Weight Distribution - Myth vs Truth

[richard5933]

Originally Posted by Andy543

Actually, no. The recommended FALR is only for use when you are towing heavy trailers that could overload the truck's rear axle. When towing an Airstream that weighs about half the truck's rated load, a WD hitch is not required, nor is it desirable.

This advice goes against the manufacturer's instructions for some tow vehicles, such as mu 3/4-ton Suburban.

With WD the tongue weight limit it 1000 lbs, without only 500 lbs. They specifically recommend using a WD hitch to obtain full towing capacity.

[Andy543]

Originally Posted by richard5933

This advice goes against the manufacturer's instructions for some tow vehicles, such as mu 3/4-ton Suburban.

With WD the tongue weight limit it 1000 lbs, without only 500 lbs. They specifically recommend using a WD hitch to obtain full towing capacity.

Yes. You need WD to make the rated load. Otherwise, you will overload the rear axle. If you're towing half the rated load, you shouldn't use a WD hitch.

[jcl]

Originally Posted by blacklab

I have a 2024 GMC 3500 SRW. The Manual says FALR should be 25%. A GMC engineer who works with these HD trucks says it can be between 25% and 50%, depending on the Trailer, etc.

I believe Ford and RAM have different FALR recommended targets.

Doesn't the recommended FALR really dictate how much weight should be distributed up front?

Cheers,

Bryan

The recommendation for FALR is matched to what the truck manufacturer used when testing the truck per the SAE tow rating standard. That standard is not designed to optimize towing performance. It simply allows the manufacturer to nominate a number, and use it in the test. There is nothing to say it is the best number to use.

Years back, the industry standard was to restore much more load to the front axle. The thinking was, why would you want the front axle any more lightly loaded than it was with no load, as that reduces steerability.

My copy of the SAE J2807 tow standard (2016) lists 100% FALR unless the tow vehicle manufacturer specifies otherwise. I believe they have been through a couple of iterations, and there are likely multiple values from different versions of the standard.

By specifying less FALR, the tow vehicle manufacturers have been able to use less stout receiver hitches. The tow standard has limits for deformation of the hitch from applying WD. Lighter hitches are cheaper, and they save money on every vehicle they manufacture. All they need to do is meet the SAE test standards, which is a very low bar, and if they are able to accomplish that with 25% or 50% FALR, that can be a significant cost savings to them.

Here is an example. RAM specifies different FALR numbers for their 1500 vs their 2500/3500. It seems intuitive that a heavy duty truck (especially one with a heavy diesel engine up front) would call for less FALR than the 1/2 model from the same manufacturer. But if you look at the receivers, the HD truck has a much stronger receiver than the 1/2 ton model. And RAM calls for double the FALR on a 2500/3500 as their 1500 model.

Another example is that the SAE standard specifies 10% tongue weight. A trailer may be more stable with 12%, but the SAE standard is designed to be a standard, not to be the best performing configuration.

Best recommendation is to test your own combination, perhaps starting at 25% and moving up from there. If more FALR provides better handling, then use it, up to the limit of the strength of the receiver. If it deforms, then that is too much for that receiver.

Originally Posted by Andy543

Actually, no. The recommended FALR is only for use when you are towing heavy trailers that could overload the truck's rear axle. When towing an Airstream that weighs about half the truck's rated load, a WD hitch is not required, nor is it desirable.

Actually, no. The tow vehicle manufacturers recommend FALR for any trailer over 5000 lbs in many case (including for your RAM truck). For your HD RAM, it is 50%. If we think about a hypothetical trailer weighing 5000 lbs, which likely has a 500 lb tongue weight, maybe 600 lbs, it is hard to imagine that exceeding the GAWR for the rear axle. And if the WD requirement is only for the rear axle rating, then why would RAM specify a lower FALR (25%) for their 1500 with a much lower rear GAWR than their 2500/3500 models?

You can decide not to follow your tow vehicle manufacturer's recommendations, but that is your call.

