Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

slowmover · 09-17-2010, 12:27 AM

slowmover:
You seem to think that safety is more important the FE, I agree. But lets keep on topic of helping Braebyrn get beter FE out of his setup.

He wants to reduce his costs, which is my point throughout the above post. But safety trumps FE in all events. Have you not read of Aeroheads trailer that failed due to a loose lug nut? Destruction trumps pocket money changes. With respect I doubt you've ever run 4000 miles in a month, much less a long week. I have, many times. What it takes out of a man reduces his alertness, and a poorly-equipped rig is flat dangerous. Cops and firemen have it easy -- real easy -- because being a truck driver is nearly the most dangerous occupation in America. There are old truck drivers and there are bold truck drivers, but there are no old & bold truck drivers.

How this man drives is more important, for FE, than band aids. A well-sorted rig is "tight" and takes less energy to go down the road. The average MPG will rise appreciably once details are attended AND driving style modified to suit load, road, traffic and weather.

I'm guessing he waves at the road where his house sits, is wearing out his truck prematurely, and isn't making what he thought (normal enough for guys like us dumb enough to do this job), and that he hopes to control his fuel costs with some aero. Well, trip-planning is the key to that, and cost control comes from being able to predict the margin ahead of time, which takes numbers. And a loose, sloppy rig with a new-guy driver flat-footing it everywhere is the classic went out on the road and went home broke at the end of a year. Yeah, I know what I'm talking about, and there are good good reasons to put things in the right order.

I use a infrared temperature tool to check the tires for the correct load. It has been my way of leveling the load. But it requires me to drive for about 10 minutes to heat up the tires. Not the best way to do it for sure.

Takes 1.5 hours of steady state driving for tires to stabilize in terms of temperature. Plus, while external readings are handy, they in no way tell us what is happening INSIDE the tire which is more important. A TPMS is a good idea (again, more so than aero band-aids). You want a SHERLINE scale, as well. Plus, a run across a CAT Scale when things change (more than a few hundred, but well short of a thousand). Tighten lug nuts on both vehicles (keep a dedicated torque wrench) before every morning departures AFTER you read and record pressures.

You want to run tire pressures according to load, both vehicles. Get a quality pressure gauge (A dual-type -- does two at once -- is on my list. You can get gauges that can be calibrated).

What can I do different for the hitching for the sway from passing cars or cars passing? I have the load leveler bars, but do not use the sway bar.

Your hitch rigging, is -- to put it politely -- a joke. And that goes for anyone who doesn't certify the numbers on a weight scale (use CAT Scales; tickets are deductible). This goes for 95% of rigs out there. While there's a bonus in fuel economy, there's a direct relation to tire/brake life (and steering/suspension life), and the biggest money saver is that you'll live through the worst imaginable incidents by having better rig braking/handling. The trailer will not so easily upset the tow vehicle. Tail wags the dog. And a friction style anti-sway needs to be disconnected in rain (when you need it most).

But when I added the last boattail, it amplified the sway caused by passing vehicles.

I'm not surprised. Without NUMBERS DERIVED FROM SCALE READINGS there are nothing but the wrong kind of surprises lurking. The boat-tail may have done nothing more than free up the wrong kind of energy.

An aero rig is not more stable, per se. In general ways it is. But "the rig" (both vehicles, coupled, as definition) must meet manufacturer guidelines for proper hitching. Once you've hitched up you have ONE vehicle (is the way to look at it). A WDH applies leverage to reduce the TW to return the steer axle to original ride height and weight, and two, to "return" some of the TW to the trailer axles (which is why you want BEST tires on the trailer, and why you MUST weigh the rig empty, loaded, hitched and unhitched. And continue to do so over time to learn how to pressurize tires, tension the hitch, and adjust the cargo).

Start with the tow vehicle. Proper Load Range tires not more than 5-years in use? Shock absorbers like new? Brakes? No bad bushings or sloppy steering? Alignment Etc.

Then the trailer. What tires (and wheels)? Has it been weighed empty and loaded? What is the tongue weight? Does it represent 10-15% of trailer weight (all measurements made level) as 12-13% is probably best (and changes with every re-loading or delivery). What of side-to-side weight discrepancies? Is the cargo being secured according to DOT regulations with DOT certifiable securement devices? (It's your life, bubba, and if it ain't, it's a wheelchair . . or someone else ridin' one). GO GET THE TRAILER AXLE ALIGNMENT CHECKED. Add shock absorbers. Balance the wheels/tires (CENTRAMATIC). Check for brake drag and learn to adjust drums. Re-wire the brake electrical. Etc. Etc.

A square, non-aerodynamic trailer has some "built-in" antisway, since it takes such an enormous amount of comparable power to tow it resists side-to-side movement to a degree. An aero trailer does not, in comparison. (These are generalities, a manner of speaking). The latter trailer is not pushing a wall which resists other movements.

