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. ;)

no drilling in the cab for me, but I think I can make flap that bridges the gap between the angled tonneau cover with the conveyor belt and some aluminum strips/brackets. That way its rubber and won't damage the window its resting on but re-enforced with some aluminum tabs and arms to keep from flapping up/down with heavy winds.


SORRY for the paint picture lol.... but hope it gets the point across lol.

Yer gonna want something in between the glass and the rubber so it doesn't scratch or break the glass. Maybe also make the rubber strip much longer and bend it down at the glass so it can flex accordingly? ;)

I don't see much of a way around your [wife's] prejudices.

If you came to us before the fact, we could talk about half-tonneaus, boxed cavities and perforated base plates. Those discussions are now moot.

All we have to work with is a picture of someone else's tonneau cover and a misguided assumption that a 3D flow field can be reduced to a simple 12° angle. By all means go ahead and [just] do it. That would be classed as wake filling. Base pressure is exerted against the rear face irrespective of it's angle, you'll just spread it over a larger area.

Here's is what I would do:

http://ecomodder.com/forum/member-fr...02-5-26-32.png

This is half-way between a half-tonneau and a spoiler. The line from the back of the cab to the top of that 3rd 4th taillight is...

wait for it...

12°.

The tonneau was 50/50 I need something to cover the bed and keep stuff mostly dry during trips. Worst case for long drives without needing the bed I can cab up a half cover for the bed and a custom headache each with a fin for the rear cab spoiler.

But the 83 f250 getting a solid 2mpg from his fabbed angled tonneau, I figured worst case I’ll gain something. I know the pdf and computer simulated tunnel is conjecture but tonneaus half or full seemed to help pickups on freeways above 45mph at least. I don’t think I’m up for a rear spoiler though. Looks like “not your average pizza delivery lol”


To my wife’s defense, if I wanted to build and aerocap and drill holes she would help me do it. But I’m not that dedicated to ecomoddong my truck yet. But if I can mod the truck to just be better, and not loose to much useability I’m
Game. She is surprisingly supportive of anything I do as long as I actually research and do some planning etc.

Pardon my presupposition.

It folds in half? Here's a golden oldie:

https://i.imgur.com/Who5l.jpg

edit:
Camping World Cup trucks use a simple spoiler that follows the 12° rule.

http://www.rantsports.com/nascar/wp-...ty-dillon2.jpg
http://www.rantsports.com/nascar/wp-content/slideshow/2012/11/top-five-future-sprint-cup-series-drivers-from-the-camping-world-truck-series/medium/ty-dillon2.jpg

No reason why the spoiler couldn't be clear plastic, and/or retractable. It doesn't need to be a rectangle, a half-octagon or curved arc would have less frontal area, and conform to the vortexes that stream off the back of the cab.

with the picture of the white pickup, from the front of the bed(essentially the bottom of the rear of the cab, they just built a flat cover that goes up at a 12 degree angle to the top of the 4rth tail light so kind of a reverse angled tonneau cover?


So the tonneau cover folds onto it self with three equal pieces. and a small strap to keep it unfolding while driving/ for storage.

heres the link: I can always remove the soft material and lay down plastic, or aluminum or something more solid etc.

http://www.autoanything.com/tonneau-...-tonneau-cover


Im not gonna lie I'll have to research the perforated base plates and spoiler thing for the truck. I am still really new and have some reading to do but would it be a fair assumption for the following?

Truck got 19.5 on highway stock, after level kit and 2in taller, 1 in wider tires down to best of 17.7.

first mod: Adjusting driving style-I already drive the speed limit +/-2mph and CA drivers hate it lol. Im OCD with maintencs for fluids, filters, tire pressures, etc..

second mod-
part A- Full tonneau cover-only expecting it to really help on long trips for 1mpg boost to be honest?

part B-Angled Tonneau-copying the orange diesel truck-1-2mpg up at best for highway speeds?