[Profxd]

The SAE standard is really just a specific set of conditions to compare tow vehicles of the same class. It does demonstrate a few important general guidelines for consumers.

First adjust loading of the trailer to control sway secondly reduce TW to reduce the impact to the TV and third reduce the need for WDH tension.

[rideair]

After reading four pages of TW percentages, SAE Standards, FALR Recommendations, GAWR, etc.., etc.. not really sure what I should do.

All I did was take my 1962 Ford Galaxie Convertible over to a buddy's place that's an old school welder by trade. We laid up under the backend of the car for a few minutes taking some measurements, cut some square-tube, a little tack-welding of pieces (around a gas tank) fitting everything up to make sure it looked good, double checking mount points to bolt everything on the car after the receiver was welded up on the bench, it fit great! (even put the receiver about 6 inches behind the license plate to keep it tow ball close to the bumper). From there, we took an off the shelf hitch bar, cut as needed, placed the hitch head at the angle that looked like it would distribute the weight correctly based on where the bars laid in reference to the ground/trailer/etc.. and started welding. Added the standard anti-sway bar and the old Galaxie does great going down the road pulling a 1966 Airstream.

Now, I'll be the first to admit that Mr. Ben did graduate from Virginia Tech with an Engineering Degree, started welding at the age of 10 working at his father's iron works business and can build most things before others even finish thinking about it. But we've been pulling trailers behind cars/trucks for a really long time, and we no longer pull with cars that have 5' of trunk hanging behind the rear axle.

I'd suggest everyone read the Andy link and watch the second "Andy" video, you'll learn all you need to know. If a couple of rednecks can do it with nothing more than the knowledge below, I'm sure others can as well, good luck out there!

http://www.airstreamcentral.com/art...ory/Page1.html

https://www.youtube.com/watch?v=JrgCNR6HvRI

[Andy543]

I think the biggest myth about weight distribution hitches is that they are safety devices. They're not. There is a trove of information showing that they make a jackknife accident more likely. Their purpose is not safety, but to allow you to overload your tow vehicle without going over the rear axle load limit, i.e., to make a big tow vehicle out of a small one. Yes, the wd hitch will allow you to tow an oversized trailer, but at what speed? If you're towing across town at 40 mph you'll probably be OK, but if you're on the interstate trying to do the speed limit, your safety will be compromised. When you're going straight, especially if you have a sway control hitch, you'll be lulled into a feeling of security, but if you ever have to make a hard turn to avoid an accident your rig will be much more prone to jackknife.

Try hooking up a 10,000 lb. trailer to the tow ball of a 5000 lb. F-150. The rear will be dragging on the ground and the front will be pointing at the sky. It's an accident waiting to happen. Now, ask yourself if you can make this rig OK by putting a couple of spring bars on it? No, the only way you can fix the problem is to increase the size of your tow vehicle or decrease the size of your trailer.

[richard5933]

Originally Posted by Andy543

I think the biggest myth about weight distribution hitches is that they are safety devices. They're not. There is a trove of information showing that they make a jackknife accident more likely. Their purpose is not safety, but to allow you to overload your tow vehicle without going over the rear axle load limit, i.e., to make a big tow vehicle out of a small one. Yes, the wd hitch will allow you to tow an oversized trailer, but at what speed? If you're towing across town at 40 mph you'll probably be OK, but if you're on the interstate trying to do the speed limit, your safety will be compromised. When you're going straight, especially if you have a sway control hitch, you'll be lulled into a feeling of security, but if you ever have to make a hard turn to avoid an accident your rig will be much more prone to jackknife.

Try hooking up a 10,000 lb. trailer to the tow ball of a 5000 lb. F-150. The rear will be dragging on the ground and the front will be pointing at the sky. It's an accident waiting to happen. Now, ask yourself if you can make this rig OK by putting a couple of spring bars on it? No, the only way you can fix the problem is to increase the size of your tow vehicle or decrease the size of your trailer.

