Pickup Canopy

[miles]

We have a 2003 Toyota Tundra, rated 15 city, 18 hwy. Long trip planned with scooters in the truck bed.

1) If I were to delete the pipe rack and add a canopy, what kind of mpg change should I expect? Does anyone have an educated guess?

Obviously, a tonneau or boat tail would be better, but wouldn't leave room for the scooters.

I know that mythbusters tested tailgate up, down, mesh tailgate, tonneau, etc.

2) Does anyone know where I can find the data from their tests?

3) Did they also test a canopy?

Thanks,
Miles

[aerohead]

Texas Tech did the research and published in 1988.Gate up/gate down was within a percent.It did loose 1 %.Someone did post a link to the Myth-busters video segment,and if you'll go back to earlier post here at the aero forum I bet you find it.If the bikes are taller than the roof of the Tundra they'll tear the air to pieces.If you buy a cap which is taller than the cab you'll be streamlining the flow,but adding sectional area which will tend to cancel out the streamlining.Pulling the bikes behind on a trailer,with the tailgate up would be better.If you've seen "The World's Fastest Indian" you might rig up a device like Burt Munro used behind his car in New Zealand.The front fork is pinned to a bumper-mounted bracket,and held in place by the axle.The bikes hide in the wake of the Tundra like a NASCAR draft,with virtually no windage.With the bikes out of the bed,you could just cover the rear portion of the bed with a half-tonneau,a design patented by General Motors,and claimed to actually have less drag than a full tonneau.A bit more trouble having to deal with the front wheels of the bikes,however probably your cheapest travel.By the way,a straight back topper would give you about 5 % better mpg.The tonneau is also good for about 5 %.Bondo's aeroshell gives 20 %,my now-deceased aeroshell was good for a 13 % improvement.Happy Trails!