Determine tongue weight

[Eric_Phillips]

How do you determine the amount of tongue weight when you load your trailer? When I drive my tractor up on to the trailer the back end squats down and it raises the back end of the truck. As I move forward you can feel the trailer settle back down the the back of the truck lower. I am pretty sure I get the tractor forward enough to have some tongue weight but I have no idea how close it is to the 10-15% mark.

 

[sdkubota]

I would stand on the trailer tounge unloaded and measure from the ground to the bumper. Load your tractor until it measures the same and you have whatever you weigh in addition to the trailer weight. Not perfect but gets you in the ballpark.

 

[Reg]

How do you determine the amount of tongue weight when you load your trailer? When I drive my tractor up on to the trailer the back end squats down and it raises the back end of the truck. As I move forward you can feel the trailer settle back down the the back of the truck lower. I am pretty sure I get the tractor forward enough to have some tongue weight but I have no idea how close it is to the 10-15% mark.

There is a method using bathroom scales and a few short lengths of black pipe(or similar).
(requires understanding of levers, etc.)
Basically you rig it so that the scales see 1/2, 1/3, 1/4 or some other appropriate fraction to make the tongue load fall within the scale's range, then multiply it up.
Personally I think it is dangerous as all heck unless you arrange it so the pipes are parallel to the center-line of the trailer.
I wouldn't try for EXACTLY 1/2, 1/3 or 1/4.
Instead I would aim for something close, then measure and use whatever fraction I happened to get;
say 19/63 or whatever other odd fraction happened.
Messing with pipe rollers carrying several hundred pounds ? - - not with MY delicate little fingers (-:

 

[grnspot110]

Don't try to make a big deal of it!

If your tow vehicle is substantial enough, a small amount of "squat" is OK, but not a lot. Personally, I prefer a longer tongued trailer with wheels farther back than most, giving me more tongue weight than recommended. The main thing is to have a tow vehicle capable of handling the load! ~~ grnspot

 

[sdkubota]

The trailer should be carrying almost all of the weight it is hauling. The reason you want a small amount of tongue weight is to make certain the CG is forward of the trailers balance point. If the center of load is behind the trailer axles (balance point or center of gravity)...it can be extremely unstable pulling down the road.

 

[newbury]

The trailer should be carrying almost all of the weight it is hauling. The reason you want a small amount of tongue weight is to make certain the CG is forward of the trailers balance point. If the center of load is behind the trailer axles (balance point or center of gravity)...it can be extremely unstable pulling down the road.

No, you want 10% at least and up to 15% to keep it firmly on the ball.

For instance my trailer weighs about 2,000 lbs. My B7610 tractor with associated equipment (FEL, Backhoe, chains, fuel etc.) probably adds 3,000 lbs so I try to get 500 to 750 lbs on the ball. For a VERY imprecise method of measuring I got myself and my son on the tailgate (about 450lbs at the time) and saw how far it dipped.

Etrailer has an article on the better ways to do it:
Determining Trailer Tongue Weight | etrailer.com

 

[sawtooth]

No, you want 10% at least and up to 15% to keep it firmly on the ball.

For instance my trailer weighs about 2,000 lbs. My B7610 tractor with associated equipment (FEL, Backhoe, chains, fuel etc.) probably adds 3,000 lbs so I try to get 500 to 750 lbs on the ball. For a VERY imprecise method of measuring I got myself and my son on the tailgate (about 450lbs at the time) and saw how far it dipped.

Etrailer has an article on the better ways to do it:
Determining Trailer Tongue Weight | etrailer.com

This is right. It needs to be 10-15% of total trailer weight so some of the previous post are not reflective of all load / weight requirements. For example i haul 13k which equates to at least 1300lbs on the hitch at all times. However with my truck closer to 15% tows better which equates to near 2000lbs. If i were to stand on the hitch and measure before and after loading the trailer this method would get me no where close to where i need to be. Not stepping on anyones thoughts but want to make sure everyone is towing safely. It really depends on just how much weight your towing. My F250 squats a good 3-4 inches with 2000lbs on the *** end.