Part C partial tonneau cover- I'll start with 50% of read portion covered, then move to a rear wing on a DIY cab level headache rack? something sturdy to fill the gap.

third mod - Air dam- Big Dave and others discovered it doesn't have to go to the ground as much as it needs to cover the tires. he got .75mpg boost at best but I have the material so only my time is needed.


Do you have some links to the perforated base plate and spoiler? Im curious since I haven't seen it come up on my research for improving economy with a pickup etc.

Again sorry, im new to this and I kind of settled for what I could do practically and without going to crazy on the truck etc.

I was mapping the outer limits of possibility, I don't know that these concepts have been applied to pickup trucks.

researchgate.net:The Effect of Base Bleed and Rear Cavities on the Drag of an SUV

See also Morelli, et al.

I don't think anyone has taken my suggestion for a truck wheel spat:

http://ecomodder.com/forum/member-fr...42-mudflap.jpg

No biggy. Always appreciate someone’s experience to help me out. The tonneau cover arrives Friday and I’ll drive a few tanks without to get something to base post cover economy off of.

I’ve been driving a lot of city mies and that drops me into the 14s pretty much always.

Somebody getting 40mpg or more might sneer at 0.76mpg improvement (generally nobody on this site, of course - we regard a win as a win no matter how small), or just disregard it as a small enough improvement that it might just be within the margin of error. But when your baseline results are in the teens, it's pretty big.

Visit the solar roadways!

Im basing my improvement assumptions off of Big Dave mostly to be honest.

He saw 3/4 of gallon mpg improvement with airdam, possibly .5mpg improvement with mirror delete/folding. I don't know if you seen the 2008-2010 mirrors on super duties they are HUGE! when I wired them in it helped immensely with visibility though lol....

So If I could squeeze a solid 1mpg off of air dam and folding mirrors in (maybe adding angled deflector) then 1mpg from tonneau cover, possibly 2 off an angled cover that would bring my 17.7 current best to a whopping 20.7 lol....

for me though diesel is $3.29-2.59 on average a gallon with my 13-isk k commute.

17.7mpg=2423.73 annual fuel cost

20.7=2072.4 annual fuel cost

Those are very simple calculations but I could save more as the diesel tax is going to increase three more times until 2020 lol. I have plans to move back to Idaho within a few years but for now this gives me something else to work on.

p.s. Anyone experience with turbo modifications on a powerstroke not for power but for fuel economy? My current GTP38 is stock but I bought what is called the wicked wheel 2 compressor wheel. I tow a lot and I get what called turbo shudder and it can cause damage overtime. A few companies came out with a new wheel, different fins, aluminum and it equates to:

5-6more psi boost, smoother/quicker response, and a little less egt's esp when I delete my EBPV valve on the turbo and add the high flow outlet. It causes very bad mpg in the winter for me :(

Awesome, sent him a pm. Tonneau cover should be here today and im going to stop by the body shop. ALSO.... I have some very heavy duty running boards that I feel would make excellent wheel skirt mounts. These arnt the normal two bracket/tube type. they completely cover the gap between the bottom of cab, 4 angled mounts with lights and for reasons I wont mention out of respect for someone over 350lbs... I know they hold up very well.

I don't feel I'll look into a skirt yet but I feel my trucks running boards would make a perfect mounting place if I ever got that interested. The offroad/hunting use of my truck is already making me work on some sort or semi quick mount system for an airdam etc...

I'm thinking of a mandible (jaw) that hinges at the top front of the wheel wells and in the raised (off-road) position uncovers a winch.

I like the idea. Im hoping to get my truck back tomorrow if not early next week. Then I can put a few tanks of fuel through to get my new base line and then I'll have almost a 2000 mile road trip to test the tonneau cover.

the test isn't perfect but I stop at the same gas stations there/back because im OCD and the military gave me some good landnav experience so I know about my max range, and the dead zones (those signs stating 100+miles no gas station) lol.

I'll be going from little north of bay area in CA to about 30 minutes south of the Canadian boarder in northern Idaho.

