Hey all, I just bought a '98 F150 to pull my toy hauler. The trailer isn't too heavy, but it does have a fairly large frontal area. I was wondering if any of you had any thoughts about whether a fiberglass shell for the bed would improve aerodynamics enough to make a difference in gas milage when pulling the trailer?

 

Hi Motorob

Your first post.....Welcome!

Used to be alot of controversay about the open bed on trucks..

Dont know what the latest is.. Sometime ago i read about wind tests done by the big 3 on their trucks. The outcome of that, they didnt agree with each other....better to leave tail gate down, up, put shell on bed..better mpg.....Was interesting, but confusing.

IMO...the shell on bed would allow air to flow across smoother, but is it gonna hit that frontal area on trailer harder, dont know?

Ever notice the air scoops on big rig tractor roofs, allows some air to flow over frontal area of trailer their towing. Also see them on trucks pulling rv trailers. May help handling/ mpg.?

Maybe someone here can give you real life figures...mpg etc.
You might try web site irv2.com

Gotta figure if it does improve mpg & handling, is it cost effective?

Good luck. OT

 

I figure that I'll probably get a cap sooner or later, but improving gas milage a mpg or two would be a good argument for sooner rather than later. I'll checkout irv2.com... thx

 

I have a cap, but I don't pull anything bigger than a little flatbed trailer. I can tell you that it didn't make much of a change either way as far as mileage goes. If I keep my foot out of it, I get around 18-19. Foot firmly planted and I only get 16.5-17. So even at highway speeds, the cap didn't help much. Helps great with traction in the winter though!

Justin

 

If the cap is able to direct the airflow over and around your trailer, your mileage MIGHT get better. On the other hand, the extra weight might offset any aerodynamic savings.

If you're going to be towing 90% of the time, then doing something might be worthwhile. If you're not going to be towing that much and will be using the truck for just getting around, then I wouldn't worry too much about it. In that case, just make your decision on what's best for your needs. If you need a cap because of the secure space inside, then get one. If you want to get a cap because you think it will increase your mpgs, then I'd think twice about it. Besides, the cost of the cap might be a lot more than the price of the gas you'll be saving. I can't imagine a cap saving you between 1,000 and 2,000 (or more) gallons of gas.

 

I just bought a new cap, I ran with a fiberglass tonneau for 2.5 years so have goo d mpg data that way. Just now on my second tank of gas with the cap so it's a little early to tell. But, My firs tank with the cap was 16.7 mpg about 50% highway at 65mph. This is quite good for me, previously I was getting 16.0 to 16.3 same type driving. Time will tell. My total mpg for 2.5 years is 15.5 mpg, about 20% highway.