tongue weight

[vc]

I have to ask you all on figuring out tongue weight. Weighed my truck and boat together and have separate axle weights for truck. Then I weighed the truck by itself again getting weights for each axle. Can I subtract the rear axle weight of truck by itself from the rear axle weight with boat hooked up to get an accurate tongue weight or not? Thanks

vc

 

[Joe G.]

Weigh the truck. Then hook up the trailer and weigh the truck again with the trailer wheels off the scales. The difference between the truck alone weight and the weight of the truck with the trailer attached is the tongue weight. This allows for things like a weight distributing hitch. I think that weighing individual axles would confuse the issue in many cases.

 

[roadranger]

Originally posted by vc

Can I subtract the rear axle weight of truck by itself from the rear axle weight with boat hooked up to get an accurate tongue weight or not?

vc

Yes.



Remember, the receiver hitch on the back of the truck is only good for 500 lbs. tongue weight. (dead weight)



It increases to 5000 lbs tongue weight if you use an equalizing hitch.

 

[RustyJC]

Actually, the factory receiver is good for 500 lbs tongue weight/5000 lbs towed weight without a weight distributing hitch.



It's good for 1000 lbs tongue weight/10000 lbs towed weight with a weight distributing hitch.



Rusty

 

[Loren]

VC,



No, you can't just subtract the rear axle weight of the truck alone from the same weight with the trailer hooked up to get the tongue weight. The subject is much more complicated than that.



What Joe says to do will work as long as you are not using an equalizing hitch.



Are you using an equalizer hitch? If so, then you should determine the tongue weight of the trailer by unhitching the trailer with only the front jack on the scale. Determine the weight on the front jack with the trailer sitting level. This will be very close (but not exactly) to your hitch weight.



This is because the jack is behind the hitch ball and so it will carry a bit more weight than the ball will. To picture the effect, imagine a jack mounted way back by the axles and you can see how it would carry more weight the farther back it's attached.



The easiest way to determine hitch weight involves two steps. First, weigh the entire trailer alone. Next, hook up to the trailer but DO NOT use your equalizing hitch bars. Just attach the trailer to the ball and nothing else. Your truck will sit lower in the rear.



Pull the trailer onto the scale and weigh the trailer axles only. The difference between the total trailer weight and the trailer axle weight WITHOUT the equalizing hitch is your tongue weight. (Even this is not EXACTLY correct because the trailer is not sitting level. It will be within a few pounds of the right number. )



Now, having said all that, you should know that the only reason for discussing hitch weight is because it is a measure of how far your trailer's center of gravity (CG) is ahead of the trailer axles. This distance affects the stability of the trailer. If the CG is too close to the axles, the trailer will sway from side to side with the slightest input.



Hitch weight, per se, is not necessary to either your truck or trailer. It's a result of a forward CG. The forward CG is required for trailer stability.



The bottom line is, if your trailer is towing well, with no swaying, then you have enough tongue weight. If you are experiencing sway, then the most probable cause is that you don't have enough tongue weight. Adjust as necessary.



As an aside, you should know that a properly adjusted equalizing hitch will add weight to your truck's front axle and reduce weight from your truck's rear axle compared to a hitch without equalizing capabilities. The hitch will also increase the load carried by the trailer's axles compared to the weight the axles carry when the trailer is not hitched up. This is a good reason to ensure that your trailer axles are rated to carry the full load of the trailer by themselves.



Some manufacturers will use a 6000 pound axle on a 6500 pound (rated) trailer, reasoning that the hitch will carry the additional 500 pounds. That's faulty engineering, because an equalizing hitch will send a good portion of that 500 pounds back to the trailer axle.



I know this was long, but the subject is not nearly as simple as it first seems. There are some complicated weight transfers that take place across a trailer hitch.



Happy towing.



Loren

 

[Blu-meanie]

I use a weight scale from Camping World Item #12638. No guessing, no problems.

 

[Joe G.]

Loren,



Isn't the effective tongue weight the weight that the trailer puts on the truck? Maybe that should be called net tongue weight. That's why I recommend the method I do. If I just wanted the tongue weight of the trailer with no effect from the towing vehicle and hitch system I would just weigh the trailer tongue without hooking up to anything.

 

[DBoyd]

Hey Blu-meanie

I have a Camping World weight scale also and was weighing the tongue on the trailer preparing for a trip. I had the unit in the house where it was 78 to 80 degrees and took it out to weigh the trailer in the driveway where it was close to 100 deg. Anyway, the weight started at 650# then after about 30 min. the weight creeped up to almost 900#. Is there something wrong with this scale or was it just the temp differential??