Thank you all for your input as well. When I take a new hobby I ted to go all in and I have to scale back when life reminds me I have an actual job ;)

I've been off this board for too long.

I had a 23 degree aerocap and while it may not have been optimum, it was damn effective. +3MPG over and open bed. Completely impractical: Limited bed storage and I couldn't see jack through it. But I gave it 3 years' try and it did work.

I replaced it with a hard tonneau. Not as effective for MPG +1-1.5 MPG over an open bed. But I had good visibility and easy access to the bed. Bad news: A strong wind got under it and I wound up chasing it through a muddy cornfield. C-clamps are not enough. Bolt it down to your bed or you will eventuall have to chase it.

What I'm thinking now is a hybrid. Put a ril wedge under the tonneau to raise it up to about a third the way up the rear window. No magic angle, just the height that doesn't impede my rear view. Obviously some sort of closure on the front to keep rain out. (I like dry cargo) this ought to give you about a 8 degree slope.

Follow up with something like Bondo's Drag Shield. That should give you aerodynamic performance closely approximating a optimized aeroshell but retain visibility.

I now have an ace body man to go to, so I'm not a bit squeamish about drilling or welding to my bodywork. Keep in mind, automobiles are built with mechanical fasteners and welding for a reason. Never underestimate the power of the wind to rip up sheet goods.

BTW, my air dam is entering its tenth year of service and shows no damage. It still looks weird and still works like a champ. The material - 3/8" ripstop conveyor belt is expensive, a real bearcat to fabricate, and nearly indestructible.

My next frontier: Mooneyes and rear fender skirts.

thanks for stopping by, seeing pictures of the big air dam on truck got me to do some googleing until I found you had been all over the place lol. I even found an old truck trend article where they showed some inner workings to your aeroshel and stuff.

So far I've narrowed it down to this: (mostly because of how often I use my truck)

1. flat full bed foldable tonneau cover for now: I have 2k miles of testing coming up. should be here today actually. plus the wife already bought it for me lol...

2. After Christmas: I'll fab a frame and either soft/hard top that I can raise to mid level of the cab if need for an angled tonneau cover. it seems a good mix of increase economy, usability, and work etc...

3. air dam. A buddy has access to belt (He told me his brother makes them for a living lol).

*did you have to do any crazy fab work to get the belt to hold onto your bumper? I've had mine off and its flimsy at best. I would thinking large washers and maybe welding a couple small pieces of angle iron to give the washer/bolts something to hang and cling too on the inside etc.


forgive my paint drawings. I learn/explain best visually lol.

Big Dave will know more, but I'd expect the problem to be drilling holes in the material.

You might do better using a tubular punch.

If you know somebody that makes conveyor belt for a living, he will have a 15 ton press and some round dies. Much, much easier than drilling and looks nicer, too.

I didn't do any fancy fab. Made a template. Drilled the bumper and welded nuts on the back. Use SS fender washers and capscrews, and tighten then down death for tight.

My dam clears grade by seven inches in front of tires and ten inches above grade between the suspension. Less and she drags - particularly when braking.

The success of the 1/2 tanto has led to the fat tail gate and duck but shape at the top of the gate. I noticed this after building myAero Tonto . And more recently seen explanations of what the aero designers were thinking, wind tunnel smoke show of the effect done by ford. The fat gate gave the air a place to reattach brief but enough to shrink the size of the hole in the back of the donut .you tube ford pick up . They widened and extended the 3rd brake light with a slight down angle to aim the air at this small patch of flat real estate. This is making it more difficult for toper/ tonneau cover manufacturers as the pice is no longer square ( curved doors are harder)and the flat space swings in a compound arc.

