W/D question

[RLS]

OK, I am having trouble figuring out what is right on what is the actual tongue weight put on the TV after connecting it all up. Below is a quote from the Airstream manual:

When a trailer is hitched up properly to a tow vehicle with a load equalizing hitch, approximately 1/3 of the trailer's tongue weight will be on the trailer's axles and 2/3 will be transferred to the tow vehicle, 1/3 of this weight transfer will be carried by the front wheels and 1/3 by the rear wheels of the tow vehicle (See diagram), Thus, the tire load of each wheel on the tow vehicle will be increased by 1/6 of the trailer's tongue weight. The tire air pressure of the tow vehicle should be increased to compensate for this additional weight. Refer to the vehicle's owner’s manual for this information.

If I am understanding this right, if you have a tongue weight of 900 lbs, after you connect it up correctly, you end up with 595 lbs on the TV and 306 added back to the trailer weight?

This is very confusing any help on understanding this is appreciated.

Bob

[Inland RV Center, In]

Originally Posted by RLS

OK, I am having trouble figuring out what is right on what is the actual tongue weight put on the TV after connecting it all up. Below is a quote from the Airstream manual:

If I am understanding this right, if you have a tongue weight of 900 lbs, after you connect it up correctly, you end up with 595 lbs on the TV and 306 added back to the trailer weight?

This is very confusing any help on understanding this is appreciated.

Bob

That's sort of correct.

The 2/3 of the weight transfered to the tow vehicle (600 pounds) should be divided equally between the front and rear axle of the TV, or in this case 50% to each.

The 1/3 and 1/3 on the tow vehicle only makes sense, if you refer back to the original 900 pounds.

That weight distribution, becomes as perfect as you can get.

The next question, that the manual does not cover, is that the tongue of the trailer must easily bounce, within reason, for proper control.

Over hitching, bars that are way too heavy duty, can also transfer the correct amount of weight, but they will not bend as they should, which in turn will not provide the soft ride that Airstream trailers demand, or else.

Andy

[mustang]

I always just made sure the whole rig was level and the ball was at 19.5 inches and I have always been fine. 10 percent on the pin keeps it from swaying

[tinbender]

I get the distribution to all the wheels but there is another part of the w/d puzzle that I have often wondered about. Are all spring bars the same length?

Since the hitch and w/d setup has to be adjusted to fit an individual trailer and TV, is it acceptable for the spring bars to be shortened if that is the only way to get a vertical hang on the chain? For instance, say you couldn't move the brackets back any further due to gas bottles, battery location or whatever.

How would you fix it if it's not good to shorten it?

Inquiring mind,

TB

[Inland RV Center, In]

Originally Posted by mustang

I always just made sure the whole rig was level and the ball was at 19.5 inches and I have always been fine. 10 percent on the pin keeps it from swaying

There is NO correct ball height, except your trailer.

Ball height is a function of how good the axle may be, it's starting angle, and the load in "your" trailer, plus the year of the trailer.

All of those can and do change the ball height.

Some people ask "what should the ball height be," only to find out their trailer is not level as it should be, if they use as an example 19.5 inches.

The factory ball height in the manuals, is for a brand new trailer, with zero payload.

Andy

[Inland RV Center, In]

Originally Posted by tinbender

I get the distribution to all the wheels but there is another part of the w/d puzzle that I have often wondered about. Are all spring bars the same length?

Since the hitch and w/d setup has to be adjusted to fit an individual trailer and TV, is it acceptable for the spring bars to be shortened if that is the only way to get a vertical hang on the chain? For instance, say you couldn't move the brackets back any further due to gas bottles, battery location or whatever.

How would you fix it if it's not good to shorten it?

Inquiring mind,

TB

What brand hitch do you have? If the chain is attached to the end of the bar, then you must use it that way. Or, if it's a Reese, then add the dual cam to the bars. Then it doesn't matter if the chains are vertical or not.

DO NOT attempt to shorten the bars.

If, when in a straight line, the chains are not vertical as they must be, then you can move the LPG tanks and the tank bracket.

Load equalizing bars, torsion or bend, MUST NEVER BE REDUCED, when traveling.

When the chains are not vertical, then as you make a turn, one bar will bend more and the other bar will bend less. That is not a good situation.

As you turn, both bars must increase the stress on them.