I would say that this post comes under the category of fear mongering. You keep talking about "troves" of information proving your theory, but I just haven't seen you produce it.

If WD hitches were as dangerous as you claim we'd be seeing constant headlines and stories about jackknifed trailers. Yes - there are some, but no where near the numbers that would support your claims.

Where are these troves of data you keep talking about?

[jcl]

Originally Posted by Andy543

I think the biggest myth about weight distribution hitches is that they are safety devices. They're not. There is a trove of information showing that they make a jackknife accident more likely. Their purpose is not safety, but to allow you to overload your tow vehicle without going over the rear axle load limit, i.e., to make a big tow vehicle out of a small one. Yes, the wd hitch will allow you to tow an oversized trailer, but at what speed? If you're towing across town at 40 mph you'll probably be OK, but if you're on the interstate trying to do the speed limit, your safety will be compromised. When you're going straight, especially if you have a sway control hitch, you'll be lulled into a feeling of security, but if you ever have to make a hard turn to avoid an accident your rig will be much more prone to jackknife.

Your unsubstantiated claims about jackknifing and oversteer with WD hitches have been previously addressed (debunked?) here. This thread linked below was a good case study.

https://www.airforums.com/forums/f46...bi-230544.html

Originally Posted by richard5933

I would say that this post comes under the category of fear mongering. You keep talking about "troves" of information proving your theory, but I just haven't seen you produce it.

If WD hitches were as dangerous as you claim we'd be seeing constant headlines and stories about jackknifed trailers. Yes - there are some, but no where near the numbers that would support your claims.

Where are these troves of data you keep talking about?

Andy posted them previously. Unfortunately for him he was hoisted by his own petard.

[Boxite]

Weight Distribution issues are separate from sway issues.

If your rig weighs more than half the GW of your tow vehicle you might need a WDH.

Of if, after hitching-up…you experience rear end sag and front end lift such as the TOP illustration…. You might need a WDH.

But if your trailer does not exceed half your TV GW…and you have the trailer loaded to a tongue wt of 10%…and your rig appears like the Bottom Illustration…. you do not need, nor is it advisable to use a WDH.

If you experience excessive sway …then your trailer is either too long for your TV… or your trailer is loaded improperly (too much rear weght/insufficient tongue wt) …. or you are towing too-fast for the combination…. or all the above. The solution is to correct those matters. An anti-sway device may add stability under certain transient conditions, however.*

I have had excellent results with my 22’ 4K lb Bambi towed by my 1/2 ton Ram 1500 Crew Cab using only the “ball”. A longer/heavier trailer would likely require a heavier TV unless a Band-Aid such as a WDH is used.

* I have added a friction anti-sway only because of momentary sway sometimes induced by passing 18-wheelers on the Interstate.

Only You can determine what makes you comfortable and safe….but the most Important Thing is: Slow Down!

[Boxite]

Originally Posted by rideair

After reading four pages of TW percentages, SAE Standards, FALR Recommendations, GAWR, etc.., etc.. not really sure what I should do.

All I did was take my 1962 Ford Galaxie Convertible over to a buddy's place that's an old school welder by trade. We laid up under the backend of the car for a few minutes taking some measurements, cut some square-tube, a little tack-welding of pieces (around a gas tank) fitting everything up to make sure it looked good, double checking mount points to bolt everything on the car after the receiver was welded up on the bench, it fit great! (even put the receiver about 6 inches behind the license plate to keep it tow ball close to the bumper). From there, we took an off the shelf hitch bar, cut as needed, placed the hitch head at the angle that looked like it would distribute the weight correctly based on where the bars laid in reference to the ground/trailer/etc.. and started welding. Added the standard anti-sway bar and the old Galaxie does great going down the road pulling a 1966 Airstream.

Now, I'll be the first to admit that Mr. Ben did graduate from Virginia Tech with an Engineering Degree, started welding at the age of 10 working at his father's iron works business and can build most things before others even finish thinking about it. But we've been pulling trailers behind cars/trucks for a really long time, and we no longer pull with cars that have 5' of trunk hanging behind the rear axle.