Once the rig is sorted -- and you have numbers to work from -- then the aero aids are worth trying. Don't put the cart before the horse, or let me hear that high school graduate in this day of the Internet can't find good information (There are LTL and hotshot forums out there that can be of help).

I'm all for increased FE, but do it in order. Get the hitch rigging squared away FIRST.

I don't know what kind of hitch you are using, but if it is the old friction bar type, then trash it, those are worse than useless. The best low cost WDH is a REESE Strait Line "Dual Cam". You can spend quite a lot of time on RV.Net and read up on how to use a WDH. (I have, and recommend HIGHLY a sway-eliminating hitch: [in reverse order of preference], a HENSLEY ARROW, a PRO PRIDE or a PULLRITE.)

You are looking to return the steering axle to original ride height and weight -- per a scale -- to have best handling/braking once hitched.

Tongue weight is NOT static: an 800# TW can be 8000# of force in the wrong situation on the big road (numbers are trailer dependent, etc)

First, you'll want scale readings of truck, empty: (driver/full fuel/normal junk)

And scale tickets to correspond to this:

(Ron Gratz over at rv.net)

Weighing #1 -- TT attached and Weight Distribution Activated

Let Front Axle Load be "FA1"

Let Rear Axle Load be "RA1"

Let TT Axles Load be "TT1"

Then, while in same position on scales, take
Weighing #2 -- TT attached and Weight Distribution Not Activated

Let Front Axle Load be "FA2"

Let Rear Axle Load be "RA2"

Let TT Axles Load be "TT2"

Then, drive off scales and drop TT. Return to scales and take
Weighing #3 -- TV only -- TT Not Attached

Let Front Axle Load be "FA3"

Let Rear Axle Load be "RA3"

From the above values, you can calculate:

TV weight = FA3 + RA3

Gross Combined Weight = (FA1 + RA1 + TT1)
- should also be equal to (FA2 + RA2 + TT2) if scale weights are correct

TT Weight = Gross Combined Weight - TV Weight

Tongue Weight = (FA2 + RA2) - (FA3 + RA3)

Load Transferred to TT Axles
when WD System in Activated = TT1 - TT2

HOW DOES A WDH WORK?
RV.Net Open Roads Forum: Towing: Weight Distribution (WD) Hitch --- How it Works

http://www.trailerlife.com/images/di...wGuide0801.pdf

FORMULA CALCULATOR
Travel Trailer Weight Calculator

(ignore "safety margin" shown; it is incorrect)

And the further posts may not be on the right track. That trailer is an FE disaster due to height (reduce that will help enormously), width (preferably under 8'), AND LACK OF ROLLED CORNERS AND EDGES! Wind just piles up any and everywhere on that thing. BUT, it's too tall (number one) and too wide (but not as badly).

Another number: When the rig is hitched, what is the distance between truck tailgate and trailer front wall? More than 30"? Then don't try to "connect" the two. Treat each vehicle separately. The worse you make your truck -- solo -- the worse it will be for towing. (I won't say anything about it being GM. At least it ain't a Phord).

An aerolid would be good on the truck (or a low, close-fitting bed topper, not a two-story one; or a tonneau), and for the trailer probably a nose-cone plus (in order to experiment) some different tail configurations.
BUT

you must meet state and federal laws about overhang, proper license display and lighting. (You sure don't want DOT giving you the gimpy eye with some weirdo lookin' trailer depending on your license classification, logbooks, etc, etc).

Your biggest gains for reduced fuel use will be in trip planning. One of those forums above would probably help. If you don't understand that 10-hrs at 60 mph is better than 8.5 hours at 70 mph you may not get ahead in controlling your costs. Don't drive into the night, but leave earlier. Plan ALL stops ahead of time (mile marker such and such) and know the time and distance between each. Stop every two hours (not 2.5 hours). Stop every 4-hours to eat, fuel, whatever . . for 45" to 60". Learn stretching and some aerobics. Etc. Have alternates.

So, how ever much you are willing to do, here is the big question: What is your fuel cost expressed in cents-per-mile? (And, what is your overall cpm NOT covered by the IRS? If you increase your mpg, what will be the percentage gain on your non-covered portion of expenses?)

And, if you (like me) continue to be dumb enough to like this job, what will your next enclosed trailer look like? 8x8x20? Or 6x6x30? Wood or aluminum framing? Beam or independent suspension? Drum or disc brakes? Both sizes hold about the same, but, . . . .

Best.

(PM me with your email if you want my too-long, and unorganized collection of notes and links per towing and better mpg in a .pdf).

