Temporary plywood tonneau cover
 

I'm going to need to make an empty 350 mile trip down to LA shortly.

I'm tempted to take a sheet of plywood and strap it down on some 2x4 legs to be level to the top of the box. Would it yield any practical mpg gains?

The box is wider than the 4x8 sheet, so there'd be 2 long open gaps down the length of the box. It is specifically a quick and dirty temporary 30min setup made of scrap wood that I have lying around. It'll remove since I'm hauling stuff in the back most of the time.

Any of you guys try this and see any benefit/difference?

thanks

I doubt you would see enough if any MPG gains to make it worth the trouble.

Just a goofy thot" - Duct tape a couple shower curtains (Dollar Store) together and tape them over the bed. REAL GOOFY THOT = CLEAR shower curtains taped together and taped to the top rear of the cab and tailgate at the back <[ "fastback truck"]

According to Myth Busters covering the box doesn't help fuel economy. They covered this twice in different shows and got the same results each time.

I doubt you'd see enough gain to pay for the lumber and hardware.

I've watches the same "Myth Busters" also. I can see the plywood 'cover' for looks but not for economy. There is a vortex in the bed when it's moving < works like a roller (wheel) and the majority of air rides over that]. Like an 'eddy' in a river.

Well, I finally tried this since I had nothing to lose as an experiment. I made a 700mile round trip out to Reno up and back on I-80 with a 6ftx4ft sheet 3/8" plywood that I've had sitting in the garage. I screwed it down on 2 pairs of legs made of some scrap 2x4's I was about to toss. I hacked the whole thing together in about 20minutes. I mounted it so the top was flush along the top of the box.

Anyways, compared to 4 near-identical previous trips around the same time of the year, this time I averaged about 0.8~1.5mpg better, hand-calculated, gas-station to gas-station on 3 fill-ups. The 0.8mpg was going there uphill, 1.5mpg was on the way back down. I drove 65-70mph most of the way.

Not a big deal, but if I'm averaging 14-15mpg, that works out to be 5~10% improvement, so of the $200 or
so fuel I spent on the trip, it works out to be about $15 savings. Not bad..that pays for my lunch.

For kicks, I'm going to try this again on the next trip just to see if I'm not imagining things.

Needless to say, wife was rather miffed and said it was ugly; I said it was just an experiment that could be disassembled in 2 minutes if needed. Now after seeing the mpgs, she's approved and is trying to convince me to get a real cover. :-)


So I'm wondering if any of y'all can or have tried this and see what you experienced... if you do it, make sure you strap it down real good....

aquaman - Just another thought, use luan. It's 1/4" mahogany and can look mighty fine IF you can pick thru the stack to get "the right piece". Some sheets have 'blems' and some looks good 'nuf for cabinet work. < strong + light weight. With a couple coats of urethane it sorta sparkles. OR with a bit of filler + sanding it can be painted to look like a fiberglas cover. I made one a while back for a friend, matched his truck with rally stripe. < custom + cheap. I have plans = for a short/narrow bed - can be modified to fit any. Pneumatic cylinders + 2 latches @ back + can have a spoiler if wanted.

Tonneau covers work if you have stuff in the back that cause turbulance.

It especially works if you have a truck bed tool box, and on my old truck the tool box lost me 5 mpgs. I gained 6 back with the tonneau.

So if the bed is clean and empty then no effective difference will be noted.

I like my wooded tonneau cover. It's all plywood with some 2x3 across and 2x4 on the sides for re-enforcement so anything can stand on it without going through.

It splits and lifts up in the middle also.

Loved it! Also added a good amount of weight over the back wheels for winter.

http://i607.photobucket.com/albums/t...n/003-10-1.jpg

IDID-J, Good work. I did similiar but lower profile and for looks as well as use. Boats are an 'interest' of mine - a thin layer of nylon + resin makes a boat/tub-like finish of done right. I used 1X4's and 5mm luan, slight arched top / rain runs off.Finished, it looked like an expensive custom cover but a LOT LESS $$. A friend of his wanted me to make a "cover" for his S-10 that would make his p/u into a fastback for racing. They both thought I was a bit 'tilted' when I told them to use a corvette roof.

I thought about putting in a painted plywood tonneau not for mileage but rather to keep the wet off my wooden bed. I thought about consulting my grandpa. He's the master of homemade stuff like that. On his Mazda pu, he made a hinged one that was painted, used bed corner anchors rigged with pins and padlocks to hold it down, and had rails along the sides of the long piece to eliminate flexing.