Good Day!

I too have noticed that my trucks seem to like 65 mph or less, for good mpg. At 70 mph, it seems like you can watch the gauge go down. Sure wish I could generate some hard data.

Aerodynamic drag increases as the square of speed, so an increase in speed of ≈ 7.7% (65 > 70 mph) causes an increase in aerodynamic drag of ≈ 16.0%. Is that enough to account for how much mpg drop we're seeing?

Blessings!

Brian Johnson, #5044