Quite a few additional aero-mods: let’s look at the nubs along the roofline.
The windshield’s transition to the roof is a major point of lift/drag. Connecting airflow back to the truck is the issue. These rip at-speed above the windshield-stalled air, activating the airflow above the truck mixing out the stalled/reversing air. Big pickups sometimes have a forward jutting roofline “visor” with slots acting like a front wing, arresting the upward flow and directing it over the roof. This is my removable innovation for a similar result. >update= we had a slushy snow of a few inches that froze overnight, then used the truck for a few errands with the ice/snow on the top…about a foot behind the nubs the snow/ice was obliterated by the connective airflow, with a bit of a “windfence” roll of snow just behind the nubs. So it works!
These are special magnets with rubberized feet for cars, used for applying vinyl car-wraps. I cut the handle down to just emerge from the area of stalled air, and shaped it to cut into the air at speed above the truck and spin it down to reactivate the stalled airmass. I hoped it would keep the air flowing far enough to jump to from the cab to the shell, and it seems to have done so as the air-noise from that gap is gone.
The line at the windshield is complemented by the line of Air Tabs at the back of the shell.
These little gizmos were created with Nasa and the U.S. Department of Transportation back in the 1980’s for Semi-Trailers. Each one creates a paired vortices spinning in unison toward each other. Placed forward on a vehicle they create connective surface airflow, acting both as a lubricant against stalled air or “dirty” air (weird flows created by forward movement, tirespin, engine heat, etc). Placed at the rear edge they help create a clean break for air from the square back end, helping lessen lift, and also (there is some questioning by online aero-experts of the next part) interrupting the pocket of drag and stabilizing the rear end.
Many people note that their rear windows stay clean with the air tabs, demonstrating that the stalled/backflow of air has been broken and pushed away from the truck This may even improve gas mileage at highway speed, as some light truck owners anecdotally confirm. As speed increases, drag becomes exponential, squaring at every 5mph increase past 65, and getting crazy from 75-80. This is where they should really perform, and 75/80mph is where my mpg usually tanks, so it should be an obvious difference on our MT trips.
I’m only putting them on the shell for now, and they need a 5″ long flat space that is at most 12-16 inches from the rear edge. I had to jump from the shell to the windows. I ordered them black, and painted some of them to match the truck. On today’s test drive we headed out into a stiff headwind toward the Great Salt Lake, passing semis with no “blowby” from the windshear (one of the air-tab benefits), and experimenting with acceleration, coasting, and alignment/tracking. All were notably improved.
Placing them on the front bumper ahead of the front tires helps the unstable air at the tire and wheel well, and may reattach air to the side of the truck as well. New trucks and cars have this built into the bumper.
The airflow under pickups is always problematic- a “dirty air” mess where the stall force at the back of the vehicle can move all the way to the front, and any back-flowing air is disrupted by all the big under-hanging parts and gaps. In my imagination, these front air tabs will help. I also did something that is actually proven to help: I set foam (black) to block out any front facing gaps- with the magic of magnets! Prior to this at 70mph a roar started, became a clear low note at 75 that I could set my pace by, and faded out after 80. Gone now. I used magnets so I can remove them in the heat of summer if the lessened airflow effects the radiator’s efficiency. If I’m not hauling anything, the current opening should be fine.
This is a gap looking down on the bumper, which weakened air-ram to the radiator.
I removed the three foot whip antenna for the radio and replaced it with this 7″ stubby.
Someday, we’ll head back to the ranch and find out the full benefit. I’m hoping our 130 miles of 80mph interstate section of UT-ID sees better gas mileage. I hardly have to touch the gas now to keep her around 80. I know from today that even driving into a stiff headwind it is more stable, smoother, faster on acceleration at speed, and much quieter. E notices all these things as a passenger as well.

All decked out in her new regalia. Passenger side.

Between a few blustery snowstorms the bare metal was cleaned, etched, and given two coats of super polymer Por-15, then a spray-rubber Por-15 coating. I let this cure out for a few days, then Friday saw the center plate affixed. Saturday afternoon was the passenger unit, and today was the driver’s side and the rubber/poly airdams at the bottom for both sides.

E and I (and Nora) took it out to Saltair, traffic at 75-80mph, and there was a great improvement in handling, acceleration, and cabin noise. The bumper was meant to say “safe from deer”, but instead it hollared “off-road monster”. Now it just sings along with whatever road, or not road.

Low Center view. Each side has a lower “flexible” rubber/poly air dam for the wheel wells- held by the lower line of stainless bolts.

Standing view- it tucks under and disappears.


Corner facet profile.

All three aero-mods with reinforcing weld along the bend lines. The raised tabs (left & right top) are fortified with triangular wedges, and I extended the mid-plate with tabs (bottom of image) to grab the factory original holes on the bumper.
To bend the metal I cut a groove along the bend-line, then used boards and clamps to apply even force (so much force that I snapped off the edge of my workbench table top). Once bent these lines become brittle, and the vibration and wind-force could cause them to shear- the little bead welds rejoin both sides of the line without blowing out the thinner metal of the cut-line.
Burly male model. At L are 1 & 2 minute gestures in sienna, then run once more for brown, black, and white. 5 min at R.
10 min. x 2 The whole session seemed just on the verge of collapse, and I felt I barely made it out alive. The struggle is in not copying, but in responding to the form. This means seeing the architecture of the body within the multitudes of specific confusions, and modulating response of eye to hand with a subtle constant corrective. Sometimes this is a fun flow, and others it is a mental gymnastic that seems just behind physical coordination- while also being the inverse, a physical infirmity that lags just behind a vast intellectual problem.

A quicker set today, doing only two rounds instead of three- with brown for the first round, then black, and white for the second.
Our windstorm blew itself out and the day was nice enough to install/fit the passenger side aeromod. A bolt sheared off and needed drilling out and retapping- all because the hole in the plate was just out of alignment. All fixed.
Tomorrow’s job is welding on a few small reinforcing triangles. Along the lower drop line is a tab bent up to connect to the flange of truck undercarriage. The weld will ensure it doesn’t shear at the bend line. This is the third point of contact (held with a stainless steel bolt, not in place here, but you can see the hole), and although minimal, offers a huge amount of stability.
What is that stuff clipped to the underside of the truck’s big Shrockworks bumper?
Looks like Danger is making an aerodynamic upgrade to the yawing wheel wells of the big bumper.
It sweeps back at the rake of the under angle of the bumper.
The fitted cardboard blank.
Drawn to precise measure on butcher paper.
Cut from 16-gauge steel.
Levels of planning.
Bent to match the bumper’s angles.
Quite a few opposing bends.
The 24×24 steel plate is cut to fit as well, and installed for a first rough fit.
The Driver’s side portion is clamped in place, and the bend angles are further refined.
It must be working out, cuz Danger is drilling holes though his big bumper.
Then tapping the holes for 1/4-20 stainless steel bolts.
Everything fits together. Danger is as surprised as you are.
A bit of a change from the open wheel well on the L to the closed well on the R.
Exposed wheel / front end.
Closed wheel housing / front end. I hope the other side goes as smoothly when we have another nice day.