How to determine optimal tongue weight

[megaboz]

Most factory trailers have the axles mounted to give the correct 60/40 weight distribution for the correct tounge weight. Its a matter of centering the weight being towed evenly above the axles.

That may be true but not always possible to load the weight accordingly.

Weight distribution hitches are great, but can even be more dangerous if not used properly. Some people should never tow. Many people don't even realize that half of their towing equipment (hitches, balls, receivers, etc ) is not safe for the loads they tow.

While not scientific, I usually measure the drop when I load my trailer at the bumper, or tie a string that just touched the ground to the bumper before I load my trailer. That way I can see that it is loaded.

Air bags really make a difference when towing. It is possible to gain most if not all of your vehicle and trailers proper stance when loaded down.

 

[jejeosborne]

Most factory trailers have the axles mounted to give the correct 60/40 weight distribution for the correct tounge weight. Its a matter of centering the weight being towed evenly above the axles. Sadly most homebuilt trailers dont have the axles centered properly and means you will have to experiment to find the proper weight distribution. Hitch height will effect how well the trailer tows, Hitch to high and you put to much weight on the rear axle. Hitch to low and the trailer will fishtail at highway speeds.

I think you meant to say hitch weight not height. Axle location is important for proper distribution but it is usually done so that empty towing characteristics are favorable. Placing the load over the axles as you describe, puts no weight on the tongue which is bad. 10-15% of the total weight needs to be on the tongue plain and simple. Doing so without scales, not so simple.

 

[jejeosborne]

That may be true but not always possible to load the weight accordingly.

Weight distribution hitches are great, but can even be more dangerous if not used properly. Some people should never tow. Many people don't even realize that half of their towing equipment (hitches, balls, receivers, etc ) is not safe for the loads they tow.

While not scientific, I usually measure the drop when I load my trailer at the bumper, or tie a string that just touched the ground to the bumper before I load my trailer. That way I can see that it is loaded.

Air bags really make a difference when towing. It is possible to gain most if not all of your vehicle and trailers proper stance when loaded down.

Your post sounds like you prefer the use of air bags over the use of weight distribution hitches. Maybe that is not your belief but just wanted to let those new to towing that this is quiet the contrary. Using weight distribution hitches are much safer.

 

[megaboz]

Your post sounds like you prefer the use of air bags over the use of weight distribution hitches. Maybe that is not your belief but just wanted to let those new to towing that this is quiet the contrary. Using weight distribution hitches are much safer.

No, that isn't my point. What I was getting at is that Weight Distributing hitches not set up correctly are more or as dangerous than not having one. It is possible to actually cause the rear of the vehicle to lift off the ground with one, I have seen this happen before. A driver went through a dip in the road, when the rear tires got to the low point and they were suspended in the air. LOL The other point that could be implied is that air bags have more uses than just towing. Everyone should use the proper equipment to get the job done, Weight Distributing Hitch or air bags or whatever it may be.

So moving on, to the OP original question about proper balance, with or without the Weight Distributing hitch (since technically should be connected after the trailer is loaded), most people aren't going to buy a scale, so the next best alternative is to look at the tow rig and trailer for proper balance. In my non-expert opinion, the trailer should be loaded a little front heavy to give the additional tongue weight (estimation at this point) by looking at the sag of the tow vehicle's rear bumper. If the bumper is the same height or higher, then it is to tail heavy, move the load forward. You are going to want the load to be enough so that when you hit a bump the rear of the vehicle isn't lifted. Generally excessive noise coming from the hitch will also be a clear sign that you don't have it properly balanced. I would expect to see the bumper to lower at least an inch to 3 inches. This is going to vary depending on the vehicle (age and size of the vehicle (1/2,3/4 1 ton etc) will make a difference) and the size of the load.

The trailer I use, will drop the rear of my truck about an inch, Weight Distributing hitch when empty is not really advised as they should be setup for when the trailer is loaded as well as inflated air bags should be at minimal inflation when loading the trailer. The air bags lifted the rear back to normal stance in these instances of hauling my empty trailer. The air bags also come in handy when I drop a 1000# in the bed. I don't use Weight Distributing hitches if I am only hauling my little tractor, my truck and trailer is more than capable of hauling lighter loads.

I have hauled 10k on my trailer, and the Weight Distributing hitch alone was not enough to provide a normal stance for both vehicle and trailer. The rear of my truck was still sagging with the load, so I used the air bags to compensate. It was a smooth ride and I never felt safer towing. I agree that Weight Distributing hitches are exceptional devices and should be used, if used properly, otherwise I wouldn't recommend it. But I think that goes without saying for any equipment, if you don't use it correctly it is generally a dangerous piece of equipment.

On a half ton, probably not a bad idea all the way around to use a Weight Distributing hitch. Trucks doing wheelies aren't safe. A Weight Distributing hitch shifts the load more to the front tires of the towing truck. But face it, most people aren't going to spend $500 to $800 for a Weight Distributing Hitch.

My other comments is that I have seen people towing trailers greater than the hitch allows. Not many people think about it, at least I didn't when I first started towing, they see the hitch in Walmart and think they are good to go for any load. When in reality, between the 2000# trailer and a 4000#+ load, they are probably exceeding the capacity of their equipment.

