Trailer Balance and tongue weight

[Gerdo]

With the wealth of brains on this forum I know I'll get an answer.

Not a TD but an ATV hauler.

It is a flat bed that is 15'9" long with a tongue length of 4'9". The single axle is 8'7" from the front of the bed and 7'9" from the rear.

If I put my 1500# Polaris Ranger 6x6 (almost perfectly balanced 50/50 F-R) all the way to the front of the bed that will put 1290# in front of the axle and 210# behind. I would also need to put a 4'x 6' (sideways), 600# ATV trailer on the tail of the flat bed trailer. If this ATV trailer is 9" from the ATV and is 12" from the tail of the Flatbed. That would be 810# behind the axle. Both items have a weight of 150#/foot but the rear of the flatbed would have about 1'9" of empty space.

My question is... How much tongue weight will I have?

Is it as simple as... weight in front of axle - weight behind axle = tongue weight? (1290-810=480)

It is an Aluminum trailer so the tongue doesn't weigh much.

[Alphacarina]

Is it as simple as... weight in front of axle - weight behind axle = tongue weight? (1290-810=480)

Not quite that simple

The weight is multiplied by the distance it is behind or in front of the axle. A hundred pounds one foot in back of the axle is the same as 20 pounds 5 feet behind the axle

To figure it out mathematically would be very difficult as you would also need to know where the mass of each machine is located . . . . how much weight do they have on each of their 4 wheels and exactly where in relation to the trailer axle is each wheel located

Don

[G-force]

What does the trailer weight? What is the load capacity of the axle? Just pulling some numbers out of my "you know what", My swag is 500 pounds on the ball. I'm assuming the trailer is around 900 pounds, the atv trailer center of mass is around 70" from the rear, the Polaris center of mass is around 150" from the rear, and the trailer is starting out with around 50 pounds on the ball empty.

[bobhenry]

Then add in the towing height. Are you towing level or nose down. Please don't say nose high this leads to horrible handling and ride problems. Looks like its time to load up and drag out the scales. Thats the easiest way.

[Alphacarina]

What does the trailer weight? What is the load capacity of the axle?

Those don't matter at all so far as computing tongue weight is concerned - The trailer could weigh 5 tons and still be balanced so as to have zero tongue weight before he puts anything on it

Don

[Gerdo]

First, I don't own the trailer yet. The trailer weighs 660#. I know it does have tongue weight when empty but I don't know how much.

The ATV could be balanced in it's dead center.

The ATV is 6' tall to the top of the rollcage but the main mass (engine/trans) has a height of 30".

Lets assume the trailer will be towed level.

I don't want to buy this trailer if I can't get a good balance or enough tongue weight when loaded.

[Gerdo]

I did tow it to Arizona on a 5x10 trailer(it just barely fit). This trailer has the axle in the dead center (bad design). When I drove it on front forward there was very little tongue weight. The same was true when I backed it on. Therefor I can make the assumption that it's CG is pretty much dead center. I had to add a few hundred pounds of sandbags to the nose of the trailer to minimize the sway.

[G-force]

For the weight and balance calcs, your correct. My reason for asking that is most lightweight aluminum ATV trailers I have seen have 2200 pound axles. Unless the one he is looking at has a 3.5k or greater, its going to be overloaded.

What does the trailer weight? What is the load capacity of the axle?

Those don't matter at all so far as computing tongue weight is concerned - The trailer could weigh 5 tons and still be balanced so as to have zero tongue weight before he puts anything on it

Don

[Alphacarina]

I don't want to buy this trailer if I can't get a good balance or enough tongue weight when loaded

Until you load them on there, you can't be certain . . . . but I don't think you'll have any problems because of the 21 inches of 'free space' you have to work with

If your tongue weight is too high, you can put the 600 pound machine all the way to the back and then move the Polaris aft. With the Polaris all the way to the front, you have the ability to move the 600 pound macine fore and aft

You really have a good bit of 'adjustability' to tune the tongue weight to your needs - I don't anticipate a problem . . . . or the need for any sandbags

Don

[brian_bp]

I suggest just putting the numbers into Andrew's Trailer Balance worksheet in the Design Library. The trailer deck is the "main body", and the ATVs are the "extra weights".

As Don said, the balance calculation is a matter of balancing the weight of each component, multiplied by its distance from some reference point. If you assume the middle of each ATV (which is probably close), you've got all of the required numbers.

[Gerdo]

If I'm doing it right it looks like 400-450lbs of tongue weight. Unless I put the trailer on front then I have 80lbs.

[Gerdo]

I just reworked the numbers. It looks like if I put the ATV on first and the trailer on back I will have 10% tongue weight (280#) Even if I have the weight on the front ATV tires (D3), weight on the rear ATV tires (D2), and then the trailer (D1) I get 10.2% (286#).And if I have the trailer in front and the ATV behind then I will have 10.6% on the tongue (297#).

I think it should be good.