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Question on singling a truck


GeorgiaHybrid

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I ain't gots a college degree in math, but if a single axle truck has 175 sq/in of contact patch, it should follow that a tandem would have a lot more than 180. (175/6=29.16*10=291.6) Plus, that second drive axle brings a lot more than 500# to the party. Plus if 100 psi is correct for your steers then it's way over inflation for the tandem drives(thus bigger contact patch). Plus.....

 

So, I always thought a SWAG was short for "Sophisticated Wild Ass Guess", not "Pulling Random Numbers Out of the Air".

 

It's really not that much harder to use real numbers and thus arrive at a meaningful conclusion. ;)

 

If you've got a problem with my NUMBERS, cough up some better ones.

 

If you want to customize the tire pressures better than my 100 psi average, GO AHEAD. Newton has yet to be proven wrong. Plain and simple: an inflated tire is going to be in equilibrium: the air pressure inside is going to press equally around the tire's inner surfaces, which in turn are connected to the outer surfaces. The tire will deform such that the contact path area times the inflation pressure (times the number of tires on the axle) will equal the scale weight for that axle. A tandem truck, loaded the same as a singled truck, will have the increased weight of an additional axle but further distribution of weight across the additional axle, lowering the weight (on ground) per axle. Braking force is calculated strictly on the "normal force" (the downward component of mass under the influence of gravity, so uphill and downhill conditions do change things) times the coefficient of friction. Want better braking? Change tires to a different compound that offers a higher coefficient of friction. Change ABS systems to one that puts sensors on every axle. Otherwise, it's all going to be a wash.

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Agreed completely. I run 70psi on my tandem drives to get a better contact patch. The truck is more stable. With lockers all around it will go almost anywhere. Better ride than a single, but not as smooth as a Tri.

BIgger contact patch but less weight per square inch in that contact patch. No change in braking. Marginal improvement in acceleration capability (with lockers). However, likely more sidewall flex than if you were running 100psi, which could cause additional heating and resulting risk if the tire's not designed for that pressure. Did you arrive at 70psi from tire manufacturer charts?

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I don't have any real issue with Peety's numbers. It is pretty much a wash on braking, IMO, from what I have seen. Probably a wash, or close to it on traction as well, if you have a locker on the singled truck. Maybe not, but it will be close. In any case, you DO NOT want to make a habit of getting far off road in these trucks if hooked up to an RV. They do not perform well. Can you do it? Sure, anything can be done. But most will not spec out a truck for that application. I build a truck for its "typical" or intended use - not for all the things I could dream up.

 

For ME, on balance considering the application and lifestyle of a fulltimer I like a singled truck. You are not giving up much or any braking, you are not giving up much or any traction (with a locker). For SURE I am avoiding taking the truck "mudding" so I'm not setting it up for that. You get less maintenance singled and you get about an equal ride in my experience (I personally would not say better). You get far more storage on a singled truck. If you position the rear axle correctly you will not overload the front axle except in unusual and extreme circumstances.

 

I don't buy that there is a severe difference in a rear blowout with a singled truck vs. tandem with (lets say) 18K on the rear. I've not seen it, but I'm willing to be educated. Is there a difference? I'd bet there is, but not a great difference. And I'd bet that not such a great difference that handling is so bad as to be dangerous. The only rear blowout I've experienced on a singled truck did not cause ANY handling issues. But that is a one-sample statistic. Like I said, I'll be educated.

 

The biggest downsides to singling are what I said before - cost and lack of weight carrying capacity. These two items need careful consideration in making the decision. The other "handling issues" like traction and ride are a wash - at least to me. But everyone gets to choose - it is YOUR truck, do what you want.

 

On the 680 - that is a fine truck. One I've said many times I would own. If I had to choose between a NEW Volvo 780 and a T680 it would be a difficult choice. I also like the Cascadia. My only knock on the Cascadia is that it seems to me that the cab interior is cheaply put together - even optioned out. I recently rode in one that had 700K miles on it, and it was a rattletrap, akin to the older FL trucks. But new they are impressively quiet.

