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Old 12-02-2011, 08:00 AM   #81
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Quote:
Originally Posted by easplund View Post
In general, I thought that SUV's were heavier than pickups. They have a lot more to them than an empty bed in the back. Anyways, at ~6000#, I think that mine is.
Depends on the particular car. Here's some (empty, but with fuel) curb weights of light-duty tow vehicles. Notice that the curb weights of some modern car-based SUVs come really close to the weights of some pickups.

Minivans:
2005 Honda Odyssey: 4615 lbs
2011 Toyota Sienna (V6, front-wheel-drive): 4445 lbs
2011 Chrysler Town and Country: 4685 lbs

"Smaller" trucks:
2005 Toyota Tacoma (crew cab, V6, 4x4): 4115 lbs
2005 Honda Ridgeline: 4540 lbs

Car-based SUVs:
2005 Mercedes ML350: 4845 lbs
2008 Buick Enclave: 5100 lbs
2011 VW Touareg TDI: 5060 lbs
2008 Mercedes GL320: 5655 lbs
2011 Jeep Grand Cherokee (4x4, 3.6-liter V6): 4930 lbs

1/2-ton trucks:
2011 Ford F150 (crew cab, Ecoboost, 4x4): 5705 lbs
2009 Chevrolet Silverado 1500 (crew cab, 5.3-liter, 4x4): 5370 lbs
2009 Dodge Ram 1500 (crew cab, 5.7-liter, 4x4): 5480 lbs

1/2-ton truck-based SUVs:
2007 Chevrolet Suburban (4x4, 5.3-liter): 5935 lbs
2008 Toyota Sequoia (4x4, 5.7-liter): 6025 lbs
2007 Ford Expedition (4x4, 5.4-liter): 6325 lbs

And for some of CanAm's more interesting set-ups:
2010 VW Golf TDI: 3165 lbs, towing a 16' Sport (that weighs about the same as the VW)
2008 Mini Cooper Clubman: 2780 lbs, towing a Argosy 20' (that weighs about the same as the Mini)

Tom
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Old 12-04-2011, 10:34 AM   #82
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Prudence

I think we'd all agree that being prudent is the answer to any of the questions raised above. What specifically constitutes prudence is the sticking point.

TV & RV manufacturers are in business to make money. Period. On safety questions (part of the confusion in these threads) their record is execrable. And SAE is a captured group: given definitions to work within, they will . . even if it means the "answer" given is not comprehensive. It will only be workable within defined parameters. Change the parameters -- any of them -- and different answers will arise.

So, to be specific, "tow ratings" are among a pre-selected group of vehicles. Not all vehicles. An enormous difference. And, if one only chooses a single trailer type with which to conduct tests -- with low COG, no appreciable side or length wind loadings, just frontal -- how can it be said to be "comprehensive"? Does anyone here think that a construction trailer loaded with sheet steel handles the same as a high ground clearance, enormous sail area square white box? I didn't think so. But the hoopla around J2807 would have you believe so.

For the pickup trucks chosen as the focus of this standard, for the commercial operators and contractors, farmers and ranchers, the J2807 guideline may well be worthwhile. But it is only by a leap-of-faith extrapolation to a variety of RV's behind pickups and their closest cousins that the ratings are valid. The farther one is from the test vehicles, and the conditions, the less the "validity".

Pickup trucks (and derivatives) are the worst handling, most dangerous type of vehicle to own and operate. The propensity to rollover is unacceptable. That is the trade-off to the payload and trailer towing capacity wanted for working vehicles. They are better than they used to be . . but it means they are still handicapped in all areas of performance. It's pretty easy to lose traction at the wrong time.

So, that a pickup can do a lot of work is a given. And standards that make comparisons among them a bit more valid are worthwhile is understood. But J2807 makes no attempt to test the range of vehicles for sale, with a variety of trailers, and then add footnotes for performance limitations.

There is also no definition of what constitutes a "good" versus a "bad" trailer. We've all seen the A/S video on the handling characteristics of a leaf-sprung square SOB and a I-S A/S through the same road course. It's simple enough to understand that a crap trailer behind the crappiest-handling TV (a pickup) is the worst combination on the road. Or it ought to be so understood. The TV, not the A/S trailer, is the weak link when the TV is a pickup (see the same trailer faster through the slalom on CAN AM's website behind other TV's).