The pouch at the top of the gate is to turn the up draft(upper circulation bubble) to the rear sooner . Reducing the rooster tail effects protrusion above the tail gate. On my build the rooster tail is 100' behind the truck , with the exception of 2 strips from the tires. Then it fans out . An oddity is that the dust stays close to the ground(5-10') even at speeds of 70mph on dirt.
Apon closer inspection you'll notice that the back of the tonto extends 8" past the tail gate. Without interfering with tailgate use.
I was looking at garage door bottom seal as a flexable cab gap seal , but need some of that clear protective stuff the dealers install to prevent rust. Thies rubber seals slide into a bendable Al track. This was one of the findings, seal the cab to bed gap. The top edge is more important than the sides. Ford is using a labyrinth seal on the bed sides to alow movement without contact. This was also my finding at Darco tapeing my gap and cap gaps ( shrink wrap is under enough tension to Taco The Birdcage frame, as there is bias in the X Vs Y shrenk rate of this particular product that i didn't account for) -.037 Cd
The cap was good for -0.101Cd by it self. Air dam 5.5"in front of the tires and 3.5 in the center , was +0.017 ( bad). According to Darco + 12lbs of rear lift is generated @200mph with the cap. I had an incadent were I didn't latch the cap and drove miles till I finaly saw a car behind me in the center mirror.thinking to my self bright lights havent bothered me sence I put on the cap. "THE CAP. THE CAP IT IS OPEN " floting 10" off the tailgate. This was V1 25lbs this is how much air is travling up the back of the tail gate.

Boost at low Rpm aka cruse freeway.
For low rpm boost you need a small exhaust houaing or over fueling you can guess witch one we vote for. Small turbo. When in direct drive on the freeway /towing this will increase EGT and over speed /boost the turbo. So in order to get the best of both worlds the manufacturers have gone to VGT turbines Ive seen theas set up with a spring gate , just put a stop to prevent the spring from closing to far. The other alternative is aDiverter valve. This works by diverting all exhaust through 1 passage increcing the velocity of the exhaust stream giving it more Force against the wheel. This happens till the preset of 20psi(adjustable) were it opens both to sides progressively . Eg an hx 40 16cm becomds a n hx 40 8cm under 20psi. Im' thinking of using a With an additional adapter plate or T4 manifold this can be used on a T3 housing . Were as on a ford Im not fimilur with the up pipe set up, its doable.
Glad you are taking time to test a V1 V2 V2.1 if you can live with mirrors only as I do run the tonneau cover to just below the top of the cab. Slide it rear word( distance depends on your tail gate clearance and preference) add a sizeable gap filler to soffen the suddeness of the flat roof to 12° down. Your idea will work how well depends how far you are willing/can go.
An alternative to the 1/3 + wing is 1/3 + Bonneville spoiler -gurny flap. At both the cab and tail gate.

Look forward to reading about the drive.

Yuba City to Sandpoint is about 850-miles which lends itself nicely to an overnight trip.

May I remind the OP that retaining a high average mph relative to the travel set speed will have to do with the choice of stops during the day? Gains can be lost in bad choices. But, how to choose? It’s not quite simple, not if one wants an efficient travel plan. So, how does one define such?

It’s not a matter of fewer stops, per se, but making the necessary ones based on avoiding fatigue (which is safety), and in not losing the MPG margin increases of steady-state driving. A break every two hours of 10-15” is called for, and an hours meal plus fuel at about the days mid-point, or four hours.

Attention to details is the thing. I’m not going to go over the whole route, but a cursory examination shows that Yuba City, CA to Portland, OR though easily 50-miles farther is the same travel time as to Maupin, OR. Terrain is the problem for the shorter route, but traffic volume for the other. I’m going to use IH-5 as an example.

Metro areas are the bugaboo of trip planning. MPG will always be best on an Interstate. And that includes metro areas, unfortunately.

My trip planning for the big truck I drive always involves these sorts of trade-offs: in general, I choose the route that will give higher mpg even if “out of route” per company directions. The trick is in knowing where the OOR doesn’t consume much more fuel (time matters more to what I do) that company dispatch wants to know what I’m doing. I have to explain that it’s the same time at higher fuel mileage or both are better (which is less wear & tear on driver plus truck).