Jack & Danielle Mayer #60376 Lifetime Member
Living on the road since 2000

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No truck at the moment - we use one of our demo units
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If you've got a problem with my NUMBERS, cough up some better ones.

 

<<big snip>> Otherwise, it's all going to be a wash.

 

I guess my real point, and issue with your numbers, is that more tires need less air pressure to carry a given load. So, dropping the pressures in a tandem will not increase tire flex, rather it will be the same as single axle at the higher pressure.

 

And of course, that means with PROPERLY inflated tires, you'll have roughly double the contact patch with a tandem.

 

Just for grins, I tried to do a search and find the proper pressure for our truck, tandem with a loaded weight of roughly 10k on the drives. The charts I found don't go that low.

 

I have the same problem with some of my tractor tires. The manufacturer charts only go so low (6 psi), and my loads are well below their ratings.

KW T-680, POPEMOBILE
Newmar X-Aire, VATICAN
Lots of old motorcycles, Moto Guzzi Griso and Spyder F3 currently in the front row
Young enough to play in the dirt as a retired farmer.
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Same problem here. Charts go to 70psi, but the correct number is probably more like 40-45. The manufacturers never envisioned a light load application like ours.

George,
Suzuki Celerio 998cc

Yamaha NMAX scooter

 

Work ride is Western Star N2 Tri-Tri tanker at 56,500kg loaded

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"Freightliner category, an affordable throwaway.......lol"

 

Good thing "Grumps" is dead.......IF he knew that those old Freightshakers were supposed to be thrown-away after only a Million miles or so..... Those "throw-aways" were still making $$$$$ after +2,000,000........

 

<<snip>>

 

"Grumps" maybe ran his trucks too long and with too many miles but they kept the beans on the table........he would be amazed that these days most bean-counters consider the life of a HDT near it's end at 750K to 1,000K .........

 

 

 

Ponder on......

 

Drive on..........(sometimes rattles means your still moving......)

 

I'll bet Grump didn't stop running tires because they were 6-7 years old, and I'll also bet he didn't have many tire failures. ;)

 

My thought is modern tires don't last as long, and properly inflated tires will still run a long time past their "prime". That said, I have experienced tire failures when I didn't take the time to check them, or knowingly ran a tire that was only a "little" low. :(

KW T-680, POPEMOBILE
Newmar X-Aire, VATICAN
Lots of old motorcycles, Moto Guzzi Griso and Spyder F3 currently in the front row
Young enough to play in the dirt as a retired farmer.
contact me at rickeieio1@comcast.net

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I don't have any real issue with Peety's numbers. It is pretty much a wash on braking, IMO, from what I have seen. Probably a wash, or close to it on traction as well, if you have a locker on the singled truck. Maybe not, but it will be close. In any case, you DO NOT want to make a habit of getting far off road in these trucks if hooked up to an RV. They do not perform well. Can you do it? Sure, anything can be done. But most will not spec out a truck for that application. I build a truck for its "typical" or intended use - not for all the things I could dream up.

 

For ME, on balance considering the application and lifestyle of a fulltimer I like a singled truck. You are not giving up much or any braking, you are not giving up much or any traction (with a locker). For SURE I am avoiding taking the truck "mudding" so I'm not setting it up for that. You get less maintenance singled and you get about an equal ride in my experience (I personally would not say better). You get far more storage on a singled truck. If you position the rear axle correctly you will not overload the front axle except in unusual and extreme circumstances.

 

I don't buy that there is a severe difference in a rear blowout with a singled truck vs. tandem with (lets say) 18K on the rear. I've not seen it, but I'm willing to be educated. Is there a difference? I'd bet there is, but not a great difference. And I'd bet that not such a great difference that handling is so bad as to be dangerous. The only rear blowout I've experienced on a singled truck did not cause ANY handling issues. But that is a one-sample statistic. Like I said, I'll be educated.

