Angled tonneau cover questions
 

So my tonneau cover is on Order. Wife heard me yammering about tonneau covers and mpg’s. Long story short an Arrocap/Shell is out of the question for me i tow with a 5th wheel and gooseneck with lots of my friends, colleagues, church members, aquatintces etc moving for some reason lol. So i would like to use an angled tonneau cover like Jacob did with his old 1983 diesel pickup. Coming up about halfway up the back of the cab (allows me to see or back window a bit more) then either going to top of tailgate or higher.

What is the optimum degree of angle for reducing drag? Seems steeper is bad, and @Big Dave Mentioned wanting to go 10-11 degrees from top of cab and ending about 8inches above his tailgate?

Just looking for something telling you how to find the best angle for a tonneau cover. I can cut to triangle shaped sides and bolt to inner bed rails and maybe like a two piece lid or etc.

https://www.google.com/amp/www.instr...famp_page=true

Read This

Page 85 (of paper)

Yer Welcome

Thank you very much.

Dag nabit Bobby lol.
I started reading that a few days ago but I missed the summary of the aerocap. I assumed it would go way to much into detail on the side slopes, vs just a simple degree chart for efficiency:( So seems 12 degrees is the most efficient for a truck. Once truck is back from the body shop I’ll take some measurements and I’ll find some sort of decent software to show you guys some mock ups. I’m hoping to go no more than half way up the rear cab so I can keep visibility, plus I have a 6ft9in bed vs the full long bed etc

I’ll probably use ms paint for a few mock ups because I plan to copy the diesel in the link. I tend to use my bed the most when I think I wouldn’t lol.

bondo was working on a semi box cavity that attached to the rear of the cab. Not sure where it is in the process of production. Maybe you could give him a PM. ;)
http://ecomodder.com/forum/showthrea...ote-35533.html

Lund made a racer cab spoiler that you could borrow from the design. It was discontinued and very hard to find. :(
https://www.pickupspecialties.com/lu...er_by_lund.htm
https://www.pickupspecialties.com/lu..._racerback.jpg

You can see something similar with the Toyota T150 concept (became the Tundra) which was bed-based instead of hanging off of the cab. ;)
https://s3.amazonaws.com/s3.timetoas...oyota-t150.jpg

Maybe these examples will give you some ideas in which direction you can go. ;)

Do to my non existent fiberglass/plastic molding skills I think im going to look up for the forums for triangles and copy the 1983 diesels angled cover like the picture. I sent him a pm asking how he mounted the plywood triangle pieces so hoping to hear soon.

Big Daves reportedly was just a little less than 25 degrees but he wanted to go to 11-12 degrees in the future but no updates so far.

I should have my tonneau cover this Friday and I'll have little over 2k miles to test and see if it makes a difference for me. I'll be driving from Yuba City CA to Sandpoint Idaho around Christmas.

Done the drive a dozen times but I know the snow will hamper my results but even a 1mpg improvement will be noticeable and around $60 savings in fuel lol.

Is there a link on the forum for adding pictures from your desktop or only form file hosing sites? I wont pay photobucket a single penny for reasons.

The Lund spoiler isn't what you want, the tapering lip that extends and lowers the trailing edge of the Toyota's cab is more suited to what you're trying to accomplish.

As to making partial gains with a box cavity cab wall extension, dunno. I don't think I've seen anything on that, but it sounds like it's at least worth exploring.

Im definitely new to ecomodding but after reading on the two 7.3l diesels id like to emulate I learned what I would like and about where I could be on freeway economy.

tonneau cover should bring me at least 1mpg more on highway so 17.7 to at least 18-18.7.

Air dam seemed .76mpg max! not a lot but for my truck its the least invasive. so theres 19mpg

in the future seems a 12degree angled tonneau cover copying the guy below:

Vehicle Efficiency Upgrades: 30+ MPG in 2.5ton Commercial Truck: 6 Steps (with Pictures)

This should bring me to 20-21mpg which is my goal for now.


I eventually plan on adding some little mirrors and folding my tow mirrors in unless towing of course.

I cant see myself adding wheel skirts, or belly pan as I go in the woods quite often for hunting/camping but on the freeway the mods should bring me to 20mpg at least.

Big Dave had $4k for the gear vendor, and probably $1k for higher gear ratio in the rear end and my 4x4 model doesn't have a high enough gear to warrant the cost. Plus the two fellas im trying to mimic have manuals so im already at a -2mpg comparatively. I even got a shift kit and a tuner that honestly will help but its not going to be tremendous.

it allows me to adjust firmness, pressure, speed, torq lock etc...

I don't pay a penny fer Photobucket either but I have found that using the ~original tag after the .jpg tag will allow you to post piccies. Example...

http://i677.photobucket.com/albums/v...e.jpg~original

lets give this a shot lol....

this is basically what I want to do but I want to pretty it up and make it somewhat simple to remove with a hard lid

If you do attach it to the cab, I would highly recommend mechanical fasteners over tape, VHB double sided tape, or even glue/epoxy. If yer squeamish about drilling into yer cab, yer gonna have to find a strong method of attachment. Even some bracing to aid in keeping the form from distorting from the air flow. ;)

Bed based will require either a cab gap (like the T-150 has) or a sliding cover as the truck flexes. My front top/side covers on my aero cap slides over the cab. ;)