I'd suggest everyone read the Andy link and watch the second "Andy" video, you'll learn all you need to know. If a couple of rednecks can do it with nothing more than the knowledge below, I'm sure others can as well, good luck out there!

http://www.airstreamcentral.com/art...ory/Page1.html

I don’t mean to come-across as to critical or to appear as a know-it-all….(sometimes a difficult task for me)…but there are Three significant errors in that Video. It reminds me of the old adage “ Measure it with a micrometer…mark it with a grease pencil…then cut it with a hatchet.”

1- He makes a big deal about 16ths of an inch differences in fender heights as if that were so important….while adding bolts for fine-tuning chain lengths etc… yet fails to take into consideration his own weight and suspension-change when he and his passengers board the vehicle.

2- He says you “cannot overtighten” the friction anti-sway. That is not true. They can be tightened to the point of splitting the receptacle on the end of the device. I can show one to anyone further interested…I had one fail….it’s still in my garage.

3. He pooh-poohs the belief of others who advise against backing up with the anti-sway applied…stating that it’s perfectly fine to do so. This is Not Correct…. when backing with it connected…and turning while backing…it can easily bend the blade on the device. It’s always Best to Loosen the friction prior to backing.

[Wazbro]

Originally Posted by Boxite

I don’t mean to come-across as to critical or to appear as a know-it-all….(sometimes a difficult task for me)…but there are Three significant errors in that Video. It reminds me of the old adage “ Measure it with a micrometer…mark it with a grease pencil…then cut it with a hatchet.”

1- He makes a big deal about 16ths of an inch differences in fender heights as if that were so important….while adding bolts for fine-tuning chain lengths etc… yet fails to take into consideration his own weight and suspension-change when he and his passengers board the vehicle.

2- He says you “cannot overtighten” the friction anti-sway. That is not true. They can be tightened to the point of splitting the receptacle on the end of the device. I can show one to anyone further interested…I had one fail….it’s still in my garage.

3. He pooh-poohs the belief of others who advise against backing up with the anti-sway applied…stating that it’s perfectly fine to do so. This is Not Correct…. when backing with it connected…and turning while backing…it can easily bend the blade on the device. It’s always Best to Loosen the friction prior to backing.

Hate to be picky but.
1 He did mention needing extra WD tension if the trailer and/or TV were not loaded ready for camping. Maybe more detail would have helped?

2 I suppose he should have said “he cannot overtighten” the friction anti-sway. My guess is 70% of people in the US can't apply enough force to do the damage you're talking about without torque amplifiers like adding a pipe(if it's not defective, damaged or corroded) and that percentage increases significantly as the peoples age goes above 70.

3 Well you can backup without loosening that type of sway control, if you limit how sharp you turn. He did mention you can turn sharper without the sway control.

[dznf0g]

I always backed with the friction control applied with my old 22'sob. Never a problem....if installed at the proper length, and not backing too sharp. I put close.to 100k on that hitch setup and trailer over 17 years.

[Gibson3798]

Originally Posted by NutmegsCamper

That scenario right there is exactly why I have the backup camera always on when towing. I call them "sleepers" and they will decide to pass you in the lane you are turning into after they see you put your turn signal on. They travel so close to the back of your camper that you cannot see them in the tow mirrors. Our Blue Ox Sway Pro saved us in the exact same situation.

Great point, and this is meant to take nothing away from that great advice, but when an idiot is coming up behind you at a high rate of speed, you won't see him until it's too late. That driver is the exception to any method of using common sense and accident prevention.

I've had both motorcycles and cars pass me in excess of 100 mph on the right side as I was contemplating moving over. I watched a video of a daredevil as his helmet cam recorded his assault on the highway between San Diego and somewhere near L.A. as he got up to 145 mph, weaving in and out of cars that had no idea he was anywhere close.