This is the big decision. Time versus distance. As what follows is choosing (so far as possible) the time to get through that metro area. Which itself is a matter of not screwing up my HOS (hours of service) in a significant way; I don’t want this choice to have an effect several days hence.

If I am confronted by the same time on the Interstate to go a greater distance than the US or State Highway, then I know the latter two will involve other than steady-state. It’ll be work. Bad sight lines, too. And unless other truck drivers recommend it (I can have a CB conversation), the longer but easier route will be a better choice. In the big truck.

To get through a metro area and not kill my patiently-added tenths of a MPG is a set of considerations. “Best” time is always just after morning rush hour. Until about 1100. After that, and till 2100 that evening, traffic builds and stays high.

1100 is about when I’d prefer to be at the other end of the metro area. That’s 75-miles from city center in most cases. IH-5 looks as though it’s a string city and built-up quite a few miles to the south.

So, now, to back farther into it, as an early stop to the day is congruent with an early start (daylight driving; no driving after dark), I need a stopping point for the first day of travel that gets me close enough to Portland that I’m at the other end of the metro area as above.

Do you see how this dictates my first day from Yuba City?

We want to just glide along thru the metro areas. Its not about the set speed, or almost not the average. It’s avoidance of braking & accel events to the greatest extent possible.

So now we’re at preservation of average speed through a metro area.

In my Dodge I run 59-mph at 1,725-rpm as my highest fuel economy cruise control set speed on an open highway. Assuming I’m solo (travel trailer at home) this offsets the assertive cruise control on gently rolling terrain (it’s the same mpg as running 62-mph, but cancelling cruise on the rises; I’ve zero interest in non-replicable stunt driving for economy). I might not pass anyone for several days while at this speed. I’m also not having to slow if at all for metro traffic, and I’m sure not accelerating away at their end. Or in and out of a fair number of construction zones.

When we take economy out of the picture and focus strictly on safety (statistically valid practices), the control to speed comes down to traffic volume, thence to vehicle spacing.

Lack of space means an accident sooner or later. Braking to achieve that is contraindicated. And, higher traffic volume means greater spacing problems, even when we distinguish between metro and rural. Town & Country.

Without going off-topic any farther (even as safe driving practice and best mpg track each other) lets posit that a speed below governed trucks — and barely above the 60-mph aerodynamic wall — is about 62-mph. Thus a range of 58-62/mph will cover the problems of spacing in all situations of relative volume and without obstructions.

While 5-mph under the posted limit is for amateurs (one has the sensation of being a rock that water flows around in a stream; ideal), it’s not ideal for MPG, which, again, is about steady state. No deviation in throttle-opening, no use of brakes and dead-minimal use of steering.

We all know that Frank Lees relatives like to run up on each other’s bumpers as metro traffic condenses near city center. And that they jam up again on the other side in accelerating away. So, how to avoid the worst of this even though we’re at a lower speed?

It’s in knowing what lane of travel.

At Portland we’re changing from one Interstate to another. How far out from that exit can we be in the correct lane? (As I don’t know, I’ve had in other cases had to decide on a general rule). Lane One (inside) is nearly always reserved for car traffic (no such thing as fast lane in a metro area to call it a rule), so we can’t use that. And Lane Two is the big truck version of “fast”, so we don’t want that either. Thus, unless Lane Three is the lane to enter and exit, choose it. Till about one mile or greater from the exit. Two miles is better. (If you’ve wanted a manual transmission, this is where it comes into its own: choosing a crawl speed as Frank & Co jam up).

Once last that exit, we are now looking for the point five or more miles past the return to the rural speed limit to come back up to speed and relax. But, why, one asks? Because it will take at least that long for the commercial traffic to sort itself out. True, at 59-mph it may not matter at all (seemingly). But as I’ve above indicated, it’s spacing that matters. Too many chances being taken by too many vehicles at this point.

Spacing: Not less than 100’. That means brakes applied. 200’ is the real minimum and the other vehicle is accelerating away even then. 500-700’ is what’s wanted. A quarter-mile is where one can relax.

.