One can go back in time with older SAE papers and see the same effect. Poorly chosen TV's with poorly-done "hitch rigging" (air shocks, anyone?). If there has ever been a recommendation by SAE for what constitutes the best hitch rigging for a given TV with a variety of TT's (and other) then it's as well hidden as aliens at Area 51. This would more properly be the role of government (DOT) . . but, as that might hurt the profitability of RV and TV manufacturers, it doesn't happen. Some government drone might not get that private sector job later. Other countries have different experiences (and some danged good ideas in some instances, such as mandatory trailer parking brakes). This is where the desire for clarity would happen, if it did.

"Safety" is hard to define, but profit is easy to understand. One may think it cynical, but it is the only rational response to obviously exclusive "testing". Short of an examination of the assumptions underlaying the OEM's idea of "safety" it's what we're left with. The less information, the better, apparently.

As to exceeding the ratings themselves, well, every day in probably every state of the Union are dually 1-T pickups running the roads, perfectly legally, grossing 10,000-lbs or more beyond manufacturer towing ratings for those trucks. And those trucks will do it 24/7/365 for over 300k miles. The states look for properly tagged/apportioned licensure, insurance and that axle/tire ratings are not exceeded. That's about it.

Having done this work -- oilfield hotshot -- with a 1T dually and a gooseneck flatbed trailer (8k empty) and with loads of up to/around 16k on top of the trailer one has to have an idea of how to load what/where. So what does this have to do with RV's? After all, RV's are essentially static for weight, size, etc. Nothing much changes outside of a given range. Thus, an RV is easily predictable. Unchanging. No CDL experience required on every trip outbound.

Those who are quick to criticize AndyT's approach are also those too lazy to have read what he has written, I'll wager. In more than one post or Internet available article he has laid out how an analysis of a TV works within the numbers, overall. No differently than was done by many in the 1960's and 1970's with cars pulling trailers.

The TV manufacturer gave a recommendation. Often easily exceeded provided one was aware of deficiencies which most often could be properly addressed. More easily done today due to the proliferation of accurate 3-pad weight scales nationwide. But what was true then is true now: probably 90% of tow rig combos aren't properly hitched. A little bit, or a lot. Those quick to criticize may also be those who haven't ever adjusted according to scale numbers, and/or those who don't trend changes to the vehicles via numbers and new adjustments the same way.

The weight differences trip to trip in a TT are minor, rarely 1,000-lbs, more likely 100 to 300-lbs trip to trip. So, predicting what works, and having set up ten thousand or more tow vehicles in forty years is a database of experience based on analysis that makes for decent advice. Comprehensive advice.

Then, to say (as has been said here ad nauseum) that one's insurance company will not cover an overweight situation (and that is about legal definitions, not private party "ratings") is the same as saying that running the road at 73-mph means an accident (of even partial liability) will not be covered, is hogwash. That insurance company would be facing a devastating loss and action by the state besides. Fraudulent coverage.

What may "go" in a civil suit is different. So if someone has information concerning those, please affix a link. I've only seen rumors. Closed settlements constitute "rumor", thus no weight there. A democracy wouldn't allow closed court settlements (risk entailment), so you are on your own as regards where we live, or what you deserve to know. A non-starter thus far.

So prudence is for many a matter of both comfort and effort. For those wishing to avoid the latter in favor of a blinded former, stick with what is no more "proven" (ratings) and drive on. 90% with less-than-ideal-hitch-rigging covers pretty much all of us on any given day . . . and so should make pre-trip and post-trip rig inspections more rigorous.

But saying something cannot be done when it is being done and being done well fails the test implied. As well as what the law addresses and doesn't.


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Old 12-04-2011, 12:53 PM   #83
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Thanks very much for this article, Rednax.

It should become required reading for all that get involved in discussions regarding what can pull what.

Thanks for my "Word of the Day", execrable meaning: abominable - odious - loathsome - abhorrent - detestable
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Old 12-05-2011, 09:03 AM   #84
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Great Discussion everyone!

In fairness to the car makers they are in a very difficult position. When we set up a combination we pretty much have control of the entire combination. We know how the trailer handles, what the real weights are, we configure the hitch and we speak with and often take a test drive with the person that is going to drive it. Often we have towed with that combination or one close to it before. I would never make a blanket statement like an automaker that this vehicle can tow all trailers of this weight, weight is part of the equation but balance suspension and aerodynamics are far more important. Likely 75% of the trailers on the road that weigh 4000 pounds do not handle as well or stop as quickly as a 34' Airstream. A discussion that happens all the time at our store is yes you can tow that 34' Airstream but no you cannot tow that 26' box over there.