 

The biggest downsides to singling are what I said before - cost and lack of weight carrying capacity. These two items need careful consideration in making the decision. The other "handling issues" like traction and ride are a wash - at least to me. But everyone gets to choose - it is YOUR truck, do what you want.

 

On the 680 - that is a fine truck. One I've said many times I would own. If I had to choose between a NEW Volvo 780 and a T680 it would be a difficult choice. I also like the Cascadia. My only knock on the Cascadia is that it seems to me that the cab interior is cheaply put together - even optioned out. I recently rode in one that had 700K miles on it, and it was a rattletrap, akin to the older FL trucks. But new they are impressively quiet.

The only problem I have with Peety3's NUMBERS is that his entire post is based on theory. The problem with trying to debate something like braking efficiency or tire blow-out safety is the potential variables involved. Rather than get into a drawn out debate, I will suffice it to say that I have never seen or heard of any facts where a single axle truck is safer than a tandem axle truck.

 

There are plenty of folks who have offered up why they chose to pay the added expense to single a truck, that made total and complete sense for them and their application. But as said in an earlier post, since there are so many new people who read these threads as they try to sort out the mystery of big trucks, I hate to see them potentially compromise safety just because everyone else appears to be going that route.

 

For the literalists in the group, I am not saying a single axle truck is not safe.

 

Unlike Jack, I have personal experience with a tire failure in both single and tandem axle trucks and did see a very big difference. The single axle truck had about 7 tons of lumber on a flat bed truck when an outside dual blew. On the tandem truck I had a fully loaded B-Train with 22 tons of hay and hit a piece of scrap metal that came off of a trailer in front of me. On the passenger side, It took out the inside tire on the first drive axle and the outside tires of the second drive axle and first trailer. Of the two events, the second was far more costly from an owner standpoint, but far less mundane from a driver standpoint. With the single axle truck, I wound up in the left lane as the truck rolled right.

John

Southern Nevada

2008 Volvo 780, D13, I-Shift

2017 Keystone Fuzion 420 Toyhauler 

2017 Can-Am Maverick X3-RS

 

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My main reason to single is that I will be adding a Thermo King Tripac to the frame on the right side in front of the axle. That will limit the onboard storage even more. I might be able to get around that by adding a good sized drom box behind the cab and going with a 6x2 or 6x4 configuration. I do know that if I order a new truck, it will be singled up to start with, not have a hitch and the trailer airlines capped (to get out of the FET). I would have to fudge a bit to get the weight rating below the limits to avoid that but it looks possible.

 

If I do get it singled, it will have duals on the back instead of super singles because of the blowout issue. I also run a TPMS system that will watch between my morning checks...I doubt that we will ever go full time and don't need to haul the kitchen sink and all of my ammo so I hope we will be OK on that end....

 

Keep the ideas coming although I'm surprised that someone hasn't suggested a LoneStar yet... Neat looking truck in black but iI just don't like the local dealer...

2017 Kenworth T680
2015 DRV 38RSSA Elite Suites
2016 Smart Prime

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Keep the ideas coming although I'm surprised that someone hasn't suggested a LoneStar yet...

The LoneStar has been discussed here in the past. It's a polarizing design -- it's either loved or hated -- but it's had advocates here since its introduction.

 

I suspect that it's the lack of availability (and possibly at least a minor assist from Navistar's poor emissions control choices, at least for their early EPA10 engines) that's kept someone from converting one to an RV hauler so far.

Phil

 

2002 Teton Royal Aspen

2003 Kenworth T2000 - Cat C12 380/430 1450/1650, FreedomLine, 3.36 - TOTO . . . he's not in Kansas anymore.

ET Air Hitch

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I know where there is a "Original" 1940 REO F-22 with a Gold Comet Six .........ALREADY Singled and boy oh boy can it handle the "load" The rear main leafs are about a foot thick and the over-load leaf stack is another foot thick......right out of a Baldwin Locomotive........oh yes with those springs there is a chance it might have a rattle or two.