Andy

[RLS]

Andy,

From what I have been reading on here, you are the man! Your reply is the one I had hoped for. So my understanding is right from what you have stated. I also have been reading your replies as to what weight bars to get, so my 1,200 lbs. ones are sitting on the shelf (new) with the 800lbs. ones now ready to hook up. I'm still unsure if these are too much from what you have been talking about. I will be doing the bounce test to see! LOL Just so you know, (I know I am going to get blasted for this) I have an Infiniti QX56 SUV that will be hauling a 2004 25 classic. Load capacity of the QX56 is 1,274lbs (passengers and cargo). QX56 GVWR is 7,100lbs. and a Gross Combined weight (SUV and trailer) of 14,822lbs. Tongue weight is right around 875Lbs. and GVWR of trailer is 7,300lbs., dry is 6,050lbs.
I know this not an ideal set-up, but it will have to due. My main concern was the 1,274lbs. part. but since only roughly 600lbs. tongue weight is actually going onto the SUV, I am OK. Passengers and cargo will be no more than 500Lbs.

Thanks again for the reply

Bob

[tinbender]

Andy,
Thanks for the good info. I have a Reese but I'm not referring to mine. I just wondered about the bars because each hitch setup seems to be unique to each trailer and TV. That being the case, I didn't know if there is a standard length based on tongue length or some other chosen measurement. In looking at different systems on manufacturer's websites I have never seen bar length specified.

Always something to learn.
Thanks again,

TB

[mustang]

Andy does have some good info, I have learned alot today from him. I think I am going to start drinking Pineapple juice, and listening to Hawian music.

[Inland RV Center, In]

Originally Posted by mustang

Andy does have some good info, I have learned alot today from him. I think I am going to start drinking Pineapple juice, and listening to Hawian music.

MAHALO

But if you want really enjoy the music, it's Hawaiian. LOL

Andy

[Ron Gratz]

I believe the 1/3, 1/3, 1/3 tongue weight distribution "guideline" is one of those towing myths which sounds good; but seldom, if ever, is actually achieved. And, such a distribution, if it could be achieved, probably is not desirable.

Some TV manufacturers specify that the WD system should be adjusted so that the front of the TV is returned only to the unhitched height. This implies that the load on the front axle should be returned only to its unhitched load. I.E., none of the tongue weight should be on the front axle.

Many reports of measured axle loads suggest that, after application of weight distribution, the tongue weight is more likely to be distributed about 0%/75%/25% on the front axle, rear axle, and TT axles respectively. Very few people have been able to get more than about 10% of tongue weight transferred to the front axle.

If one considers that a typical TV might have its front/rear axle load at 55%/45% before the TT is attached, then having the tongue weight equally distributed to the front and rear axles would not produce the recommended equal front/rear axle load when towing (which might be another towing myth).

A 1/3, 1/3, 1/3 distribution only is possible for some very specific combinations of TV wheelbase, TV ball overhang, and TT ball to axle distance. More realistically, if you had a TV wheelbase = 130", ball overhang = 65", and ball to TT axles = 195" (just to pick some easy numbers), you would need to transfer 40% of the tongue weight to the TT axles in order to get an equal 30%/30% on the TV's front and rear axles.

A WD system probably cannot (and, should not) transfer more than about 30% of the tongue weight to the TT axles. In this case, and for the above dimensions, the net result after WD is applied would be to have a tongue weight distribution of 10%/60%/30%.

If the WD system transferred 25% to the TT axles, the net distribution would be 0%/75%/25%.

Many people have reported being quite frustrated when trying to achieve a 1/3, 1/3, 1/3 distribution or even just an equal distribution of tongue weight to the TV's front and rear axles. For the vast majority of TV/TT combinations, neither of these objectives can be achieved.

Ron

[dpandorf]

I think the proper procedure starts with ball height in relation to the trailer when its level. Then when you connect the trailer the weight of the trailer pushes down on the rear of the TV. You then use WD to get the trailer back to level. Once you do that the weight will be properly distributed to the rear of the trailer and to the front axle on the TV.

But it starts with the proper ball height.

If this is not correct please correct my analogy.

My current setup has these results:

Front Axle 5240 lbs, Rear Axle 5200 lbs and the trailer 7540 lbs.

I have a 2000 Classic with a GVWR of 9800 lbs.

I have not weighed my truck without the trailer nor I have I weighed the trailer not connected to the truck.

