[aerohead]

Originally Posted by j-c-c

I had an idea for rear truck aero improvement, back just after the first gas crisis for a device, that would self retract, hinge to one side when its in driving position but quick rear truck access is needed, would be kept inflated by trucks compressed air system, it would need to be huge to be effective, it would be out of rear sight lines of the truck's driver, it would be light, it could be internally lit so other drivers would be aware of its location at night/dusk, it would inconsequential IMO in most accidents, unless it became detached, it would be another surface for company logos/artwork, it likely would best bang for buck if properly contoured for rear aero drag reduction. I was going to call it a "Bee tail" , and add stripes for the initial run. I got so enamored with my custom front of the truck aero device, which caused gas mileage from 5.4 to approx 7.4mpg at 70mph, I never followed up on it. Oh well. I probaly have a pic somewhere, because it was so uncommon back then, I took a lot of ribbing for it.

To the OP, I think its a lot easier to gain improvement at the front first, before going to the back, which you may have already done.

PS I believe in the US in most states, rear aero devices are not included in truck length restrictions, not sure if still widely the law.

As far as I know, the DOE/ DOT will allow up to 60-inches of rear elongation if it's for fuel economy.