How to balance load on a dual axle trailer

[gordon21]

I have lots of experience towing various single axle boat/utility trailers up to about #3500 total load. I now need to learn the rules for towing with a 16' open bed landscape trailer with dual axles and one set of electric brakes on the rear axle. My rule in the past has been to have 60-65% of the weight in front of the single axle center line. A tongue weight that is too light is a very dangerous thing. Will that same rule still apply now? I am guessing that too much weight in front could cause the rear axle to not have enough downward pressure to brake effectively. I will be putting a JD 790 with FEL and filled tires on the trailer. The rig is about 13' long and the trailer is 16' Should I run the rig all the way to the front and let the bucket hit the front uprights or leave it further back by a foot or more? I am guessing the total weight of the tractor to be 3800# and the empty trailer about 1450# for a total weight of 5250# and the trailer is rated at 7000#. Do I need to possibly shift 60% of the weight directly over the two axles like a big tractor trailer combo. The thought of an unbalanced load (too light a tongue weight) at 50MPH scares the crap out of me. I have personally seen an accident happen where the boat trailer started swaying and the driver eventually lost control. It was not pretty. The combo jacknifed and skidded off the shoulder. The front 4' of the boat crushed in the back seat area on the side of the pickup. The trailer tongue bent around the rear of the pickup bed. The boat motor was about 3' in front of the front bumper. Imagine a very tight V. Luckily no one got hurt. Thanks to all of your knowledge shared on this forum, the tractor itself will be chained down at all four corners with 5/16" grade 70 chain and ratchet tighteners.

 

[Bird]

Lewis, a negative tongue weight is definitely very dangerous, of course, so yes, it's important to load a 2 axle trailer properly just as it is with a single axle trailer. Obviously weighing everything on certified scales is the best method, but trial and error (oops, trial with no errors) also works. With a 2 axle trailer, I prefer having the bulk of the weight centered right between the axles, but I also want the trailer loaded so that it has at least a little more weight on the tongue than the empty trailer had. I am assuming you are going to pull this trailer with a pickup; half ton, three-quarter, or one ton? When no other means of weighing is available, I'd just measure from the top of the hitch to the ground with no load on the trailer, then I'd measure again after I loaded the tractor, and move the load forward or backward until the weight on the tongue lowered the top of the hitch approximately one inch lower than it was with the empty trailer.

 

[gordon21]

The few times it will be towed in the next 6 months, I will borrow a F250 or F350. All I have now for towing is a jeep Wrangler. Many years ago I bought a boat bigger than my tow vehicle would handle. I was able to get a new full size Bronco out of that boat purchase. I don't know if the wife will see through my "new" need for a new F150 to tow the tractor. Maybe she will not remember the Bronco.....

Thanks for the tip on dropping the hicth 1" when loaded. I would have guessed 2" or more. That's why I ask advice from you guys. Is there anything special about the electric brake setup I should know? What is the purpose of the backup battery pack?

 

[tawilson]

That's a breakaway switch, in case the trailer comes loose it locks up the brakes.

 

[gordon21]

There is a mechanical switch with a wire attached to a plunger. When the plunger gets yanked out, the battery pack powers the brakes???? If that is how it works, that's pretty cool. There was no such backup on the old hydraulic surge brakes I am used to. They only worked when the trailer was attached to the towing vehicle and it braked.

 

[KentT]

Yes, that's how the breakaway switch works...

Plus, electric brakes don't have to have some special provision just so you can back the trailer up, like hydraulic surge brakes do...

 

[tawilson]

It's going way back into the dim recesses of my brain, but I believe I've seen surge brakes with breakaway. A lever with a chain maybe?
A comment on Birds suggestion. I'd recommend measuring front and rear before and after loading and make sure the front drops 1'' more than the rear. I think it's possible the front could drop 1'' but if the rear dropped 2'' you haven't enough or any tongue weight. I could be wrong.

 

[KiotiJohn]

Since I leave the house with different attachments on my tractor, I have to load to a different spot almost every time.

I pull the tractor on while watching the rear end of the Suburban, with tow package, until I see the rear bumper fall between 1-2". The rear tires of my tractor will almost always be right about between the axles.

I take it for a test run, and in just a short distance, I can tell if it's right. I have a spot that I run over that will make the trailer come up on the tonuge as I pass over it. If I don't have it loader right, the rear of the Suburban will bounce up and down a couple of times. I go back home and move the tractor up just a bit. Works great for me.

With the electric brakes, you'll have a control switch on each side usually. One is to time it with the forward stopping motion of the tow vehicle, and the other adjusts the amount of braking. When the trailer is empty, you turn down the amount of baking or it will snatch you're head off! Turn it back up when loaded. The best way to test it if it's like mine, it has a manual slide on the front of the brake controller which you can slide over until the brakes on the trailer engage. You want them to start stopping you, but not lock. Don't hit the tow vehicle's brakes during this test. When it brings you to a slow stop without jerking you, you can then try it with using the tow brakes as well. It takes a bit of experimentation to get it right, but it's not difficult.
Make sure you run the electric back up cable through something on your hitch so that if it comes loose, it will pull the plunger in the battery box. I run mine through a hole next to the Reese hitch and back to a clip on the trailer, so the cable is not hanging down in the road.
Sorry this is so long, and I hope it is of some use.
John
EDIT: My brother's surge braked trailer has a chain that runs to a lever that is pulled, forward I believe, if the trailer gets loose.
J

 

[Bird]

Lewis, one reason I said approximately an inch is because I didn't know what you'd be towing it with. If the tongue weight drops the hitch one inch on a one ton truck, you've probably got plenty of tongue weight. With a lighter duty vehicle, 2" might be more appropriate. Of course you don't want enough tongue weight to lighten the front end of the truck enough to affect the steering. And tawilson's suggestion to measure both front and rear of the trailer is a good idea, too. Ideally the trailer should be sitting level both empty and loaded.