[2airishuman]

i agree the rule of 3rds is history if not myth.

it may have been important or useful in the sedan daze of towing when lifting the drive axle was possible...

or in the single axle short trailer era.

and it might be useful in learning how w/d gear works initially

but even then i see no evidence of it working neatly as suggested.

i've weighted my rig dozens of times with different w/d bar ratings...

and a variety of tensions ON those bars...

UNDER max bar flex and max bar rating, and with the trailer tongue bending under the stress...

only about 150-200 lbs of a 12-1400lb tongue mass shows up on the trailer axles.

what happens at the tv axles is greatly confused. that confusion is increased by NOT weighing the tv un hitched.

it should be obvious that 50/50 on the tv axles hitched isn't equal distribution of the tongue mass...

but it isn't obvious for most of us at first thought.

cheers
2air'

[dpandorf]

Originally Posted by 2airishuman

...

it should be obvious that 50/50 on the tv axles hitched isn't equal distribution of the tongue mass...

but it isn't obvious for most of us at first thought.

cheers
2air'

Do you think its possible I may have my springs too tight? My F250 has a GCWR of 10,000 pounds.

My current setup has these results:

Front Axle 5240 lbs, Rear Axle 5200 lbs and the trailer 7540 lbs.

I have a 2000 Classic with a GVWR of 9800 lbs.

My trailer is level after adjusting the W/D and getting these weights.

[Inland RV Center, In]

Originally Posted by Ron Gratz

I believe the 1/3, 1/3, 1/3 tongue weight distribution "guideline" is one of those towing myths which sounds good; but seldom, if ever, is actually achieved. And, such a distribution, if it could be achieved, probably is not desirable.

If one considers that a typical TV might have its front/rear axle load at 55%/45% before the TT is attached, then having the tongue weight equally distributed to the front and rear axles would not produce the recommended equal front/rear axle load when towing (which might be another towing myth).

Many people have reported being quite frustrated when trying to achieve a 1/3, 1/3, 1/3 distribution or even just an equal distribution of tongue weight to the TV's front and rear axles. For the vast majority of TV/TT combinations, neither of these objectives can be achieved.

Ron

I disagree.

Theory and math don't solve the problem.

Get out in the field, as I have for 42 plus years, and the myths and theory's generated from ideas, is the very thing that causes "MASS" confusion over something so simple and basic that some people insist in making a formula as complicated as the atom bomb, for it.

What your saying "can't be done", I have done thousands of times, over and over again.

Is it always possible? No. Why? because some owners want to have Queen Mary tow vehicles, when that is so unnecessary to adequately and properly tow an Airstream.

Even a Manufacturer, such as Reese, who publishes a "chart' are wrong.

They say I should use a 1700 hitch to tow a 31 foot Airstream. WOW.

How ridiculus, since I tow with a Petrbuilt truck. They say the tow vehicle doesn't matter. How corny. I just proved that it matter.

A few members of this Forums have very recently, downgraded the rating of the hitch bars, that all hitch manufacturers disagree with.

But, not a single person has come back after changing and said, "IT'S WORSE". They have all said "MUCH BETTER".

I did research many years ago as to what causes loss of control accidents, and proved them in over 1000 (one thousand) cases.

Unfortunately, most travel trailer owners don't have a clue as to what is "proper and safe" hitch rigging.

For that matter, RV sales people, probably 98 percent of the time, don't have a clue either.

Most RV shops don't have clues either.

With all those people out there, that should know, but don't know, it's a wonderment as to why more people don't get kiiled, listening to theory and opinions.

Facts is what this is about. I have stated it before, many times over. Those that listened and changed, are now the "true in the hitching know, happy campers."

Those that have changed also now, after the fact, are no longer a "white knuckle" tower.

Please do some physical research before you hog wash the formulas and first hand experiences, as reported by many
owners.

This subject can be kicked around just like the Marathon tires.

I, frankly, will no longer get into this discussion, with anyone that states an opinion, instead of researched facts.

The average Airstreamer, wants help provided by facts, not opinions or theory's.

Opinions are just that, with no fact or foundation.

