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-   -   Weight Distribution and Tongue Weight (http://www.airforums.com/forums/f464/weight-distribution-and-tongue-weight-100587.html)

AldeanFan 01-22-2013 08:11 PM

Weight Distribution and Tongue Weight
 
Today I found myself in a discussion regarding towing and I wanted to hear from the voice of experience to help me settle the arguement.


Basically the question is this: Does using a weight distributing hitch allow you to pull a trailer with a tongue weight exceeding the vehicle manufacturer's tongue weight rating.

For example:
Vehicle: Towing Capacity 5000lbs, Max tongue weight 500lbs
Trailer: Weight: 4000lbs, tongue weight 700lbs
is this combination acceptable if a properly set up weight distributing hitch is used?

dznf0g 01-22-2013 08:17 PM

I can't speak for all manufacturers, but GM products give two ratings for tongue weight maximums. One w/o WD and one with WD. And the WD maximum is higher than the non-WD rating.

dznf0g 01-22-2013 08:23 PM




For example, here is a Chevy Silverado 1500. 2500 and 3500 have the same rating for both types of hitches.





Weight of the Trailer Tongue


The tongue load (A) of any trailer is very important because it is also part of the vehicle weight. The Gross Vehicle Weight (GVW) includes the curb weight of the vehicle, any cargo carried in it, and the people who will be riding in the vehicle as well as trailer tongue weight. Vehicle options, equipment, passengers and cargo in the vehicle reduce the amount of tongue weight the vehicle can carry, which will also reduce the trailer weight the vehicle can tow. See “ Vehicle Load Limits” for more information about the vehicle's maximum load capacity.

http://gsi.xw.gm.com/image_en_us/gif...91/1991114.gifhttp://gsi.xw.gm.com/newsi/images/tif.gif
Trailer tongue weight (A) should be 10 to 15 percent and fifth-wheel or gooseneck kingpin weight should be 15 to 25 percent of the loaded trailer weight up to the maximums for vehicle series and hitch type.

Vehicle Series


Hitch Type


Maximum Tongue Weight


1500


Weight Carrying


363 kg (800 lb)


1500


Weight Distributing


499 kg (1,100 lb)

SSquared 01-22-2013 11:39 PM

Another example, this one different
 
I have just been reading a the owner's manual for a different vehicle, the GMC Yukon Denali (half ton version). That manual has a table showing a higher allowable weight for a weight-distributing hitch:


Vehicle Series Hitch Type Maximum Tongue Weight
1500 Weight Carrying 272 kg (600 lbs)
1500 Weight Distributing 499 kg (1,100 lbs)


Hope this helps.

Andrew T 01-23-2013 05:29 AM

If you are thinking of setting up your Flex to tow the 23 Safari it will work very well with weight distribution. We have a few dozen of these in service and they are a great tow vehicle, very stable and economical to operate. However the hitch receiver on the Flex is not strong enough to transfer weight properly, this is a common problem even on receivers that are rated for more weight. The good news is that it is fairly simple to strengthen it so that it can transfer weight quite nicely.

Andrew T

slowmover 01-23-2013 06:12 AM

Head over to London, ON, Aldean. Get the hitch receiver squared away / modified by those folks at CAN AM.

dznf0g 01-23-2013 07:03 AM

Red! Your avatar is all crookedy!

slowmover 01-24-2013 06:43 AM

Quote:

Originally Posted by dznf0g (Post 1252368)
Red! Your avatar is all crookedy!

Yeah, new TT pic "correction" and the need to also change my "name". Upgrade membership. Contact a moderator. Stuff I haven't gotten around to, yet.

ROBERT CROSS 01-24-2013 08:36 AM

"Basically the question is this: Does using a weight distributing hitch allow you to pull a trailer with a tongue weight exceeding the vehicle manufacturer's tongue weight rating."

In a word.....No.

As noted it's the hitch receiver that is load rated.

It's the AXLE & TIRE, (trlr and TV) ratings that determine the weight being towed. I see no upside in exceeding either.:flowers:

Bob
:wally:

pappy19 01-24-2013 09:10 AM

What Bob said is the correct answer, it's the hitch that's rated for the weight not just the vehicle itself. While the hitch load/weight rating is probably below the real specification, a more beefy hitch would improve your odds of having a problem. Most over weight hitch problems result in a weld failing , or hitch bolt breaking, and then you are on your safety chains. Either way, it would not be pretty. The smaller the hitch, the less weight it can handle and margin of error increases.

SteveH 01-24-2013 10:01 AM

Kind of reluctant to get into this because of how most tow vehicle vs weight/towing capacity discussions go, but there are actually several weight ratings on tow vehicles, and hitch weights both with and without weight distribution is just a couple of them. Although I would not want to exceed any vehicle weight ratings, especially hitch weight ratings, it seems to me the axle weight ratings are also very important, followed by max payload, and then towing capacity.

Just because a person might install a higher capacity rated receiver hitch on a tow vehicle, does not mean the rest of the vehicle can/will handle the weight. Vehicle manufacturers spend lots of money paying highly educated engineers to calculate these weight ratings, so it seems to me, at least, that they are important.