Let’s go to rural driving as Part Two:

I’ve stated I like 59-mph. That it’s an appreciable drop in mpg when just over 60-mph. Greater than the gain in dropping speed. And, that 58-62/mph covers the range of economy that is outside that of governed trucks. Highest average mpg will be without accel/decel events & steering changes. It also tracks the least discrepancy between set speed and average mph.

No matter what is the set speed, the real story is that discrepancy when it comes to best vehicle operation. Longevity, safety, reliability, available power, fuel economy. . they all track together.

The roads have a design speed. That’s first limit. And we’ve worked backwards on high traffic volume in a metro area to preserve average mph. Now, let’s look at those factors mentioned just above, their maintenance:

55-mph as the National limit not so long ago was to enable vehicles to get into top gear plus a few rpm, and to offset both rolling resistance and aerodynamic resistance at a reasonable speed. From hereon, take it for granted that the gap between average and set grows. For a given road with given difficulties, AND the pressure of traffic volume.

So I’ll boil this part down to the essential: traffic management.

When one is slower than other traffic it becomes a matter of getting them to flow around one in a timely manner. And, as today’s traffic is overwhelmingly selfish (and increasingly stupid), it comes down to how one positions ones self in ones lane. To influence a beneficial outcome.

My mirrors predict my future. What is past is soon to be present. When you’re as old as Freebeard (and me) theres more to my past than to my future. Same here.

Traffic ahead is disappearing ahead. Not many worries there. So how to get the cretins around me (as they continually demonstrate their inability). We’ve mentioned volume and spacing. It’s applicability here is simple:

Surrounded by other vehicles, ahead, behind and beside, I have severely screwed up as a driver.

As a man, in short, as it’s his duty. For this to not ever happen is the entire point of managing traffic. And to minimize the effect on my precious tenths, is our delicate edge. But only when we can pull it off. Safely.

It’s a given that the cretins will engage in all sorts of unsafe behavior to get around a slow vehicle. But I’m not blindly rolling along. I’m timing actions I’m going to take as they come up.

First, I maintain lane center. That lane is mine to use as I see fit. (Consider the shoulder as invisible). And, from long experience, I can tell you that the cretins don’t have a good awareness of the lane stripe. What they have is a basic “distance” between their vehicle and yours they’re relying upon. (They also don’t know where is the starboard side of their vehicle. It’s abstract, not visceral). We’re going to use that against them. Not every time and not in every similar situation. But enough to keep the flow rate constant.


When ol’ gumby79 on his cell phone is coming into the 100-200’ foot overtaking to passing range (this determination is his comparative rate of speed) I’ll want to move to the left of my lane to “force” him to the left of his. It’ll work. Before he’s next to me I’m back over to center or a hair farther.

When it’s me in the Kenworth coming around, you’ll want to “act” a little more stupid.

You’ve been observing these drivers, correct? Seen who may need a little tune-up?

Big truck drivers are (should be) very aware of their starboard blindness. They “tend” to overcompensate. Move a little farther than they should. So if I’m coming up on a drunk home-boy, sawing the wheel, singing Norteno, I’ll move pretty far to the left of the passing lane.

This keeps those passing honest. Should see the reaction of some truck drivers look down and over to me that I’m more sober than them. A lot more serious.


Next is a crowd looking to get around. Or a big truck with not much headway (low comparative rate). This is the more common problem. When it’s me in any vehicle I’ll be on the CB to the big truck and tell him when he moves left, I’ll cancel cruise and somewhat rapidly decelerate. That’ll get him around me quite quickly. And not allow others to jam up behind him. (If they jam up behind me, I just laugh at their dumb butts).

The goal is always spacing. Beside me, or in front of me. And even behind me.

Seeing what’s ahead of me tempers all of this. May not be worth the trouble on a crowded Interstate. On those days I’m cancelling cruise and backing off fairly often to keep spacing. And on those days my decel events add up and it becomes a chore on how to accelerate back to set speed. (Experience makes the difference. So practice).

