Air Flow Deflectors

The rear of the trailer is the place to take care of aerodynamics. I used to have a deflector on top of my Chevy Van and Suburban, didn't feel like they did anything. Flat back trailers are the worst design ever, they don't allow the air flow to detach from the trailer, so there is a vacuum behind the TT that tries to suck it backwards. I now have a 2005 Trail Cruiser that is very aerodynamic, a very laid back front that curves up from the bottom the slants way back above the propane tanks. The rear of the roof curves down and the bottom is angled in so air comes up from the sealed underside and is routed up to break the vacuum. It's also very low the the ground, which I prefer. When i had flat backs, I built a rear deflector that directed the air coming off of the roof straight down the back to break up the vacuum, the difference it made was noticeable also kept the rear end clean. So don't bother with a front air deflector