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08-20-2015, 10:28 AM
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#61
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Rivet Master
2016 30' Classic
Lorton
, Virginia
Join Date: Jul 2015
Posts: 689
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Quote:
Originally Posted by bono
And if you look at the torsional stiffness test that both Ram, GMC and Ford continue to do in the frame of their pickups they are laughable; impressive for a frame vehicle which is structurally deficient in torsional rigidity regardless of what steel you throw at it, but laughable when compared to a unibody."
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Quote:
Originally Posted by nrgtrakr
I wasn't questioning a unibody towing. The question stands as written. Rephrased - "How come frame construction can tow so much more than unibody?"
Maybe I missed something, all I saw was 31' AS. Look up the weight for a 31' AS and see what you get. I found a 2013 was 7,254# trailer weight, 805# tongue, 10,000# GVWR.
As you probably know, 7,254# is before options (AC, microwave, battery charger for example) and variable weights (tanks and water heater) - at least that's how AS explains it in 75. Add in food and personal belongings and ...
I chose the high weight on purpose to be safe. But maybe the OP only adds 446# to his when using it, maybe his AS actually weighs less.
But again the main point for me was exceeding the vehicle's capacity.
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Except for the uninformed, torsional stiffness is NOT what you want when designing a vehicle for heavy loads. Ever notice why semi trucks have huge ladder frames and while under load especially from a stop they twist and buck when accelerating? This is by design.
A uni-body pickup truck trying to carry/haul the loads of a body on frame pickup truck would simply snap spot welds, contort and would be destroyed.
Ford tried a uni-body pickup before and it was a disaster. Shortly after the trucks went on sale, buyers discovered that putting heavy cargo in the unibody trucks could cause the one-piece body to flex with interesting consequences. Stories percolating through the Internet tell of uni-body owners who would load their trucks, only to discover that the sills had distorted enough to jam the doors shut. Yet others tell tales of having a fully laden truck twist badly enough to pop a door open when crossing railroad tracks. Age and corrosion only exacerbated issues as the load-bearing bodies began to perforate and rust.
You just can't pile as much weight on it before it begins to twist the entire car body in odd ways. On a ladder frame, the weight is transmitted to the suspension and the wheels in a much more direct, controlled way. "Flex" isn't necessarily an issue, since only the frame is flexing and the body is decoupled and riding on rubber mounts. The HD versions of Ford and Ram's trucks (F350, etc) actually have C-channel frames instead of fully boxed frames, like the 1/2 tons do, because allowing a little flex in the frame actually helps carrying and towing capability.
Uni-body vehicles are fine when used within their design specs. Once you start talking about towing and loads thousands and thousands of pounds above that, I tend to disagree.
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08-20-2015, 10:51 AM
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#62
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Rivet Master
Currently Looking...
Vancouver
, British Columbia
Join Date: Oct 2012
Posts: 4,578
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The OP wrote he has a 2015 30 foot.
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08-20-2015, 11:03 AM
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#63
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Rivet Master
2013 31' Classic
billings
, Montana
Join Date: Feb 2010
Posts: 3,576
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I haven't seen many cars towing travel trailers in Mt., although I've been looking at my wife's Venza !!
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08-20-2015, 11:29 AM
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#64
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Rivet Master
2014 31' Classic
2015 23' International
2013 25' FB International
Apache Junction
, Arizona
Join Date: Sep 2012
Posts: 6,215
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So the printed weight numbers of the door post versus the scales report is the heart of this long conversation. Which numbers are the ones to fudge? I went across the scale in May with the truck and trailer loaded for camping and me and the wife as the people in the truck.
GAWF 5,500 scales 4,700
GAWR 6,010 scales 5,700
GVW 9,600 scales 10,300
GCW 20,000 scales 18,660
So while the GVW was exceeded, the axle and tire with wheel ratings were under the maximum. The maximum combined weight was under the limit and the trailer weight was less than the maximum. This is a truck which is designed to carry loads. Most states DOT officers are only concerned that tire, wheel and axle ratings are not exceeded and the license plate has the correct weight ticket for the load.
The togue weight of the trailer is now reduced to 1,200 pounds in this example, so the trailer typically weighs around 9,300 pounds unhitched loaded for camping.
For us, the truck is properly sized for the job at hand. We have removed a lot of heavy items after this trip that will probably not be carried any more which will reduce the rear axle load some more.
When we saw a used 34' Classic (last one officially built - #25 of 25), I pushed the numbers and my truck could have been easily overloaded with that trailer that had a GVW of 11,500 pounds. Thus we ordered the 31' Classic with a 10,000 pound GVW that was within the towing GCVW restrictions.
__________________
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC
TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell
2014 31' Classic w/ twin beds, 50 amp service, 1000 watt solar system, Centramatics, Tuson TPMS, 12" disc brakes, 16" tires & wheels
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08-20-2015, 11:38 AM
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#65
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Rivet Master
Currently Looking...
