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Configure a HDT to Compare to a F350 Crewcab Long Box


Dollytrolley

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So…..Often on the forum we get some “Lurkers” that wants to compare “Super-Pickups” with a HDT however it sorta turns out that most HDT conversions are not well configured very close to any pickup wheelbases or overall length …..SO…...”What-IF” we were to configure a HDT the same as a Brand new F350 Crewcab Long Bed LGT? ? ?

Now out of the kindness of his heart Scrap has "Donated" FOUR brand NEW KWoppers to the thread so we can slice and dice ACTUAL trucks any way we desire........Thanks Scrap.

BASE TRUCK:

 Lets start with Scraps shortest truck (#3) and it is: 13L 6X2, 197" WB, 100 Gal fuel tank @118", Dry=14,808 Lbs, Steer=9,280 lbs , Drive=5,528 lbs C G=73.54"

Now we shorten the above wheel base 21” to arrive at the F350 wheelbase of 176” so our now our steer axle=8,259 /55.77% and drive axle = 6,549 /44.23% and C G= 77.84”

Lets A$$ume 13 speeds loading for the first cut so.....

Steer is Zero Datum,  

Driver & Pass = 86" sta

Sleeper cargo= 100" sta

Hitch pin = 194" sta  (18" aft of drive axle)

Back of cab=116” (52” Condo)

Back of cab to end of frame = 100”

Drive axle= 176"

End of Frame= 216” (Total length front bumper to end of frame 266” same as F350)

Loads are: Driver & Pass=340 lbs /// Fuel 600 lbs /// sleeper cargo= 100 lbs/// Hitch and trailer pin load = 8,000 lbs

Results Truck #3 loading F350 Compare 

Steer= 8,039 lbs  33.25%

Drive= 16,134 lbs  66.75%

C G= 117.47"

Total Wt= 24,173 lbs

Funny thing is that the bed behind the cab on the HDT is LONGER that the F350 and they are the exact same length overall AND the HDT will turn much sharper.......

 

Drive on..........(Same to ........same........sorta)

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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Hey Short,

Ya see what happens when a geezer has too little prune juice mixed with too much Crown Royal and too much Helium pumped into the drive axle tires.........good proof reading......

 

Drive on............(2 many thumbs.......2 type)

 

 

 

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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Or you could just do this:  

168" Wheelbase   260" Overall length.  Problem solved

592ee312d0832_TowingWPavatar.jpg.c41c7997b136721d83b1d8e64fc9eb1c.jpg

 

 

 

Jeff Beyer temporarily retired from Trailer Transit
2000 Freightliner Argosy Cabover
2008 Work and Play 34FK
Homebase NW Indiana, no longer full time

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For "most" HDT trucks with short sleepers and, set back axles.   The minimum wheelbase with a 60-66" cab axle distance is about 186"      I have played with a number of bed configurations, the average OAL I use is 276-282"     Any bed that extends past the rear axle will limit how close the trailer can be coupled to an RV 5th wheel.    

 

My own design briefs include removing the fuel tanks and, using a single large tank behind the rear axle for weight shift.    The quick numbers on that are 9000 front axle, 7000 back axle with full fuel 192" WB unladen.   That is with a 13L Cat and 13 speed.   

 

Steve 

2005 Peterbilt 387-112 Baby Cat 9 speed U-shift

1996/2016 remod Teton Royal Atlanta

1996 Kentucky 48 single drop stacker garage project

 catdiesellogo.jpg.e96e571c41096ef39b447f78b9c2027c.jpg Pulls like a train, sounds like a plane....faster than a Cheetah sniffin cocaine.   

 

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21 minutes ago, beyerjf said:

Or you could just do this:  

168" Wheelbase   260" Overall length.  Problem solved

592ee312d0832_TowingWPavatar.jpg.c41c7997b136721d83b1d8e64fc9eb1c.jpg

 

 

 

This is the route I would like to go.  I still need to get in an Argosy and go for a ride.  How do you think singling one would affect the overall driving characteristics?

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Singling a cab over shouldn't make any more difference in handling than singling a conventional, all depends on the numbers, which Dolly Trolley will be more than happy to help you with....

What is different and a matter of pure physics is the driver's position relative to the front axle, directly above instead of maybe 36" behind on a conventional. The handling "perception" is likely to be different. Just like the sensation some people get when they ride in my tractor and are absolutely convinced it is going to tip onto it's nose. Funny to watch. Never going to happen. 

Jeff Beyer temporarily retired from Trailer Transit
2000 Freightliner Argosy Cabover
2008 Work and Play 34FK
Homebase NW Indiana, no longer full time

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3 hours ago, beyerjf said:

Or you could just do this:  

168" Wheelbase   260" Overall length.  Problem solved

592ee312d0832_TowingWPavatar.jpg.c41c7997b136721d83b1d8e64fc9eb1c.jpg

 

 

 

 

2 hours ago, beyerjf said:

Singling a cab over shouldn't make any more difference in handling than singling a conventional, all depends on the numbers, which Dolly Trolley will be more than happy to help you with....