 

[tcartwri]

I just roll the equipment forward until the truck levels out.

 

[JCByrd24]

Need to know the tow vehicle and the approximate trailer weight or at least type of trailer and what you are hauling. F350 towing a 5x10 single axle utility trailer, doesn't much matter, squat of the truck isn't going to tell you squat. You shouldn't be able to lift the tongue off the ball, or you could just put the load all the way forward. Tacoma or half ton pulling a dual axle trailer, much touchier subject, equal squat of two dudes in the bed is probably about right, much more and you are likely over the hitch tongue rating, unless you have a weight distributing hitch. Same goes for GM 3/4 ton trucks with factory hitches. A little more information will help us help you.

 

[Reg]

No, you want 10% at least and up to 15% to keep it firmly on the ball.

For instance my trailer weighs about 2,000 lbs. My B7610 tractor with associated equipment (FEL, Backhoe, chains, fuel etc.) probably adds 3,000 lbs so I try to get 500 to 750 lbs on the ball. For a VERY imprecise method of measuring I got myself and my son on the tailgate (about 450lbs at the time) and saw how far it dipped.

Etrailer has an article on the better ways to do it:
Determining Trailer Tongue Weight | etrailer.com

Nope - He has it RIGHT.
The location of the center of mass of the loaded trailer is what MATTERS, tongue load per se does NOT.
Think of a single axle trailer as a triangular platform with support at each apex.
With zero or close to zero load on the tongue the load is "balanced" over the axle and is very unstable - it is teeter-tottered.
This can (is LIKELY TO) lead to sway.
Tongue load is merely a representation of where the center of mass is relative to the axle and the coupler.
(beams and levers, etc.)

 

[newbury]

Need to know the tow vehicle and the approximate trailer weight or at least type of trailer and what you are hauling. F350 towing a 5x10 single axle utility trailer, doesn't much matter, squat of the truck isn't going to tell you squat. <snip>

In my sig is the trailer I use, an 18' Hudson equipment trailer rated at 12,000 lbs. I haven't loaded it down yet, but when I get to Mississippi I plan on using it to move logs and much heavier tractors.

<snip>two dudes in the bed <snip>

Hey no need to talk about that type of stuff!!

Since the OP didn't tell us much about his tractor or trailer I used the lower end example for us sitting on the tailgate. I have set up the "bathroom scale" measurement and I don't think you really need 2 pipes (which tend to roll) but could use two short lengths of half-round molding or even 1"x1" pieces of wood.

 

[meburdick]

One way you can determine tongue weight is with a Sureline scale.

A second way is to estimate it based on "known quantities"... Open the gate of your truck and stack weight on it. Load it up to specific known amounts (300,400,500,600, etc) and then very carefully measure the distance from the ground to a specific point on the hitch at these different amounts.

When you load the trailer, measure again... Use your "chart" from your known weight quantities to determine what tongue weight you are currently at.

SIDE NOTE: You should NOT be loading your trailer and having it lift the rear of your truck. Get jack stands to put under the rear of the trailer or something to support it. If you have fold-down ramps, those often have "feet" that hang down - block those with some large wooden blocks. Your truck was not designed to be "jacked up" by the hitch as it's putting negative tongue weight on the vehicle of somewhere around 1,000 pounds minimum.

 

[sdkubota]

I believe the 10% tongue weight myth is due to campers and such where shifting the weight is not an option. If you load your tongue weight too high on the towing vehicle, you will risk shifting the center of gravity to far back on said vehicle. If that happens you will have an extremely unstable situation and probably roll into the ditch or worse. Hauling equipment allows you to shift the CG on the trailer and all you need is to make sure the CG is in front of the axles at all times. You can carry the weight where ever you want.