Mission
, Texas
Join Date: Jun 2015
Posts: 836
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Quote:
Originally Posted by jcl
The OP wrote he has a 2015 30 foot.
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Okay ...
2013 - 30' AS 7,365# trailer weight, 773# tongue, 10,000# GVWR
Pick nits much?
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08-20-2015, 11:43 AM
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#66
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Rivet Master
Currently Looking...
Vancouver
, British Columbia
Join Date: Oct 2012
Posts: 4,578
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Quote:
Originally Posted by Zybane
Uni-body vehicles are fine when used within their design specs. Once you start talking about towing and loads thousands and thousands of pounds above that, I tend to disagree.
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I don't think the 60s unibody pickup is as relevant. An SUV doesn't have the roof profile of a pickup, it is more of a one box of two box design. A better example would be a Transit or Sprinter. Available up to one ton class ratings. Unibody. Current design. Designed to carry loads. What don't they know?
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08-20-2015, 11:50 AM
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#67
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Rivet Master
Vintage Kin Owner
N/A
, N/A
Join Date: Sep 2012
Posts: 989
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Quote:
Originally Posted by jcl
I don't think the 60s unibody pickup is as relevant. An SUV doesn't have the roof profile of a pickup, it is more of a one box of two box design. A better example would be a Transit or Sprinter. Available up to one ton class ratings. Unibody. Current design. Designed to carry loads. What don't they know?
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A 1 ton Sprinter has only a 5000 tow rating.
I have never seen a body on frame race car nor a unibody semi. They make different tools for different applications for a reason.
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08-20-2015, 12:31 PM
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#68
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Rivet Master
2016 30' Classic
Lorton
, Virginia
Join Date: Jul 2015
Posts: 689
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Quote:
Originally Posted by rostam
A 1 ton Sprinter has only a 5000 tow rating.
I have never seen a body on frame race car nor a unibody semi. They make different tools for different applications for a reason.
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Agreed.
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08-20-2015, 12:50 PM
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#69
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Rivet Master
2012 25' Flying Cloud
Battle Lake
, Minnesota
Join Date: Jun 2009
Posts: 7,714
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The good thing is we see more folks like the Tino's Touareg/Airstream combo all the time who have taken their head out of the sand to understand their is more to safe, comfortable and efficient towing than manufacturer's ratings. Knowing these design characteristics can make all of us choose better tow vehicles, hitches, and Airstream components while still remaining within tow ratings. And for those who wish to push the parameters and do it safely.
__________________
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
The Truth is More Important Than the Facts
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08-20-2015, 01:12 PM
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#70
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Rivet Master
Currently Looking...
K.C.
, Missouri
Join Date: Nov 2011
Posts: 585
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Quote:
Originally Posted by rostam
A 1 ton ( "unibody"....note added by me ) Sprinter has only a 5000 tow rating.
I have never seen a body on frame race car nor a unibody semi. They make different tools for different applications for a reason.
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Correct. And in the "Sprinter class", if we look at a Nissan NV, it has a 8700 lb tow capacity. ......and...... a ladder frame. No unibody there.
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08-20-2015, 05:02 PM
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#71
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Rivet Master
2012 25' Flying Cloud
Battle Lake
, Minnesota
Join Date: Jun 2009
Posts: 7,714
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Quote:
Originally Posted by rostam
. . . I have never seen a body on frame race car nor a unibody semi. They make different tools for different applications for a reason.
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But if you took the best characteristics of both, race car unibody and great full independent suspension and the semi's abundance of low rpm diesel torque along with superior barking ability of either, put them together you'd have a Touareg.
Which at least brings us back to the original topic.
__________________
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
The Truth is More Important Than the Facts
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08-20-2015, 05:36 PM
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#72
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Rivet Master
Currently Looking...
K.C.
, Missouri
Join Date: Nov 2011
Posts: 585
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Quote:
Originally Posted by dkottum
But if you took the best characteristics of both, race car unibody and great full independent suspension and the semi's abundance of low rpm diesel torque along with superior barking ability of either, put them together you'd have a Touareg.
Which at least brings us back to the original topic.
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....and like a LOT of compromises, it would do neither task well !
That's like saying all I need in my toolbox of hammers is a 16 ounce ball-peen.... I can use it to drive either tacks, or railroad spikes......
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08-20-2015, 06:19 PM
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#73
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Rivet Master
Currently Looking...
Vancouver
, British Columbia
Join Date: Oct 2012
Posts: 4,578
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Quote:
Originally Posted by nrgtrakr
Okay ...
2013 - 30' AS 7,365# trailer weight, 773# tongue, 10,000# GVWR
Pick nits much?
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You are getting closer now that you are looking at 30 foot models.
Now look at the Signature, not the Classic. The weights were in post #73.
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08-20-2015, 06:40 PM
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#74
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Rivet Master
Currently Looking...
Vancouver
, British Columbia
Join Date: Oct 2012
Posts: 4,578
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Quote:
Originally Posted by rostam
I have never seen a body on frame race car nor a unibody semi. They make different tools for different applications for a reason.