 

All kidding a side....... this OLD truck is in a cool service service van configuration with total sides factory fold down tool boxes and this thing is straight......It's complete right down to the original dash / gages and mohair drivers seat.....(ok....... it needs new glass and a couple of mouse traps)

 

It would run if you install a generator..........(who steals a Gold Comet Generator these days....) :ph34r:

 

I would make a KOOL parade rig and............It's Already SINGLED.............. :wub:

 

$2,500.00

 

https://www.flickr.com/photos/springfieldhomer/12529821804

 

You snooze.....you loose.......

 

Drive on ..........(With your......"Old-new".....REO......)

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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I guess my real point, and issue with your numbers, is that more tires need less air pressure to carry a given load. So, dropping the pressures in a tandem will not increase tire flex, rather it will be the same as single axle at the higher pressure.

 

And of course, that means with PROPERLY inflated tires, you'll have roughly double the contact patch with a tandem.

 

Just for grins, I tried to do a search and find the proper pressure for our truck, tandem with a loaded weight of roughly 10k on the drives. The charts I found don't go that low.

 

I have the same problem with some of my tractor tires. The manufacturer charts only go so low (6 psi), and my loads are well below their ratings.

 

Where are you coming up with this claim that more tires need less air pressure to carry a given load?

 

Do you EVER see OTR truckers deflating their drive tires when bobtailing?

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This discussion is getting weird.

 

Have a look at this chart please and explain your reasoning that spreading the load over more tires does NOT indicate you should reduce tire pressures.

 

Just because no one can be bothered setting the correct tire pressure for bob tailing doesn't mean it's right!!

 

http://www.michelintruck.com/en_CA/reference-materials/manuals-bulletins-and-warranties/load-and-inflation-tables/#/

George,
Suzuki Celerio 998cc

Yamaha NMAX scooter

 

Work ride is Western Star N2 Tri-Tri tanker at 56,500kg loaded

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Where are you coming up with this claim that more tires need less air pressure to carry a given load?

 

Do you EVER see OTR truckers deflating their drive tires when bobtailing?

I don't believe that anyone said that you "need" to run less air with more tires for the same load. The whole thing about tire pressures, as depicted in Geo's chart, is that each tire has a maximum load and psi rating, that does not mean that you should run the tire at that maximum pressure, unless you are at maximum tire load.

 

As someone who has been an OTR driver, I will agree that most drivers would not air down when bob tailing. At the same time, an OTR driver who constantly hauled lighter loads would adjust the tire pressures accordingly for multiple reasons, two of which are handling and ride comfort. That might equate to "need".

John

Southern Nevada

2008 Volvo 780, D13, I-Shift

2017 Keystone Fuzion 420 Toyhauler 

2017 Can-Am Maverick X3-RS

 

ALAKAZARCACODEFLGAHIIDILINIAKSKYLAMAMNMS
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I'll bet Grump didn't stop running tires because they were 6-7 years old, and I'll also bet he didn't have many tire failures. ;)

 

My thought is modern tires don't last as long, and properly inflated tires will still run a long time past their "prime". That said, I have experienced tire failures when I didn't take the time to check them, or knowingly ran a tire that was only a "little" low. :(

Your a brave man Rick..........

 

As you may know I am rather shy and meek with my opinions so..........I have held my breath regarding truck tire age and most other "modern-tires" in general...

 

You are fairly on the mark about "Grumps" not having to many tire-failures........however at times operating conditions would result in Failed-Tires......what I mean what is today called "Road-Hazard" and often that would be Railroad spikes in the tires of log trucks........

Many of the main-logging-road-grades in the N W were originally logging-RAILROAD-Grades and when they pulled up the rails sometimes thay would convert the rail-bed into a truck logging road.........here is the catch in the hast to jerk up the tracks thew did NOT collect the spikes.........

 

Try to imagine driving a HDT hundreds of thousands of miles on dirt / gravel roads with MILLIONS of railroad spikes in the road.......

 

You would be amazed how good you get at seeing spikes in the road and dodging them with 18 tires at stake.....

