Pickup truck partial tonneau

[JeffD]

I built a half tonneau cover for my pickup truck and thought it might be helpful to share how it was done.

The first thing was to remove the truck box behind the cab, so I wanted to make sure I had some area that was covered and dry. I also wanted to make it semi-easily removable to haul larger items when necessary. It ended up being 3 pieces: a false floor and a forward wall for the “trunk”, and the cover itself.

Deck screws (only partially screwed-in) are used to keep the floor off the bedliner so that rain water from the uncovered portion of the bed can run underneath. 2X2’s stick out from the side to fit into slots in the bed-liner, keeping the floor from moving around.

2X4’s were bolted to the interior of the tuck bed rails using ¼-20 nuts and bolts. 2x2’s were screwed into these to engage the forward wall and help support the cover.

The forward wall is held in place at the bottom by slipping into angle brackets on the floor and at the top in slots created by the 2x2’s on the side rails. The top cover is bolted to the top rails using a single ¼-20 screw on each side and hinged.

This seems to be working pretty well so far. The uncovered area is usable by reaching over the side and I have a little trunk to keep things dry and out-of-sight which is accessible by lifting the cover. I can remove it all (except the 2x4’s on the side rails) in manageable pieces with just 2 screws.

[deejaaa]

i'm confused.

[aerohead]

The forward wall will prevent the low pressure of the locked-vortex to communicate to the inner face of the tailgate,which is a critical factor in the 1/2-tonneau performance.
You might try it with and without and see if it shows on the radar.

[deejaaa]

if and when i get the truck back on the road i will. what are the gains?

[JeffD]

Deejaaa, I'd be happy to clarify if I can. If your confusion is on why a half tonneau, then aerohead is definitely the guy to talk about that. Unfortunately I don't have data on performance with and without since I didn't isolate the change, but I suspect it's different depending on the truck. I've also seen folks reference anywhere from 30% to 60% coverage. I'm thinking optimal coverage is probably geometry dependent and may change with the truck as well. I could have done a better job testing, sorry 'bout that.

Aerohead, I did find a copy of the GM patent and it did clearly show that having a wall hurt performance as you say. Even so, I'd like to keep it for practicality. I suspect the stuff in the "trunk" might remain dry without it, but I'd still like to keep items out of sight. I am also considering adding a lock someday. The wall is aft of the front edge of the cover by about a foot, so I was hoping that would help - the low pressure acting on the forward wall instead of the tailgate.

While writing this, you got me thinking about 2 things though: 1) How well does it have to be sealed for the low pressure to have an effect? and 2) I wonder if using one of those mesh tail gate things instead of a wall would improve performance while keeping stuff from moving forward while stopping.