Topper while pulling TT help MPG?

X2 those crazy two guys on TV, showed it made no difference.best fuel mpg is to slow down stay at 55,to 60 mph.

cmcdar wrote:

Manage Aerodynamics

This is particularly crucial for trucks with open beds, where air travels into the bed and drags against the tailgate. Install a bed cover to maximize aerodynamics. The same goes for open-top Jeeps. Add a hard top or soft top (less weight) for reduced drag at high speeds.

This was proven to be untrue. Air over the cab would flow into the uncovered bed and cause an eddy effect which would then deflect air over the bed of the truck. It actually reduced drag. This is why it is better to drive with the tailgate up instead of down. A covered bed had minimal to no effect on improving aerodynamics. I believe there was even an episode on myth busters about this.
https://youtu.be/r3aqHbD-O9E

The cost of the topper will far exceed the value of any fuel savings you'll ever see. Get a topper if you need to protect things in the bed otherwise, it serves little purpose for towing.

Most of us are just guessing. You can find people who know for sure
Here (link)

++ Softopper or Bestop

They are light weight and keep contents of truck bed dry and away from loose fingers.



http://www.4wheelparts.com/off-road/gas-savings-tips.aspx

Manage Aerodynamics

Foreign objects like roof racks on the exterior of your vehicle can cause additional wind resistance and drag, especially at high speeds.

This is particularly crucial for trucks with open beds, where air travels into the bed and drags against the tailgate. Install a bed cover to maximize aerodynamics. The same goes for open-top Jeeps. Add a hard top or soft top (less weight) for reduced drag at high speeds.

Drive slower; best way to increase mpg

If you are worried about weight look at Softopper.com (not affiliated just love my collapsable cap)

Minimal ... Part of the issue is that it doesn't change the aerodynamic profile of the back end of the trailer, which is typically a flat vertical wall. Aerodynamically, this creates a vacuum at the back of the trailer, sucking the whole combination backwards to try to fill that vacuum. If you could put on a topper, and round off the back, you might get somewhere (think: Airstream, although even a little rounding can help).

I don't think it makes much difference with or without a topper. The added weight of the topper would cancel out any fuel efficiency gained by little if any improved aerodynamics. There isn't much that can be done to improve the aerodynamics of the front wall of a TT. Even a side wind blowing against the TT will decrease fuel mileage.

I have always had a topper on our pickup, not for aerodynamics, but for covered storage space.