 

Here is the ironic part of the RR grade truck roads ....for the most part the grades were fairly gentile and curves were sweeping BUT you just hated it when ever a road grader bladed the road because a "fresh crop of spikes would be turned up to kill a few tires.

 

For the most part when ever we would operate on RR grades we tended to run second or third generation recaps on all positions except the steers......

 

Yes we often made three generations of recaps on casings and we did not see age related failures ...........some of the casings were a lot older than the "current-tire-time-limits.........something has changed......and not for the better..........

 

Ok flame away at me......... I have my nomex undies on..........

 

Drive on.........(flats happen........)

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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I guess my real point, and issue with your numbers, is that more tires need less air pressure to carry a given load. So, dropping the pressures in a tandem will not increase tire flex, rather it will be the same as single axle at the higher pressure.

 

And of course, that means with PROPERLY inflated tires, you'll have roughly double the contact patch with a tandem.

 

Just for grins, I tried to do a search and find the proper pressure for our truck, tandem with a loaded weight of roughly 10k on the drives. The charts I found don't go that low.

 

I have the same problem with some of my tractor tires. The manufacturer charts only go so low (6 psi), and my loads are well below their ratings.

 

 

This discussion is getting weird.

 

Have a look at this chart please and explain your reasoning that spreading the load over more tires does NOT indicate you should reduce tire pressures.

 

Just because no one can be bothered setting the correct tire pressure for bob tailing doesn't mean it's right!!

 

http://www.michelintruck.com/en_CA/reference-materials/manuals-bulletins-and-warranties/load-and-inflation-tables/#/

I wouldn't say weird...I'd say we're deviating from one argument to a different argument on the fly and forgetting the original debate(s) at hand.

 

 

I've been saying, since the beginning, that a tandem RV hauler won't stop any better than a singled RV hauler. That's from high school physics (not a college degree in math...). In fact, the only reasons that a truck takes longer to stop than a sports car are:

 

1) Different tire rubber compounds have different coefficients of friction.

2) Inherent delay of air getting to brakes (0.5-1 second) compared to incompressible fluid aka brake fluid.

 

Notice that this equation for stopping distance (http://formulas.tutorvista.com/physics/stopping-distance-formula.html) doesn't ask the weight of the vehicle, number of tires, etc. The only thing that's vehicle-specific is the coefficient of friction, which would be tire-dependent.

 

I've also been saying that the size of the contact patch is directly related to the weight bearing on the ground. Add tires for the same weight (i.e. a lift axle actually makes a cleaner argument than tandem vs. single, as a lift axle-equipped truck weighs the same whether the lift axle is up or down), and the total contact patch stays the same. If one of you wants to change your tire pressures to impact the ride quality at that point, go ahead. There's no mechanical/physical correlation between the necessary pressure and the actual weighting, merely a need to meet manufacturer-dictated minimums for the load you carry, and a need to remain at/under the manufacturer-dictated maximum pressure.

 

As far as the chart posted, without any good description around the chart, the only conclusions I can logically draw from it are exactly as written above: don't let the pressure get below X for load Y, and don't let the load exceed A per tire or the pressure exceed B per tire.

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Inflation pressures have a significant effect on both the lateral and longitudinal contact patch dimensions.

 

The manufactures charts provide a guide to the correct inflation pressure for optimizing tire behavior at a given loading.

 

Beyond that, I think we are talking past each other.

George,
Suzuki Celerio 998cc

Yamaha NMAX scooter

 

Work ride is Western Star N2 Tri-Tri tanker at 56,500kg loaded

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Peety, you are wasting your breath.