[rideair]

Please note:

The "Andy" video is "Andrew Thomson, Jr" of Can-Am Airstream in Canada. Here's the link to their history page.

https://www.canamrv.ca/our-history/

He is known to be one of the best when it comes to setting up trailers, tow rigs, etc...

Many years of experience in those words of wisdom.

Just Saying,

[emsgr8]

Originally Posted by Tim A.

This generalization doesn't apply to all sway control systems. The sway control of ProPride and Hensley hitches guides the trailer around a turn.

Tim

This is the correct answer and the reason why we are going with the Pro Pride 3P. Yes it’s expensive. But we just spent a lot of money on a new AS and the physics behind the Hensley and Pro Pride make sense to protect us and our AS/TV. Watch this video to understand how these hitches prevent sway.

https://youtu.be/Bidk4Dhkz6U?feature=shared

[Larryi]

When you were at the Bandera Rally, what wdh seemed to be the popular hitch of choice by Vinnie or AS or Shocker? I'm contemplating pairing the WDH and air style hitch. I've used Equalizer before but Blue Ox looks like it could have an advantage of easy chain link adjustment to dial in the amount of tension applied? Thanks

[gypsydad]

Originally Posted by Boxite

I don’t mean to come-across as to critical or to appear as a know-it-all….(sometimes a difficult task for me)…but there are Three significant errors in that Video. It reminds me of the old adage “ Measure it with a micrometer…mark it with a grease pencil…then cut it with a hatchet.”

1- He makes a big deal about 16ths of an inch differences in fender heights as if that were so important….while adding bolts for fine-tuning chain lengths etc… yet fails to take into consideration his own weight and suspension-change when he and his passengers board the vehicle.

2- He says you “cannot overtighten” the friction anti-sway. That is not true. They can be tightened to the point of splitting the receptacle on the end of the device. I can show one to anyone further interested…I had one fail….it’s still in my garage.

3. He pooh-poohs the belief of others who advise against backing up with the anti-sway applied…stating that it’s perfectly fine to do so. This is Not Correct…. when backing with it connected…and turning while backing…it can easily bend the blade on the device. It’s always Best to Loosen the friction prior to backing.

Can we all agree that a "good" WDH with Sway Control bars, when "set up properly" will accomplish a few "good things" while towing. First, it will transfer the "tongue weight" load, back to the tow vehicle front steer axel and the trailer axels. (this helps for a more stable ride and control). Second, when set up properly, your front fender lip, should be same height from pavement, with hitch on the ball as it is without the hitch on the ball, if the WDH is set up properly. (The recommendation is not more than 1/2" difference) Third, the Sway Control bars are meant to help keep the TT in line, preventing sway.

Now, as most of us here know (), there are several different models, each with marketing claims, which tell why their units are the "best" for towing. I have had 3 different models over the past 15 years towing Airstreams, including a "friction" bar I had with my Casita.

All I can say, is the Blue Ox Sway Pro is pretty darned good set up. The tapered bars (spring bars) "move" during "maneuver's" and turns adding more "tension" to pull the TT back in line with the TV. You do not have to remove when backing/nor worry about them "buckeling" like happened to me with square bars on my Equalizer early on with my first Airstream. Also, the "friction" bar some folks use, may be fine for a lighter TT but it also adds "resistance" to your trailer lateral movement....the Blue OX Sway Control, does not have this issue. All these Mfg. of WDH offer sales pitches on why their unit is the "best". Trouble is, not all of "us consumers" are smart enough to know who's is really the best! So, like anything else, you go with your gut and trust and hope everything works out!

I met a guy this past weekend towing a new 25' with his GM 3/4T, who had a new "Shocker" set up with his Blue Ox. He was telling me how much he liked it, but I noticed he had no lubricant on his hitch ball. When I asked where the grease was, he said, "oh, I don't use grease on the ball...no grease adds to the resistance which helps while towing". Really....he said that. I told the Shocker rep who came later to show his new units, and he shook his head and started laughing! My point is, everyone is different....some more than others...

But, that's why I love the Forum...you learn so much, right or wrong!