Thanks for the help.

 

[bombero]

I some times get sway if my fresh water tank is completely full. Its in rear of the trailer. My question is if I release some tension on the equalizing hitch will that stop some of the swaying. It will put more wight on the hitch which should help

 

[Blu-meanie]

Maybe you didn't have it level and it had the piston in a bind. After a little warming, it settled to give you an accurate weight. Did you ever try it again?

Mine pretty much reads the same every time: 1000 lbs (gasp!).

 

[DBoyd]

Thanks for the reply. Yes, I relieved the weight off the scale then put it back on and the scale read the same again. It was the first time I used it so it may just be tight yet. Seems to be a fine piece of machine work for such a low price!!! Just hope it is correct!!! There is a way of weighing trailer tongues using a bathroom scale and fulcrums and a little math but the method needs drawings to fully explain. A little hard to do here.

 

[vc]

thanks for all replies guys.

I'll have to get back to the scales next week and do some reweighing. One thing I redid relative to the first post on this topic, I noticed that not only did the rear axle weight increase but the front axle decreased when I weighed the whole rig together. So by taking the difference in weights of with/without the trailer attached on the rear axle, then adjusting the weight by what the front axle was changed, it came out close to what the bathroom scale/folcrum method showed. I think they were within 10 lbs of each other doing this. So would you consider this method ok to use then? On that scale that camping world sells, I think I might get one for quick checks to adjustments at the boat ramp. I will be moving the axles back 18" to where the manufacturer has predrilled frame. Then I will readjust the boat and will need to check tongue weights again. With that tongue jack I can do it quick right at the ramp area and readjust as necessary.

As far as my hitch goes, I got rid of the factory one for a Hidden Hitch that is rated for 1000lbs tongue weight/ 10,000 lbs trailer weight when in the weight carrying mode which is what I am using. It's rated higher in weight dist. mode.

Thanks.

vc

 

[richardleonard]

easy tongue weight see link

Hey All,, see this link - here is an easy way to determine tongue weight. . or at least up to 300 Lbs with a bathroom scale - if you have a higher capacity scale - you could go heaver.



http://www.hitchsupply.com/generic.html;$sessionid$QK0HORQAAAGN0P5MFMOETIR53QVSNPX0?pid=24

 

[Loren]

Joe,



You and I are talking about apples and oranges. The driver needs to get the tongue weight of the trailer (your method will work without an equalizer hitch) in order to determine that the CG of the trailer is far enough ahead of the axles to provide stability.



As long as the CG is satisfactory, with about 15% of the trailer's weight on the hitch, then an equalizing hitch will spread that hitch weight around. Compared to being hitched up without the equalizing feature, an equalizing hitch will increase the weight carried by the truck's front axle and the trailer axles, and decrease the weight carried by the truck's rear axle. With an equalizing hitch, the truck doesn't wind up carrying the full hitch weight because some of that weight is transferred back to the trailer axles.



In other words, the tongue weight of the trailer is not the effective weight that the trailer puts on the truck, as long as an equalizing hitch is used. Without an equalizing hitch, you are correct, the hitch weight is entirely carried by the truck.



Without an equalizing hitch, the rear axle of the truck will carry more than the hitch weight, and the front axle load will decrease by a little bit. Note VC's last post.



Bombero,



Adjusting the equalizing hitch to provide greater weight on the truck's trailer hitch ball will not move the CG of the trailer forward. It will merely redistribute the weight that is already there.



Your problem is not that the truck is not carrying enough weight, but rather that your trailer CG is too far back (close to the axles) to provide sufficient stability. You won't solve your problem by adjusting the equalizing hitch. You need to adjust the load on the trailer to move the CG forward to get the stability you need to avoid sway.



VC,



If your weights using both methods were within 10 pounds of each other, congratulations. That's better than I've been able to do. I consider Joe's method of determining hitch weight the easiest. Weigh the truck empty, then weigh just the truck axles with the trailer hitched up (no equalizing hitch allowed). The difference is the hitch weight. Weighing the force on the jack is pretty close to hitch weight, as long as the jack isn't too far back, as it is on gooseneck and fifth-wheel trailers.



You certainly can use the numbers you got as the hitch weight.



Happy towing,



Loren