 

[mikehaugen]

just to clarify, weight distributing hitches are not just to raise tha back of the vehicle. I don't use one because I rarely tow beyond 5 or 6k with a 3/4 ton truck, but I understand what they are and how they work, actually I even have the setup just haven't installed the parts onto any of my trailers. Anyway, air bags do no take the place of the WDH. A WDH will actually put leverage back into the truck side hitch frame and spread the weight across the entire mounting point... i.e. all of the bolts. Think of it this way... with the drawbar in the hitch, your loading point is probably roughly 18-24 inches back from the rear mounting bolt of the hitch- that is an incredible amount of torque to transfer through the hitch. This is why HITCHES themselves have different capaicities with a WDH versus without. This is also why I always try to configure different drawbars that keep the load as close to the rear bumper as possible. Air bags on the truck just raise the back of the truck but do nothing to spread the weight out, that is also why they are called weight DISTRIBUTING hitches and not weight eliminating hitches.

 

[mikehaugen]

I also forgot to mention that a WDH will help prevent some of the front axle unloading. Another thing that airbags will not do.

Again I am not knocking air bags, I think they serve a purpose, but they do not take the place a WDH.

 

[megaboz]

I also forgot to mention that a WDH will help prevent some of the front axle unloading. Another thing that airbags will not do.

Actually not 100% accurate, but definitely not as effective as a WDH.

 

[homeputter]

I used a bathroom scale to measure tongue weight at different heights. Google "measure tongue weight" and you get several posts how to rig the scale so a 0-300lb scale can measure 3 or 4 times that weight depending on spacing of supports.
Worked great for me. But, I could just barely get the weight I wanted on the tongue of my 18' trailer. I had a 350lb box blade in front and a BX25 both as far to the front as I could get them. Still only had about 400lb on hitch.

 

[CurlyDave]

That may be true but not always possible to load the weight accordingly.

Weight distribution hitches are great, but can even be more dangerous if not used properly. Some people should never tow. Many people don't even realize that half of their towing equipment (hitches, balls, receivers, etc ) is not safe for the loads they tow.

While not scientific, I usually measure the drop when I load my trailer at the bumper, or tie a string that just touched the ground to the bumper before I load my trailer. That way I can see that it is loaded.

Air bags really make a difference when towing. It is possible to gain most if not all of your vehicle and trailers proper stance when loaded down.

I have used air bags in the past, but after some bad experiences, have started to dislike them and have modified the way I use them. I have a WD hitch I use on all my trailers. Truck was a 2000 F-150.

Bad experience #1:

Inflate air bags to 80 psi (100 is manufacturer's max) and take 6'x12' dump trailer to dump. Load is ~8000 lbs. for both trailer and payload. Almost get there when there is a loud bang and one of the air bags blows out. Blown out bag scrapes against tire causing tire damage. Serious roadside modification of the remains of the bag with a 2' pry bar is required before metal parts of air bag can be moved away from tire to prevent even more tire damage. This is not a fun field modification with traffic whizzing by at 60 mph. Fortunately dump is only 3-4 miles further and I can limp in there and dump the load so I can get home with a much lighter trailer.

Order a new air bag and install same.

Bad experience # 2.

Take toy hauler to deer camp, which is ~120 miles from home. Toy hauler weight is ~6500 lbs. Again inflate air bags to 80 psi. On the trip back home another loud bang, and another bag popped. This time I know exactly what to expect. Fortunately no field modification of blown out air bag is necessary to prevent tire damage, and the only dicey moments are those spent inspecting the air bag. There is no road shoulder here so blocked traffic and the potential for an accident with me under the pickup inspecting the blown air bag is very nerve-racking. The next issue is that I have to limp home 35 miles with a functional air bag on only one side.

These two experiences taught me a lot. The remedy is:

1. Bought a F-250 to haul heavier trailers. This is a good but expensive solution.

2. Kept the old F-150, but now do not inflate air bags above 50 psi. Keep loads in dump trailer lighter when using the F-150.

3. Only use the F-150 for short runs.

I have convinced myself that the issue is the trailer will pitch back and forth after hitting some bumps which a shaped correctly to induce this motion. The bumps which will start the pitching do not have to be particularly large and most of the time do not look enough like trouble to cause me to brake or slow down before hitting them. The pitching movement of the trailer can cause significant dynamic overloads of the tongue weight.

 

[megaboz]

CurlyDave, I have never heard of air bags blowing out. I have see where installations of air bags were just T'd and the air would squeeze from one side to the other. In the event of your trailer pitching (which really shouldn't be happening to the extremes you mentioned) and slight load shifting from left to right (or the other direction) I can see one air bag over inflating. Air bags shouldn't be installed that way. Not sure about your installation.

Now my comments about air bags and WDH is that in the wrong hands a WDH is a dangerous tool to a novice user.

Obviously proper equipment with heavy loads and proper setup of said equipment is imperative.

I use a combination of the two.

People need to take the advice given here with a grain of salt and filter out what applies to them. There is alot of valuable info in this thread.