MY PEOPLE SKILLS ARE JUST FINE.
~It's my tolerance to idiots that needs work.~

2005 Volvo 780 VED12 465hp / Freedomline transmission
singled mid position / Bed by Larry Herrin
2018 customed Mobile Suites 40KSSB3 

2014 smart Fortwo

 

 
 
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I think I know which suspensions to look for now on a Kenworth but how about a Freightliner? I haven't noticed any suspension on them so far on the ones that I have looked at that would appear to be difficult to single up. The ones I have seen were the AirLiner suspension (looks similar to a KW AG400L) and one truck with a Hendrickson Primaax EX air suspension. One option I don't think you can single at all would be a truck with the Chalmers tandem suspension option after looking at a picture of it. Nice looking setup but an all in one with just a single air bag on each side that serves both axles. Anyone know if there would be any major issues with the FreightShaker?

 

I don't think that Volvo has a suspension that would be an issue to single one as they seem to be the most popular but I do know several guys that drive and work on them and every single one complains about electrical issues on them. I don't mind turning wrenches on a truck but I HATE electrical gremlins. One BIG hint about the Volvos is even noted here in this community. One of the classes at the the rally in Hutch is tracking down electrical problems on Volvos.......

2017 Kenworth T680
2015 DRV 38RSSA Elite Suites
2016 Smart Prime

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In the marine company we had some contracts with the Army Corps of Engineers (ACE) to place a LARGE items on some of the Columbia river dams and it involved a short but HEAVY haul by a tractor / trailer on the top-of-dam-roadway with a less than ideal trailer due to space constraints.

 

With +350 ft of concrete below the road bed we did not worry about road-bed carry capacity but the trailer tire load was WAY off the charts.......

I contacted Bridgestone with my problem they said no problem..........just replace ALL of the Alum wheels with steel wheels and then pump up the tires to 180 PSI then DO NOT exceed 5 MPH the tires will be fine and they will handle the load.......

 

Of course ACE would not take my word so Bridgestone drafted me a letter to include in my ACE critical-lift-plan and the Army lowered their guns.....

 

The tire engineers told me that many factors must be considered in tire pressure / load ratings and one of the more critical operations was LOW pressure tire operations and the stress / heat build up when tire pressures are lowered off of the standard charts.......Once in a while we operated with low pressures but speeds were low and travel length was short......

 

Just some things that happen when you work for folks that have guns.......

 

Drive on.........(keep those tires happy......)

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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I wouldn't say weird...I'd say we're deviating from one argument to a different argument on the fly and forgetting the original debate(s) at hand.

 

 

I've been saying, since the beginning, that a tandem RV hauler won't stop any better than a singled RV hauler. That's from high school physics (not a college degree in math...). In fact, the only reasons that a truck takes longer to stop than a sports car are:

 

1) Different tire rubber compounds have different coefficients of friction.

2) Inherent delay of air getting to brakes (0.5-1 second) compared to incompressible fluid aka brake fluid.

 

Notice that this equation for stopping distance (http://formulas.tutorvista.com/physics/stopping-distance-formula.html) doesn't ask the weight of the vehicle, number of tires, etc. The only thing that's vehicle-specific is the coefficient of friction, which would be tire-dependent.

 

I've also been saying that the size of the contact patch is directly related to the weight bearing on the ground. Add tires for the same weight (i.e. a lift axle actually makes a cleaner argument than tandem vs. single, as a lift axle-equipped truck weighs the same whether the lift axle is up or down), and the total contact patch stays the same. If one of you wants to change your tire pressures to impact the ride quality at that point, go ahead. There's no mechanical/physical correlation between the necessary pressure and the actual weighting, merely a need to meet manufacturer-dictated minimums for the load you carry, and a need to remain at/under the manufacturer-dictated maximum pressure.

 

As far as the chart posted, without any good description around the chart, the only conclusions I can logically draw from it are exactly as written above: don't let the pressure get below X for load Y, and don't let the load exceed A per tire or the pressure exceed B per tire.

 

 

I'm not sure if I understand the discussion of the safety factor of being singled or tandem. Seeing that I never took physics in school and all the numbers would be confusing to me if I were to read them. The only thing I have to say is get in a truck with single drive and a truck with tandem drive axles and do a panic stop and see what happens. I vote for the tandem drive, as when I bobtailed a single drive my A$$ would pucker a bit, mix in a little rain and there's an A ticket ride for sure. That being said most of my "bad" experiences were before ABS.