 

[meburdick]

I believe the 10% tongue weight myth is due to campers and such where shifting the weight is not an option. If you load your tongue weight too high on the towing vehicle, you will risk shifting the center of gravity to far back on said vehicle. If that happens you will have an extremely unstable situation and probably roll into the ditch or worse. Hauling equipment allows you to shift the CG on the trailer and all you need is to make sure the CG is in front of the axles at all times. You can carry the weight where ever you want.

"Myth"? Why is it a myth?

You actually NEED tongue weight on the tow vehicle for a variety of reasons, all of which have to do with safety (keeping enough traction under the rear wheels for acceleration and braking, keeping the overall distribution of weight between the tow vehicle and trailer at appropriate proportions, ensuring that the tongue of the trailer will never "lift" the rear of the vehicle, etc). If don't have enough (which could be defined as any value less than 10% of the GTWR, including negative tongue weight), you are not towing with optimum overall safety. The heavier the GTWR, the more downward force on the rear axle you need to ensure you have enough traction on the back of the tow vehicle.

Conversely, if you have too much tongue weight, you could break a rear spring / shock, pull the hitch off of the vehicle and/or bend the frame, cantilever the front of the tow vehicle into the air resulting in too little traction to steer and brake (remember that much more than 50% of your braking comes from the front of any vehicle), and so on.

It's physics and math, not a myth.

 

[schmism]

yep it works.

 

[meburdick]

yep it works.

I would imagine that there's some sort of calculation you have to do that takes into consideration the length of the wooden beam and such... yes? And, how will you be able to leverage that getup to measure "actual" tongue weight with it loaded? I have to do something similar at some point so I can understand what sort of tongue weight I'm getting (mostly because I want to try and get the TW to about 900-1000 lbs and then measure the squat of the truck).

 

[newbury]

yep it works.

Does it actually require a yellow jack on the left and a red jack on the right?
I've only got red jacks.

 

[meburdick]

Does it actually require a yellow jack on the left and a red jack on the right?
I've only got red jacks.

You can use all red, just adjust the math accordingly.

 

[schmism]

I would imagine that there's some sort of calculation you have to do that takes into consideration the length of the wooden beam and such... yes? And, how will you be able to leverage that getup to measure "actual" tongue weight with it loaded?

yes that is why there is a tape measure in on the ground....

1 foot to the jack on the right, 2 feet to the jack on the left. mulitiply the reading on the bathroom scale by 3 to get actual tongue weight. (if you use equal dimentions ie 1 foot right 1 foot right, then you mulitply by 2 but for 800-900lbs tongue weight your bathroom scale doesnt go to 400 lbs so your SOL have to use x3)

as to how to do it loaded. it is loaded (see my tractor in on the trailer in the background)

process for me was...
drive tractor on to trailer with it hooked up to the tow vehical.
place a jack under the rear of the trailer (light pressure on trailer)
block trailer wheels
use tongue jack to raise trailer off of ball
pull tow vehical forward to make room
lower tongue jack till trailer is level (seriously use a builders lvl its important)
lower jack at under rear to the point its showing 1/2" air gap (leave in place for safety)
double check level of trailer
set height of jack stands and 2x4 so that it will carry load at tongue-level-dimention
jack tongue up a few inches, move setup under tongue... lower back down
with trailer wheels blocked i can move the tractor slightly on the trailer to adjust tongue weight reading scale directly.
mark location of tractor on trailer

back tow vehical up, hook up trailer and adjust my WDH so that height of the tongue sits level and i have the right "squat" on the rear of my tow vehical (see setting up a WDH online youtube vids)

this gives me a calibrated setup to measure other loads against.

 

[schmism]

Tongue weight is not some mythical number sprinkled with fairy dust. it is an actual REAL number that needs to be paid attention to. not enough you get trailer sway which can lead to out of control conditions extreamly quickly (see youtube), to much you get porpoising and risk breaking/bending/damageing things that arnt easly fixed on the side of the road.