J2807 is likely a good thing I have followed it closely and was a liason on the committee. I don't care for their handling test it is not really a valid one in my mind. The high speed one involves turning the steering wheel 180 degrees and immediately back to centre. From what I see of it the problem is that it does not account for differences in wheelbase or steering gear ratios. This maneuver in a Ford Crew Cab long box produces a very mild reaction and change in direction. In a Mustang it is a very dramatic change in direction. So even as solo vehicles the Crew Cab can likely do the maneuver at a much higher speed than the Mustang. Hoever if I am trying to avoid an accident give me the Mustang every time.

My concern is that the vehicles tested are only rated to their lowest number but you won't be told what the limiting factor was. For example a Enclave likely beats the pickups and traditional SUV's in the handling test but it may not be able to pass the cooling system test. I might say well I don't plan to visit Arizona in July and I would rather have the handling and the fuel economy but you won't get to make that decision based on the published standard. Another anomoly is that dual wheel trucks are given more time in their 0-60 acceleration standard. So a dually could have a higher tow rating based on that alone but if you did not need the weight carrying capacity a single wheel would do the job just as well just not have as high a rating.

All in all it is possibly a step in the right direction it will keep some of the rediculous ratings out of the mix like 7200 pounds on a 4Runner but if they don't test a vehicle it does not mean it won't tow you just don't have their blessing which is understandable.

I delivered a Fifth Wheel to Florida last week. My 25th trip down I75 each one with a different combination. I towed a 30' Classic back so I had to tow it with our 3/4 Ton Dodge Hemi with 4:10 Gears. Coincidently the last time I drove to Florida was with our 300C also with a Hemi towing a 34 Classic with 4 people in the car and a fully loaded trailer. What amazed me was how much worse the performance was with the truck. Though the truck is heavier than the 300 the trailer had to be 2000 pounds lighter. So though I was moving less weight in total the perfromance was still dramatically less with the the truck with the same engine and 5 speed transmissions in both. Off the line the truck was as good but hills the 300 would sail over at 70 MPH had the truck down to 60 and a gear lower, the truck would have gone over them at 70 but it would have meant climbing at 4500 RPM in 3rd gear. Also I found myself driving the truck in a much more timid fashion as I just did not have the depth of control that is there with 300. Kind of in the back of my mind all the time was "push this too far and it won't come back" kind of a feeling. Not that that is an all bad thing I likely should be more timid when I drive. If halfway back some said here you can take this 300C with 1000 pound tow rating the rest of the way home I would have given up the 3/4 in an instant. Besides the difference in stability the level of comfort in the 300 is dramatically different.

I hope this helps.

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Old 12-05-2011, 09:52 AM   #85
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All in all it [J2807] is possibly a step in the right direction, it will keep some of the ridiculous ratings out of the mix . . . .

If they don't test a vehicle it does not mean it won't tow, [it only means that] you don't have their blessing . . which is understandable.
(edited)

Well put. I figure any vehicle can tow something as a way of approaching from a different direction; to lend perspective to the larger question of prudence.

But it's darned hard to shoot straight up the middle and hit the target with info currently available.


Likely 75% of the trailers on the road that weigh 4000-lbs do not handle as well or stop as quickly as a 34' Airstream. A discussion that happens all the time at our store is, yes you can tow that 34' Airstream, but no you cannot tow that 26' box over there.

An eye-opener for the SWB/leaf-spring crowd thinking the braking, handling dynamics and wind pressure problems between the two types are a matter of styling, not engineering. An A/S 34' can get up to 11,000-lbs, a 26' of any brand is unlikely to be close. (But give New Horizons a chance, they probably could do it with the right customer )

I'd bet that 75% is generous as an estimate.

An A/S (or another aero, I-S, low COG trailer) means that there is a wider range of TV's as valid choices for a given size.

Thanks, Andrew T


2012 New Horizons Majestic. 102" wide . . any guesses on weight? (price?)
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Old 12-05-2011, 10:02 AM   #86
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Wow, I'm learning a lot - thank you especially Andy and Rednax!
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