Does lowering the tailgate on your truck improve your gas mileage?

Question

i drive an '82 toyota 3/4 ton with a 5-speed manual transmission and i drive about 60-70 miles a day averaging about 70 mph on the freeway and around 40 mph on surface streets. would lowering my tailgate improve my gas mileage?

Answer 1

Nope, the air going over the close tail gate acts like a "hatch" on the back of your truck which lets air go smoothly over that. So your truck would be more aerodynamic with the tailgate up.  

Answer 2

there have been many tests on truck with the tailgate down or up. Having it down does not improve the gas mileage.

Answer 3

no.  it can actually increase it and will weaken your truck.

here's why.  when you are going down the road with the bed shut a high pressure builds up in the bed and most of the wind goes over it instead of through it.  this effectively shrinks the size of the vortex behind the truck which decreases drag.  this has been repeatedly tested in wind tunnels and on roads with full instrumentation, trucks are built to have their tailgates on.  if you want to improve that flow of air, get a bed cover for the truck.

it can also weaken your truck.  just as your doors being closed are an important strength structure for your truck, the tailgate holds the back of the bed together.  when it's removed or left open your bed flexes more and is more susceptible to breakage.

Answer 4

It does help with the wind drag caused by a closed tail gate...but you will get better MPG if you slow up just a little. Do not exceed 60 MPH and that will help better than lowering tail gate.