09-17-2010, 12:27 AM	#20 (permalink)
slowmover Banned Join Date: Oct 2009 Location: Fort Worth, Texas Posts: 2,442 2004 CTD - '04 DODGE RAM 2500 SLT Team Cummins 90 day: 19.36 mpg (US) Thanks: 1,422 Thanked 737 Times in 557 Posts	slowmover: You seem to think that safety is more important the FE, I agree. But lets keep on topic of helping Braebyrn get beter FE out of his setup. He wants to reduce his costs, which is my point throughout the above post. But safety trumps FE in all events. Have you not read of Aeroheads trailer that failed due to a loose lug nut? Destruction trumps pocket money changes. With respect I doubt you've ever run 4000 miles in a month, much less a long week. I have, many times. What it takes out of a man reduces his alertness, and a poorly-equipped rig is flat dangerous. Cops and firemen have it easy -- real easy -- because being a truck driver is nearly the most dangerous occupation in America. There are old truck drivers and there are bold truck drivers, but there are no old & bold truck drivers. How this man drives is more important, for FE, than band aids. A well-sorted rig is "tight" and takes less energy to go down the road. The average MPG will rise appreciably once details are attended AND driving style modified to suit load, road, traffic and weather. I'm guessing he waves at the road where his house sits, is wearing out his truck prematurely, and isn't making what he thought (normal enough for guys like us dumb enough to do this job), and that he hopes to control his fuel costs with some aero. Well, trip-planning is the key to that, and cost control comes from being able to predict the margin ahead of time, which takes numbers. And a loose, sloppy rig with a new-guy driver flat-footing it everywhere is the classic went out on the road and went home broke at the end of a year. Yeah, I know what I'm talking about, and there are good good reasons to put things in the right order. I use a infrared temperature tool to check the tires for the correct load. It has been my way of leveling the load. But it requires me to drive for about 10 minutes to heat up the tires. Not the best way to do it for sure. Takes 1.5 hours of steady state driving for tires to stabilize in terms of temperature. Plus, while external readings are handy, they in no way tell us what is happening INSIDE the tire which is more important. A TPMS is a good idea (again, more so than aero band-aids). You want a SHERLINE scale, as well. Plus, a run across a CAT Scale when things change (more than a few hundred, but well short of a thousand). Tighten lug nuts on both vehicles (keep a dedicated torque wrench) before every morning departures AFTER you read and record pressures. You want to run tire pressures according to load, both vehicles. Get a quality pressure gauge (A dual-type -- does two at once -- is on my list. You can get gauges that can be calibrated). What can I do different for the hitching for the sway from passing cars or cars passing? I have the load leveler bars, but do not use the sway bar. Your hitch rigging, is -- to put it politely -- a joke. And that goes for anyone who doesn't certify the numbers on a weight scale (use CAT Scales; tickets are deductible). This goes for 95% of rigs out there. While there's a bonus in fuel economy, there's a direct relation to tire/brake life (and steering/suspension life), and the biggest money saver is that you'll live through the worst imaginable incidents by having better rig braking/handling. The trailer will not so easily upset the tow vehicle. Tail wags the dog. And a friction style anti-sway needs to be disconnected in rain (when you need it most). But when I added the last boattail, it amplified the sway caused by passing vehicles. I'm not surprised. Without NUMBERS DERIVED FROM SCALE READINGS there are nothing but the wrong kind of surprises lurking. The boat-tail may have done nothing more than free up the wrong kind of energy. An aero rig is not more stable, per se. In general ways it is. But "the rig" (both vehicles, coupled, as definition) must meet manufacturer guidelines for proper hitching. Once you've hitched up you have ONE vehicle (is the way to look at it). A WDH applies leverage to reduce the TW to return the steer axle to original ride height and weight, and two, to "return" some of the TW to the trailer axles (which is why you want BEST tires on the trailer, and why you MUST weigh the rig empty, loaded, hitched and unhitched. And continue to do so over time to learn how to pressurize tires, tension the hitch, and adjust the cargo). Start with the tow vehicle. Proper Load Range tires not more than 5-years in use? Shock absorbers like new? Brakes? No bad bushings or sloppy steering? Alignment Etc. Then the trailer. What tires (and wheels)? Has it been weighed empty and loaded? What is the tongue weight? Does it represent 10-15% of trailer weight (all measurements made level) as 12-13% is probably best (and changes with every re-loading or delivery). What of side-to-side weight discrepancies? Is the cargo being secured according to DOT regulations with DOT certifiable securement devices? (It's your life, bubba, and if it ain't, it's a wheelchair . . or someone else