Ok to all you old geezers out there, who remembers the old 121 brake system "early ABS". Hooking up a set of triples and heading out through the Nevada desert and wonder what the set was going to do if you hit the brakes. Part of the set would have the 121 system and some without and they didn't play well together.

"It is better to have more truck than you need than to need more truck than you have"

2001 Volvo 660, Cummins 400 ISX, Eaton 3 Peddle Auto Shift    
2014 Fuzion 40' Toyhauler
2015 Smart Car                                                                                                                                                                          

                                                                                                            

 

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Keep the ideas coming although I'm surprised that someone hasn't suggested a LoneStar yet... Neat looking truck in black but iI just don't like the local dealer...

HERE is your Lonestarhttps://photos.google.com/photo/AF1QipPyCrj3nnsqdDXcDlRW8Vxmv64agoWu343WRmE-

Jack & Danielle Mayer #60376 Lifetime Member
Living on the road since 2000

PLEASE no PM's. Email me. jackdanmayer AT gmail
2016 DRV Houston 44' 5er (we still have it)
2022 New Horizons 43' 5er
2016 Itasca 27N 28' motorhome 
2019 Volvo 860, D13 455/1850, 236" wb, I-Shift, battery-based APU
No truck at the moment - we use one of our demo units
2016 smart Passion, piggyback on the truck
-------------------------------------------------------------------------
See our website for info on New Horizons 5th wheels, HDTs as tow vehicles, communications on the road, and use of solar power
www.jackdanmayer.com
Principal in RVH Lifestyles. RVH-Lifestyles.com

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Anyone know if there would be any major issues with the FreightShaker?

 

Freightliner's AirLiner (FAS II) suspension, which is almost certainly the most commonly installed suspension for on-highway DTNA products, is easily singled. The suspension components for the front and rear axles are not interconnected, and it has outboard-mounted shocks. Drop out the power divider axle, take the remaining rear axle and its AirLiner suspension components and set it at your preferred position.

 

That's how my T2000 was singled, since Scrap was dragging his feet on the development of the AG230 back in the day. ;) I traded a junkyard my tandem set on an AG200 suspension for the rear rear axle out of a FAS II-equipped Freightshaker.

Phil

 

2002 Teton Royal Aspen

2003 Kenworth T2000 - Cat C12 380/430 1450/1650, FreedomLine, 3.36 - TOTO . . . he's not in Kansas anymore.

ET Air Hitch

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I don't have any real issue with Peety's numbers. It is pretty much a wash on braking, IMO, from what I have seen. Probably a wash, or close to it on traction as well, if you have a locker on the singled truck. Maybe not, but it will be close. In any case, you DO NOT want to make a habit of getting far off road in these trucks if hooked up to an RV. They do not perform well. Can you do it? Sure, anything can be done. But most will not spec out a truck for that application. I build a truck for its "typical" or intended use - not for all the things I could dream up.

 

For ME, on balance considering the application and lifestyle of a fulltimer I like a singled truck. You are not giving up much or any braking, you are not giving up much or any traction (with a locker). For SURE I am avoiding taking the truck "mudding" so I'm not setting it up for that. You get less maintenance singled and you get about an equal ride in my experience (I personally would not say better). You get far more storage on a singled truck. If you position the rear axle correctly you will not overload the front axle except in unusual and extreme circumstances.

 

I don't buy that there is a severe difference in a rear blowout with a singled truck vs. tandem with (lets say) 18K on the rear. I've not seen it, but I'm willing to be educated. Is there a difference? I'd bet there is, but not a great difference. And I'd bet that not such a great difference that handling is so bad as to be dangerous. The only rear blowout I've experienced on a singled truck did not cause ANY handling issues. But that is a one-sample statistic. Like I said, I'll be educated.

 

The biggest downsides to singling are what I said before - cost and lack of weight carrying capacity. These two items need careful consideration in making the decision. The other "handling issues" like traction and ride are a wash - at least to me. But everyone gets to choose - it is YOUR truck, do what you want.

