I wouldn't waste money on those. I tried those at my previous company. Didn't see any measurable difference in mpg.
In all honesty I don't see how the flow below make that much of a difference on the cascadia evolution platform. The side fairings are kicked out to push the air past the wheels already. I'm not saying they don't make a difference I'm just saying I don't see how.
I swear we should be paid for fueling these reefers at flying j. Unless its 1 am, fueling is a nightmare. I spend more time waiting to fuel than I do fueling.
My dispatch on this load says to be here today at noon. I get here and check in and was told my appt. was for yesterday. So, now, I'm a work in with 5 trucks ahead of me for work ins. All with the same issue. Fry's says yesterday and dispatches say today. Not sure who screwed the pooch on this one, but my guess would be Fry's.
So what happens when the wind hits your tractor at a 45 or more angle? The coverage on the wheels and in between helps keep that air from getting under your frame.