew to convince the Ecomodder community & thus get some data out on wheel covers
Even more testing would have to be done - so I did it

Data to follow