What is different and a matter of pure physics is the driver's position relative to the front axle, directly above instead of maybe 36" behind on a conventional. The handling "perception" is likely to be different. Just like the sensation some people get when they ride in my tractor and are absolutely convinced it is going to tip onto it's nose. Funny to watch. Never going to happen. 

Jeff, you bring a great set of points to the table with your comments.......

Back in the stone age when I was a wind-tunnel-bum a bunch of Argosy-geeks were hogging a lot of tunnel time with some pretty slinky tractor / trailer fairings in the hitch joint area.......

I had my own tunnel headaches with some Ugly aircraft so the truck geeks ignored me but I could not help but notice that the Argosy with a properly faired trailer spit out some VERY impressive LOW drag numbers in the tunnel......(Damn sight better numbers than my Ugly aircraft).

One of my best long time friends is THE best low-speed Aero-Geek on earth and he did TONS of wind tunnel testing on almost every heavy truck made and the Argosy was right up at the top of the heap with low drag numbers. 

The low drag heavy truck lost a lot of favor after Diesel prices peaked and then dropped.

The real problem with heavy truck low-drag concepts are that many trucks are hitched to a lot of different HIGH-DRAG trailers and the time, effort, and money it takes to properly fair in the trailer to tractor junction has very little appeal for most truck operators.

It would that HDT RV owners might have some interest in a Sleek-Low-Drag Tractor / Truck / Trailer combo........maybe?

One of the challenges of the Truck / Trailer combo is the Aero-Treatment of the trailer-aft-body....... the flat-back of our RV trailers is the WORST shape to have .........VERY HIGH DRAG......

As you walk down the concourse at the airport and you look UP and the HUGE nose of a B-747 most people would think that that fat noise would be High Drag to push through the air ......but they would be amazed how Low-Drag the 747 really is and in fact Vegas Flyer will tell you that the last 150 miles descending into the airport is typically a glide at idle power just because that big ole aircraft is a heck of a low drag glider........You see when you look at the side view of the 747 most peoples eye is drawn to the HUGE forebody and nose and few will notice the sleek and nicely faired tail section of the Long body of the 747 ............

A old time Aero-Rule is basically that the afterbody should be at LEAST three times as long as the widest section of the body so a 10 foot high body would taper 30 ft after the largest body section was attained aft............Not likely on a RV so other methods would be employed......more on these "methods" later........

 

Drive on...........(Dont let RVing be too much of a .....Drag)

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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3 hours ago, Chad Heiser said:

This is the route I would like to go.  I still need to get in an Argosy and go for a ride.  How do you think singling one would affect the overall driving characteristics?

Chad,

You have likely seen a LOT of singled very short  COE tractors but your eye is likely drawn to the 14 FOOT WIDE by 70 FOOT long mobile home with FIVE axles with TEN crappy Cheep tires tucked in tight behind the mobile home toateeeer.........

Now a Mobile Home Toater is not the nicest tractor in the road..... but they do an amazing job hauling the WORST trailers on the road and for the most part they get the job done without much notice.

When I was a puppy Grumps had a buddy  that had a fleet of MH Toaters and a few times I changed U joints as a slave-child because the driveline was so short that it hardly had room for the slip joint and the angles were crappy so the joints would wear a lot.......

 

Drive on...........(How short is......t00 short?)

 

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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You are right about the trailer making all the difference in an aerodynamic configuration. In the example pictured, the gap is huge, the front of the trailer is essentially a flat 4x8 sheet of plywood. I am grossing about 36k lbs and happy to get 8 mpg.  Put a 53' trailer coupled close with a couple of aerodynamic aids, like side skirts, and low rolling resistance tires and I can get 9.5 mpg, carefully driven. Put a 53' cattle hauler behind me empty and I will be getting 6 mpg.

A car hauler is bad, maybe 5.5 mpg.

But hands down the worst is an open top 53' "tipper", essentially a van designed to transfer garbage with no top. Nets 4.5 in a crosswind. yuck. 

Jeff Beyer temporarily retired from Trailer Transit
2000 Freightliner Argosy Cabover
2008 Work and Play 34FK
Homebase NW Indiana, no longer full time

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Jeff is right about the trailer. When we had the Airstream our mpg was 1+ better than our current Sprinter with a flatter nose cap, consistently. The Sprinter is heavier but I think its the aerodynamics are which plays the most. Since I'm talking travel trailers the distance from BOC remains the same.

Curt

 

 

2001 Freightliner Century, 500hp Series 60, Gen 2 autoshift, 3.42 singled rear locker.

2004 Keystone Sprinter 299RLS (TT)

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