This weekend I had to drive over to Latrobe, Pa. to help my in-laws with getting my wife's great-aunts house together to sell since she just recently passed. I was also there to pickup her new fridge that she bought before her passing and replace my circa 1970s fridge with rich corinthean leather trim. Anyway I removed my fiberglass tonneau and headed up. I normally get 15-17 mpg highway with the tonneau and I only received 14.2 highway w/o it and I even drove slower (the speed limit) on the way there. So if you guys want better gas mileage get a tonneau. Just a thought. Worst thing was is that I only lost about .5 mpg on the way back with a fridge, a bunch of landscaping and a couple tables in the back vs. empty bed with no tonneau on the way there.

 

is this a trip that you've taken often? could be that you had a headwind on the way up and tailwind on the way back, explaining the mpg difference with a fridge in the back. it could also explain the drop in milage. I have a tonneau on my other truck an I have never been able to say "yes it does help milage" in the 2 years that it's been on the truck.

 

When i bought my tonnue cover new, they guy told me i would see an 11% increase in gas mileage, and i knew he was full of u know what......anyways havent seen a noticable difference in mileage....although yours is fiberglass...mine is the HD Vinyl, wind is THE FACTOR when it comes to gas mileage.

 

the clearest benifit of having mine on the '00 was the lockable storage... needless to say, i'm looking for one for the '05.

 

I travel to Pittsburgh about once a month to see family. I was calculating the drop w/o the fridge on the way there vs. my normal highway travel with the tonneau cover. I was just stating that I only lost .5 mpg with all the weight in the back.

 

I personally think the fiberglass tonneau looks better than an open bed, and it actually does help some in mileage.

 

Definitely. My truck looked naked w/o it and the bed looks tiny now.

 

I read an article about this subject not long ago and it was proven in tests that the cover on the bed would increase gas mileage, albeit how slight. Some might see more benefit than others but the tests showed there was an increase. Oddly enough the same test showed that the old "tailgate down" or off trick actually decreased mileage.

 

I really need to get one...

 

I dont know if I buy the tailgate down one... a friend of mine always had trouble going over the grapevine (hiway summit) in CA with the gate up, told him to try it with the gate down and he said it was a lot better going over the summit. his truck didnt have to work so hard. his truck was a toyota 4x4 truck.