Stole this thread from ls1truck. it looks like an awesome topic to discuss.

Aerodynamic Characteristics of General Motors Truck
cliff notes:
tailgate up=good
spoiler = good
bedcover= good
tailgate down=bad
tailgate off=bad
cab extender=bad

question of the day: does the saved weight of removing the tailgate actually outweigh the negative results of removing the tailgate?

discuss

 

It was discussed on mythbusters too about the tg being up actually being good. I think at the track I would take it off. Wonder how my toolbox effects the aerodynamics.

 

Good find. I did a semi controlled test on my 95 rcsb and when I put a soft bed cover on it I gained 1.2 mpg @ 70mph on the same stretch of interstate over about 200 miles.

 

i think ill break out the g-tech next weekend and do 4 runs. 2 runs with the gate and 2 without. ill be stripped down a lil for a race with a supercharged gtp.

 

What about the additonal weight of a bed cover v. increased areodynamics? Can the tailgate be removed while running a bed cover to help offset the additonal weight, or would that tend to suck air into the bed of the truck?

 

A toneau cover weighs about 30lbs I guess. A hard cover may not make as big of a difference but cruising at a constant speed, like when there is an aero advantage, weight doesn't have much affect. Weight is mainly crucial during acceleration. I think having the tailgate off with a bed cover would hurt due to the swirling as you stated.

 

This topic was discussed here before.

Weight always plays a factor in gas mileage and my fiberglass cover weighs over 100lbs - all depends on what you get. I've done tests on the highway: tailgate up, tailgate down. Never saw a difference in gas mileage at all. Even when I added the cover, I never saw a change in gas mileage. Could be the weight canceled out the benefits of the aerodynamics

 

how about a cap...LOL? Notice my sig.

 

I would like to know this too, at the track I run with no tailgate on but I still have my hard tonneau cover on??? I would say it helps on the weight side??

 

IMO the cap like yours is probably the best aero advantage overall. I personally don't care for the looks of one though. Yours is tasteful and clean looking i'd have to say.