Part Three:

Now we’re back at the beginning.

I already know how to have done the above. My income depends on it. Don’t ever assume you can walk into a man’s place of work and proceed to tell him how to better do the job. Non-professional drivers fool themselves all the time with this. They’ve been holding the steering wheel and jamming the go pedal for X years, and hey, they know what they’re doing.

Ha!

It’s a really bad assumption. Know how often I see a guy doing a good job? Maybe every other month. About 20,000 miles or tens of thousands of cars to have to have observed.

So why do I bring it up? Because we all start from ignorance. Driving for economy is driving for safety in my view. Almost identical. Safety trumps economy, and they rarely collide. But economy wont ever happen at speeds much above sixty. That’s demonstrable. (It’s not just fuel).

For a given vehicle under given conditions.

Aero alone isn’t enough of a marginal change. The proof is in the annual average mpg. Not a trip or two. So, how to reconcile economy and the desire to “make good time”?

What is “good time”. For the 99% it’s obviously emotional. It’s a sensation, and nothing more. Can you grow out of that? Apply reason? There must be a test, right? Right! That test is:

Average MPH

Take it as a given that on trips of 300-miles or less there isn’t an appreciable difference between 62 and 68-mph. A calculator is no help. Tells us nothing. The only thing that does is

Engine Hours

From Point A to Point B is the length of the trip. From engine start to engine kill is the time (where the master clock is recording all minutes). Average MPH is the actual trip speed. Not my cruise control set speed.

Here’s an example: I left Ft Worth late one day at the usual 67-mph governed speed and by accident covered the same distance each day to journeys end. IH-20. Cities, traffic, construction. About 425-miles each day and within five minutes. Time mattered and nothing else. But my average mph for both days was 56-mph. I didn’t leave the engine idling for any reason. I wasn’t backed off. I wanted to be at delivery ASAP. I couldn’t have done it faster given constraints.

So, how could I have done it faster? Easy. Traffic volume. An earlier start to day, thus an earlier finish (I couldn’t as loading was a clock time constraint). But if I could have, what would have been the difference?

As theese ees mi yob, I’ve had plenty of occasion to test: as much as five mph to this average. A quite high one for a 79,000-lb big truck. Only happens under certain conditions.

One condition as mentioned is always the safety of not driving at night. Not always possible with a big truck.

But for a civilian it amounts to an early daily departure and an early arrival. Gets the most available from that margin. Test it!!

And with it plan every stop in advance. ON the road, not three blocks away. EVERY two hours a 10-15” break. AT the midday point, an hour fir a meal after re-fueling. Etc.

Do some research. I really don’t care how many times one has covered a route. I looked up fuel stops past Portland on the way to Spokane and had to bypass both the Pilot and Loves truckstops in favor of an independent just a little farther east based on nothing more than reviews on Truckers Path. Not just big truck problems, but delays for diesel pickups as well. (The Western Express at Hermiston, OR was the choice).

The exception to

1) Leave early (time the metros)
2) Drive 58-62 steadily on cruise
3) Choose efficient stops

Is,

4) Meals

Make the old lady (and yourself) happy by picking a place to eat at www.roadfood.com (or similar) even if it involves OOR. Otherwise, what’s the point of taking ones own vehicle?

Maybe she’d rather pack y’all a nice lunch. Got it. But if there’s a place that intrigues you, go try it out one day. Not years from now.

A man with control over average mph — with trade offs understood — will make time more easily than the guy who passes him three times in one day. Without the wear and tear. Preserving the vehicle he owns. Not burning more fuel than is necessary. And not get there any later.

1). Run this trip at 68. Leave late. Make no stop plans. Both directions.

2). Another time run it another at 62. Plan it. Leave and stop early.

There won’t be an appreciable difference on that 1,700-mile round-trip.

Or, you run it as in One, and I’ll run it as in Two. You do up the aero. Remove it before my trip. Think you’ll beat me in mpg? You know you won’t, even though I’ve never been dumb enough to own a Ford pickup, AND, I don’t know the PNW for squat. Three part handicap before managing overtaking traffic.