Andy

[mustang]

I think you are going to have a hard time because of the weight from the Deisel engine. If it is level I would roll with it. I have also read with l3/4 ton and 1 ton trucks go with lighter torsion bars. suspension is heavy duty and they say an Airstream like a soft ride. I like more weight on my drive tires, thats just me but my unit is level

[2airishuman]

Originally Posted by dpandorf

I think the proper procedure starts...

that does make good sense from the procedural side and will get most folks close.

the problem is understand what's happening to the load distribution, or guessing about loads without measuring them.

many 4get that 1000 lbs at the ball is 1200-1500 lbs at the rear axle (depending on overhand/lever length) withOUT w/d...

to understand the what's happening side and the math issues, nicks thread is a great start.

http://www.airforums.com/forums/f464...sis-19236.html

but alot of eyes glaze and d'brains don't make it through to the whole story.

so weighing helps, as you have done, except for truck baselines.

these 250s are listed at 7500 or so curb weights, with a front more front bias for the diesel version.

as i recall my truck is about 83-8,500 loaded (i've got the scale tickets to post),

which brings it VERY CLOSE to the 10k rating when hitched up.

my w/d goal (apart from the levelness issues) is restore original front axle loads,

then evaluate the drive dynamics and make further tweaks based on that and more weighing.

getting to 50/50 on the tv axles gives the best steering feel 4me.

every few 100 lbs rear bias lightens the steering some and increases flex at the junction...

as an experiment i towed 3500 miles with almost NO w/d bar tension...

while the steering was very light, i adapted in a few 100 miles, but the truck needed more steering in put routinely.

and i didn't like the feel in the mountains or on long fast descents or on wet roads with the lighter front end.

the big deal was tire wear, about 4/32nds MORE wear happened on the drive tires in just 3500 miles.

so now my goal is about 500 lbs more on the drive tires, once the trailer is level and the steer axle is back to baseline.

there are LOTS of right answers to the issue. math, weighing and historical myths get us there.

cheers
2air'

[Inland RV Center, In]

Originally Posted by dpandorf

Do you think its possible I may have my springs too tight? My F250 has a GCWR of 10,000 pounds.

My current setup has these results:

Front Axle 5240 lbs, Rear Axle 5200 lbs and the trailer 7540 lbs.

I have a 2000 Classic with a GVWR of 9800 lbs.

My trailer is level after adjusting the W/D and getting these weights.

Your rig has a near as perfect weigh distribution setup.

The other question is what rating hitch bars?

You can accomplish your results using super heavy duty bars and light bars.

The difference, is the amount of road shock that you will transfer to the trailer.

Heavy bars, in a case like yours, gets great results, but cna cause the trailer to get beaten to death, because of a rough ride.

Using softer bars, will still transfer the weights properly, as long as they are adjusted correctly, but they will greatly reduce the road shock that goes thru the TV suspension and into the trailer.

An ideal test, is to have the weight distributed as you have, "AND" while boucing up and down on the coupler, you cause the coupler to move vertically 2 to 3 inches.

With that setup, the weight will be properly distributed, and the road shock will not harm the trailer.

There is far more to consider with a weight distributing hitch, other that what it's name implies.

Ask those that changed for the better.

Andy

[dpandorf]

Originally Posted by 2airishuman

...

the big deal was tire wear, about 4/32nds MORE wear happened on the drive tires in just 3500 miles.

so now my goal is about 500 lbs more on the drive tires, once the trailer is level and the steer axle is back to baseline.

there are LOTS of right answers to the issue. math, weighing and historical myths get us there.

cheers
2air'

Well I may reduce some of my tension see how that "feels" until I can weight it again.

Currently in West Palm working, left the family at Yellowstone's Edge Campground and will fly back there on Wednesday.

www.mtrv.com

check out their live webcam and you can see us parked in the north quadrant.

Here's a shot she just sent me:

[dpandorf]

Originally Posted by Inland RV Center, In

Your rig has a near as perfect weigh distribution setup.

The other question is what rating hitch bars?

You can accomplish your results using super heavy duty bars and light bars.

The difference, is the amount of road shock that you will transfer to the trailer.

Heavy bars, in a case like yours, gets great results, but cna cause the trailer to get beaten to death, because of a rough ride.

Using softer bars, will still transfer the weights properly, as long as they are adjusted correctly, but they will greatly reduce the road shock that goes thru the TV suspension and into the trailer.

An ideal test, is to have the weight distributed as you have, "AND" while boucing up and down on the coupler, you cause the coupler to move vertically 2 to 3 inches.

With that setup, the weight will be properly distributed, and the road shock will not harm the trailer.

There is far more to consider with a weight distributing hitch, other that what it's name implies.

Ask those that changed for the better.

Andy

Thanks for your input Andy, I'll check that when I get back to the campground.

Plus I received the new skylight and will install it when I get back. But as you can see from my photo the mountains got a little dusting today.