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Maybe the SUVs like the VW are for those who want something that handles more like a race car and less like a semi, while also being able to tow 7700 lbs or so when required.
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08-20-2015, 07:55 PM
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#75
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Rivet Master
Currently Looking...
Mission
, Texas
Join Date: Jun 2015
Posts: 836
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VW Touareg diesel and 31 foot Airstream
Quote:
Originally Posted by jcl
Now look at the Signature, not the Classic. The weights were in post #73.
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Sure, I'll play along, but only one weight listed in your post and it doesn't match ...
AS says a 30' Signature weighs 6,382# without options or variables, 880# tongue, 8,800# GVWR.
I wouldn't do it. I used to get paid for doing crazy stuff, I'm retired now.
BTW, doing the numbers on our 75 Overlander 27', minimum options and medium variables added about 1,000#.
So this 30' with a GVWR of 8,800# and a 7,700# TV - No thanks!
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08-20-2015, 07:55 PM
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#76
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Rivet Master
2007 27' International CCD FB
San Diego
, California
Join Date: Sep 2014
Posts: 2,115
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Quote:
Originally Posted by Zybane
Except for the uninformed, torsional stiffness is NOT what you want when designing a vehicle for heavy loads. Ever notice why semi trucks have huge ladder frames and while under load especially from a stop they twist and buck when accelerating? This is by design.
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Thank you. And this is why layman are not engineers.
Rigidity, torsional stiffness, strength, and durability are all too often conflated on these forums as singular concepts to justify towing beyond a manufacturers specs.
Fact is, they are at best guessing or justifying why they can tow beyond the manufacturers designed limit without truly understanding the system (because cars are complex systems with compromises to meet particular design requirements) limitations.
Sure you can modify one to suit your use case and I've been known to push boundaries. But some assumptions and justifications on these boards are very flawed, and quite scary to me.
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08-20-2015, 07:57 PM
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#77
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Rivet Master
Currently Looking...
Mission
, Texas
Join Date: Jun 2015
Posts: 836
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VW Touareg diesel and 31 foot Airstream
ditto ...
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08-20-2015, 09:40 PM
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#78
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Rivet Master
Mountain View
, California
Join Date: May 2015
Posts: 573
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This is exactly the reason why I would never drive a pickup. I like X5 which is just all-purpose car for me. It is capable to tow heavy load, despite whining from truck fans. The ONLY concern I will probably have is the constant harassment on the road from the truck drivers... at least this is what I am hearing from German SUV owners towing larger trailers.
Quote:
Originally Posted by jcl
Maybe the SUVs like the VW are for those who want something that handles more like a race car and less like a semi, while also being able to tow 7700 lbs or so when required.
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08-20-2015, 10:02 PM
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#79
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Rivet Master
1972 25' Tradewind
North Vancouver
, British Columbia
Join Date: Feb 2006
Posts: 3,421
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Did I miss where the OP was actually asking anyone for their opinion? Maybe the mods should start a dedicated thread where the truck people can feel free to criticize alternative vehicles so that posts like this one, where a person wants to show off his trailer and TV combo, can do so without it being hijacked by people with nothing better to do than rain on his parade.
__________________
Cameron & the Labradors, Kai & Samm
North Vancouver, BC
Live! Life's a banquet and most poor suckers are starving to death! - Mame Dennis
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08-20-2015, 10:04 PM
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#80
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E Pluribus Aluminus
2008 34' Classic S/O
1967 22' Safari
2005 30' Classic
Land Of Enchantment
, New Mexico
Join Date: Aug 2005
Posts: 1,300
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Quote:
Originally Posted by bono
This is exactly the reason why I would never drive a pickup. I like X5 which is just all-purpose car for me. It is capable to tow heavy load, despite whining from truck fans. The ONLY concern I will probably have is the constant harassment on the road from the truck drivers... at least this is what I am hearing from German SUV owners towing larger trailers.
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Well the issue about towing isn’t just about a machines ability to tow a 5 to 9K lb. rolling weight (or just gas mileage), but it’s ability to do so under all conditions, hills n’ dales and in avoidance situations... safely. My understanding is that an X5 and VW Touareg weigh in at about 4700 lbs. GVW. Most of the trailers we’ve been talking about here have weighed anywhere from over 5K lbs to about 9500 lbs.
Isn’t that a bit like the tail wagging the dog?
I’m pretty much of the opinion to follow directions and stick with what the manufacturer says it’s vehicle is capable of and give it a wide margin of error. It isn’t about trucks vs. minivans vs. tonka trucks or cars. It’s about safety.
I’ve never married myself to a vehicle so much so as to have to have it where I have to make all sorts of compromises to justify it. It can either do the job it was built to do according to the manufacturer or it can’t. If not, find something else. I could care less what they do in Japan, Germany, Canada or Timbuktu.
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__________________
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Jaxon
WBCCI 7005 * AIR 9218
The trouble with trouble is it always starts out as fun...
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