So it’ll come down to how much faster were you?

Get “average mph” and the rest falls into place on how to plan. The industry standard is a 50-mph average for all miles & total time. That includes breaks. The online mapping services show an average. Only engine time. So, must include stop time. (And compromising safety by tempting fatigue thus avoiding a rest stop is verboten).


Best of luck. As the drivers say, Be careful.


.

You might want to read some of us lazy Dodge drivers. Don’t have to work nearly so hard.

DieselDave (50+ mpg)

skyking (two different trucks)

Hersbird (don’t know where he is on his recent CTD acquisition).

(“My” thread is something or other about Town & Country MPG in a CTD).

.

Always a fun read. Unfortunately I can’t say I’m a Supreme hyper miler yet, but I did OTR trucking and flatbed trucking for a bit after I got out of the Air Force in 2014. I’m familiar with the more common smart driving techniques and to be honest this is how I usually drive on the way to Idaho/back:

Map out my fuel stations for a combination of time/miles/ practicality of route/
I usually fuel up 3/4 times. There are some very steep and long grades to and from my route. It’s a 14.5hour drive if you never had to stop but if I leave at 4:30am I usually get to Sandpoint (about 20 minutes last at least) by 8:30-9pm.

My usual speed is 65-67 mostly to keep tailgaters off my butt but I’ve gotten over them to be honest. I used to speed out of politeness but now the tailgaters can suck it and I drive just fine.

I don’t like packs, gobbles, groups, of vehicles so I stay far behind and I usually find away around major traffic areas through an app called Waze. It’s been a lifesaver compared to having your wife look through a rod atlas lol.

I’m by no means as strategic as you guys yet, but I’m definitely more conservative and defensive of a driver than arguably 90% of the other drivers. Esp in CA... I’ve been in CA since 2008 and wow! It’s by far wosrse here than any other state I’ve been to. So many people texting, tableting, tailgating and the like it’s no wonder Insurance rates are so high.

But I degres, I really enjoy the help and advice and tools I’ve gotten here and I’m really excited to make a 7640 lb 4x4 diesel get into the 20s to start and then maybe more if I catch the hypermile bug lol.

angle
 

From Hucho's text,the optimum angle will be a function of the length of the downward-sloping ramp,as a percentage of the overall body length.
We used to have that graphic,but PhotoBucket made it go away.:(
If you have that number,I'll get you an angle.

Wheel base is: 141.8inches

Total length is: 227 inches/ 18.91ft

Ooops!
 

I screwed up!
In my mind,I had the cover descending from the top of the cab down,like a partial aero shell,which is not what you want.Sorry for the confusion on my part.
:o

No problem. No construction on an angled tonneau cover until January anyways. I have some ideas though and I’ll start buying supplies soon. I’m keeping it simple and waterproof hahaha. Hopefully uv resistant too. The Sun eats rubber things here in CA.

There’s a running joke with tuck tires,

If you don’t wear them out in a few years The Sun will, so drive, drive lol

Do the diging , to find the rpm sweet spot. This will change based on truck configurations. Eg 58-62 for slowmover with a 3.55 ×.75 Od 2.6625 final Vs my 62 -70 3.55× .69OD 2.4495 final. Your rubber gear (larger/smaller tires) changes will move the sweet spot as well.
Rout segregation
Leave I5 at weed on97 this is better terrain fewer shallower grade / passes. Both UP and BNSF Railroads have abandoned the I5 cordor from weed,Ca to Eugene ,Or the Siskiyou mountains infavor of the Cascade range(extra100mi). For a savings of 500ga per train , and 2000Tons higher tow limit(4200T Vs6400T). I 5 WAS SLATED TO RUN WERE 97 IS. But cost to get between the east side of Klamath lake, the RR and shifty volcanic mountain was too high. And the west side (Westside Road from hwy 140 to Chiloquin /fort Klamath) is a snw belt.