CanoeStream 01-24-2013 11:28 AM

Quote:

Originally Posted by REDNAX (Post 1252357)
Head over to London, ON, Aldean. Get the hitch receiver squared away / modified by those folks at CAN AM.

I absolutely agree with this -- Andrew T is the PhD of hitch minds.

REDNAX - I rotated your avatar. The rotation probably was caused by EXIF orientation data in iPhones & iPads that non-Apple systems can't interpret. Sometimes a Windoze machine is good for sumpin'. Wish they'd all get on the same page.

Username changes are only done through the Help Desk -- click 'Contact Us' at page bottom and tell us who you'd rather be. Painless... :flowers:

Road Ruler 01-24-2013 11:39 AM

Quote:

Originally Posted by CanoeStream (Post 1252912)

REDNAX - I rotated your avatar.

Looks better. REDNAX is a straight up kinda guy and deserves to have a straight up Avatar.

AldeanFan 01-24-2013 07:19 PM

Quote:

Originally Posted by Andrew T (Post 1252353)
If you are thinking of setting up your Flex to tow the 23 Safari it will work very well with weight distribution. We have a few dozen of these in service and they are a great tow vehicle, very stable and economical to operate. However the hitch receiver on the Flex is not strong enough to transfer weight properly, this is a common problem even on receivers that are rated for more weight. The good news is that it is fairly simple to strengthen it so that it can transfer weight quite nicely.

Andrew T

Thanks Andrew, I was planning to add a brace from the hitch to the subframe, but that can wait until the snow melts.

AldeanFan 01-24-2013 07:23 PM

Thanks for all the good input,

The arguement was wether the weight distributing hitch allowed you to exceed the rating of the vehicle/hitch.

Of course the more I look in to these things the more bad information I find.

The Ford Flex Towing manual shows only one tongue weight rating, and it indicates you must use a weight distributing hitch.

My Tundra Manual provides no information on tongue weight at all!

Jim Flower 01-24-2013 07:38 PM

Vehicle manufacturers spend lots of money paying highly educated engineers to calculate these weight ratings, so it seems to me, at least, that they are important.[/QUOTE]

I agree with you. However, the engineer's calculations are only the start of a process that gets more bungled as each department adds their expertise. The engineers design stuff to work properly. Then the beanies reject the design because it is too expensive and make other engineers change the design to make it cheaper. Then the lawyers have a peak at it and fiddle with the specifications to make sure there will be no liability even if the contraption gets sucked into outer space by aliens. And then the marketing guys put some kind of spin on the resulting mess in order to attract even the most Leary customer. That's where we come. The sales guy takes stock of us and proceeds to tell you what ever is necessary to ensure a commission deposit into his jeans. So now we have a one ton diesel dragging around a 16' Bambi or a Mini Cooper towing a 34' Classic. The specifications have become irrelevant, which is why no insurance company in the US has reneged on paying a claim due to a vehicle towing a trailer that has exceeded the manufacturer's "tow rating". So no wonder its hard to choose your set up. But it sure is nice having the freedom to choose. I chose to go to an expert for help and I am a very happy camper.

slowmover 01-24-2013 09:18 PM

Back to basics, same with Jim Flower. Never exceed tire and wheel ratings. Or axle. The rest is open to how to distribute tongue weight. A WD hitch ought always be able to restore the front axle to it's unhitched weight value. Otherwise, it is not a weight distribution hitch.

As in all these endeavors, actual scaled measurements are what count. Not guesstimates, height measurements, etc. Numbers from a certified scale.

Being painstaking counts. Some experience in the "how to", keep good records, and one is good to go from then on with that particular rig.

.

SSquared 01-25-2013 09:50 PM

One more restriction from owner's manual
 
I was just reading another owner's manual online (can you tell I'm trying to decide on a tow vehicle?), and found the following:
If using a weight
distributing hitch, make sure not to
exceed the RGAWR before applying
the weight distribution spring bars.
That's from page 9-65 of the 2012 GMC Yukon Denali / Denali XL owner's manual.

Most advice I have seen on this forum says to ensure the axle loads are within the limit with the WD tightened, rather than according to what the quote here says. One more thing to worry about, though we know lots of people do fine without worrying over this particular point.

dznf0g 01-25-2013 10:59 PM

Quote:

Originally Posted by SSquared (Post 1253463)
I was just reading another owner's manual online (can you tell I'm trying to decide on a tow vehicle?), and found the following:
If using a weight
distributing hitch, make sure not to
exceed the RGAWR before applying
the weight distribution spring bars.
That's from page 9-65 of the 2012 GMC Yukon Denali / Denali XL owner's manual.

Most advice I have seen on this forum says to ensure the axle loads are within the limit with the WD tightened, rather than according to what the quote here says. One more thing to worry about, though we know lots of people do fine without worrying over this particular point.


hmmmm, that seems to me to be some sort of misprint....I'll look into that. I don't think it matters what the load is PRIOR to "springing up". It's the load as going down the road that matters.

dkottum 01-25-2013 11:10 PM

SSquared, could they be covering the possibility of w.d. hitch failure, dropping that distributed weight back onto the rear axle while moving down the road?

doug k


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