ridin' one). GO GET THE TRAILER AXLE ALIGNMENT CHECKED. Add shock absorbers. Balance the wheels/tires (CENTRAMATIC). Check for brake drag and learn to adjust drums. Re-wire the brake electrical. Etc. Etc. A square, non-aerodynamic trailer has some "built-in" antisway, since it takes such an enormous amount of comparable power to tow it resists side-to-side movement to a degree. An aero trailer does not, in comparison. (These are generalities, a manner of speaking). The latter trailer is not pushing a wall which resists other movements. Once the rig is sorted -- and you have numbers to work from -- then the aero aids are worth trying. Don't put the cart before the horse, or let me hear that high school graduate in this day of the Internet can't find good information (There are LTL and hotshot forums out there that can be of help). I'm all for increased FE, but do it in order. Get the hitch rigging squared away FIRST. I don't know what kind of hitch you are using, but if it is the old friction bar type, then trash it, those are worse than useless. The best low cost WDH is a REESE Strait Line "Dual Cam". You can spend quite a lot of time on RV.Net and read up on how to use a WDH. (I have, and recommend HIGHLY a sway-eliminating hitch: [in reverse order of preference], a HENSLEY ARROW, a PRO PRIDE or a PULLRITE.) You are looking to return the steering axle to original ride height and weight -- per a scale -- to have best handling/braking once hitched. Tongue weight is NOT static: an 800# TW can be 8000# of force in the wrong situation on the big road (numbers are trailer dependent, etc) First, you'll want scale readings of truck, empty: (driver/full fuel/normal junk) And scale tickets to correspond to this: (Ron Gratz over at rv.net) Weighing #1 -- TT attached and Weight Distribution Activated Let Front Axle Load be "FA1" Let Rear Axle Load be "RA1" Let TT Axles Load be "TT1" Then, while in same position on scales, take Weighing #2 -- TT attached and Weight Distribution Not Activated Let Front Axle Load be "FA2" Let Rear Axle Load be "RA2" Let TT Axles Load be "TT2" Then, drive off scales and drop TT. Return to scales and take Weighing #3 -- TV only -- TT Not Attached Let Front Axle Load be "FA3" Let Rear Axle Load be "RA3" From the above values, you can calculate: TV weight = FA3 + RA3 Gross Combined Weight = (FA1 + RA1 + TT1) - should also be equal to (FA2 + RA2 + TT2) if scale weights are correct TT Weight = Gross Combined Weight - TV Weight Tongue Weight = (FA2 + RA2) - (FA3 + RA3) Load Transferred to TT Axles when WD System in Activated = TT1 - TT2 HOW DOES A WDH WORK? RV.Net Open Roads Forum: Towing: Weight Distribution (WD) Hitch --- How it Works http://www.trailerlife.com/images/di...wGuide0801.pdf FORMULA CALCULATOR Travel Trailer Weight Calculator (ignore "safety margin" shown; it is incorrect) And the further posts may not be on the right track. That trailer is an FE disaster due to height (reduce that will help enormously), width (preferably under 8'), AND LACK OF ROLLED CORNERS AND EDGES! Wind just piles up any and everywhere on that thing. BUT, it's too tall (number one) and too wide (but not as badly). Another number: When the rig is hitched, what is the distance between truck tailgate and trailer front wall? More than 30"? Then don't try to "connect" the two. Treat each vehicle separately. The worse you make your truck -- solo -- the worse it will be for towing. (I won't say anything about it being GM. At least it ain't a Phord). An aerolid would be good on the truck (or a low, close-fitting bed topper, not a two-story one; or a tonneau), and for the trailer probably a nose-cone plus (in order to experiment) some different tail configurations. BUT you must meet state and federal laws about overhang, proper license display and lighting. (You sure don't want DOT giving you the gimpy eye with some weirdo lookin' trailer depending on your license classification, logbooks, etc, etc). Your biggest gains for reduced fuel use will be in trip planning. One of those forums above would probably help. If you don't understand that 10-hrs at 60 mph is better than 8.5 hours at 70 mph you may not get ahead in controlling your costs. Don't drive into the night, but leave earlier. Plan ALL stops ahead of time (mile marker such and such) and know the time and distance between each. Stop every two hours (not 2.5 hours). Stop every 4-hours to eat, fuel, whatever . . for 45" to 60". Learn stretching and some aerobics. Etc. Have alternates. So, how ever much you are willing to do, here is the big question: What is your fuel cost expressed in cents-per-mile? (And, what is your overall cpm NOT covered by the IRS? If you increase your mpg, what will be the percentage gain on your non-covered portion of expenses?) And, if you (like me) continue to be dumb enough to like this job, what will your next enclosed trailer look like? 8x8x20? Or 6x6x30? Wood or aluminum framing? Beam or independent suspension? Drum or disc brakes? Both sizes hold about the same, but, . . . . Best. (PM me with your email if you want my too-long, and unorganized collection of notes and links per towing and better mpg in a .pdf). Last edited by slowmover; 09-17-2010 at 12:50 AM..