 

On the 680 - that is a fine truck. One I've said many times I would own. If I had to choose between a NEW Volvo 780 and a T680 it would be a difficult choice. I also like the Cascadia. My only knock on the Cascadia is that it seems to me that the cab interior is cheaply put together - even optioned out. I recently rode in one that had 700K miles on it, and it was a rattletrap, akin to the older FL trucks. But new they are impressively quiet.

Plenty of points to ponder and....... I own a single as well as a tandem so..... I guess I am blessed or cursed buy what I might be doing with whatever truck I am driving at the time...

 

Fast forward to yesterday Dolly-moma decides it is THE day to go get a ton of hay for Dolly.......no problem we will just take the four horse trailer and place the ton of hay in the front of the trailer since it was sprinkling rain.

 

So......with a ton of hay in front of the trailer it will be very front end heavy......no problem we will not use the pickup we will just use the Freightshaker........ya right.......

 

Well some dummy (me) parked the trailer off the side of the shop driveway that is on a small sloping grade with about a 6 inch shoulder grade to the level pad where the trailer was parked about 45 degrees to the driveway.........no problem......

 

So I kick the tires and light the fire and back down the shop driveway and turn around and then start backing across the driveway at a 45 degree to hitch-up the trailer..........ease back....back....back.......and the darn thing just quits backing about a foot short of the trailer........

hummmm.......check left foot ok the clutch is out.......check shifter......ya it feels like reverse........check drivers mirror......rear driver is spinning....check pass mirror and front driver is spinning.......well it appears the spider gear test is complete.......so .....no problem.......just clutch in heel the service brake to stop the spinning wheels and flip the interlock and all will be well.........interlock flipped on ease the clutch out and ..........."Huston, we have a problem"........It seems that the interlock was doing it's job and the front outside driver tire was "doing it's job" and the pass outside rear driver was "doing it's job" ........but the "JOB" seemed to be more akin to mining a pair of holes rather than moving the "Shaker"..........OK.........time for a little "mind over matter".........just clutch in shift to 1st gear and ease forward.........same hole digging action..........hummm.........I guess the "little mind over matter" works for most people but my mind is just too little.........

 

So........as a famous Brit engineer told me......"well chap, when you find yourself in a hole......quit digging".......

 

I shut the Shaker down and thought about going back into the thread to the mid-level math portion to calculate how deep the holes would be as the Shaker TRENCHED ditches across the driveway to the point where ALL EIGHT driver tires where back in ground contact........

 

Dolly-moma was NOT impressed........so........forget the math.......forget digging bigger holes........just go get a chain and the Bobcat and attach to the front Shaker tow hooks and the Bobcat tow-hooks and then have Dolly-moma GENTLY ease the Shaker forward until the rest of the tires were back in ground contact (and out of the holes)..........Ok.......no problem........drive the Shaker out onto the main driveway and run the Bobcat and slip the bucket mounted ball into the trailer hitch back up over the shoulder of the shop driveway tow the trailer over to the Shaker and drop the trailer and then take the Bobcat over to the shop driveway and use the bucket to fill in and smooth the two "Shaker-holes"

go put the Bobcat back in it's shed, then hitch-up the Shaker to the trailer and go get the Dolly-hay...........No problem......... :wacko:

 

Back in my childhood none of our tandem tractors were as light as these RV rigs are bobtailed so we had the wheel on the ground in a twist......modern air suspension is optimized for highway use in general so less than level surfaces can be a challenge at times......

 

Would the Shaker extract itself over the driveway......sure but I did not need the tank-trap trenches or clutch abuse........

 

Perhaps I am too dumb for a Smartcar.......but maybe..... I should consider just crawling the Bobcat on the back of the Shaker......who needs ramps......

 

Single or tandem???

I can get them all stuck......

 

Ain't horse-RVing fun...........

 

Drive on.........(stay out of the holes)

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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