 

[Joe1]

There were several threads a few weeks ago about having brakes on ALL trailer wheels. If you have not purchased the traielr, you should be able to get 4 wheel brakes for only a few hundred more. If you already have it, adding brakes should not run more than $300.00. This is particularly important if the truck towing the load is marginally near or at its rated towing capacity as a mid-sized pickup would be.

Heavy enough for four tires, heavy enough for four brakes.

 

[jcmseven]

Gordon,

When I was hauling my JD 4520, on a trailer that weighed itself over 2500# I backed the tractor on. Even with a 4n1 bucket on the front, the tractor with loaded tires was rear end heavy. I could not pull it for enough forwards to prevent it from unloading the rear of the truck. I made the mistake once, and stopped after about two miles to reverse the tractor. It made a big difference. Some RV pullers and long distance pullers use the load sensing hitches. I never have used one, but I have heard they work nicely. Your tractor is not that heavy, but it is heavy enough to steer itself on your trailer. I would try backing it on first, see if that helps a bit. It might make your ride more stable without you having to pull the tractor all the way to the front of the trailer.

John M

 

[tawilson]

It may be cheaper in the long run to get the 4 wheel brakes. You have to do a lot of trailering to wear out the brakes on a trailer, but it wouldn't take long to wear out the brakes on your tow vehicle if it has to do more of the braking.

 

[Hooked_on_HP]

You should also consider a weight distribution hitch. It has two arms that go from the trailer to the receiver on the truck. It distributes the weight evenly on the truck not just on the back end. It also helps prevent sway and makes the ride smother.

 

[rdln]

If the trailer has leaf springs, there is an equlaizer bracket connecting the front spring to the back spring. I watch this equalizer pivot towards the truck, this tells me there is more weight on the front trailer axle. I cant tell how much it should pivot its just an eyeball thing. If I had to give a number I would say 10 - 20 degrees from the unloaded but connected to the truck position.

 

[bncsauve]

I have usually seen recomendations for 10-15 percent of the trailer weight on the tongue. In your case, that would be 525 - 785 lbs on the tongue. I saw one post where the thought was to start loading bags of material on your tail gate until you had the right weight and then measure the distance to the ground. Un load it and measure again. This would be the correct deflection when you had the proper tongue weight.

 

[Highbeam]

The tandem axle trailer is not two separate independent axles. They share a goofy center suspension support to allow the axles to evenly carry the load between them even if the tongue is high or low. It is amazing to go over speed bumps since the trailer stays level and the axles articulate over the hump. Regardless, both brakes having axles is superior.

My trailer, a 10,000 lb rated car hauler type bumper pull trailer had directions for loading. The axles are set at a particular location such that an even application of cargo across the trailer deck would give the ideal 10-15% tongue weight. Empty, the trailer weighs 2500 lbs with 250 of that as tongue weight. Pretty good. Too bad I don't know the center of gravity of the tractor or I would center that over the centerline of the deck, instead I try and center the load on the trailer to start and be sure that there is a good settlement of the ball.

To fine tune I go to a closed weigh station on the highway. These are most often closed but they leave the scales on and visible for people like me. Loaded with my 4500 lb tractor I have a 7000 lb trailer so shoot for just over 700 lbs on the tongue. Then take a marker and mark the trailer deck with the location of the bucket lip or something else that will make it easy next time.

I also adjust my hitch head to be sure that the trailer rides level just so that the ball is in the center of its operating range, butt is not dragging, and to keep everything looking right.

I am a big believer in the weight distributing hitch and the hitch has a setup procedure too that involves the weigh station so I spend a good bit of time there adjusting things. Once everything is set right, just use it.

 

[gordon21]

Your rig looks to be the same approx size as mine. The rear tires are centered directly between the trailer axles. Does that match up with everyone else who has replied and helped me? JD 790 which is the same physical size as almost everyone elses 28-32HP on a 16' trailer. The back 3' of the tractor has all the weight of the tires, rims, fluid, fenders, seat and the rear end gears. I assume all that weighs 1500# in just the last 3'. If so, then almost half the entire load is located between the axles which are about 3' apart also. I like your heavy use of the new DOT colored tape.

 

[JJT]

BNC, I've heard the same story, only 3 - 4 big guys were used instead of bags of sand/cement/whatever. Less work....

 

[Highbeam]

The tractor and trailer were new in that photo. The manufacturer, PJ Trailers, installed the DOT tape all over. I rather like it. It also runs across the entire tail. The trailer has been a source of great pride. It is a work of art.

It is real weird, I go over speed bumps on my commute and the front of the truck goes up and over then the rear end and then the trailer just floats over it.

That's an 18' trailer including the 2' dove.

 

[JimR]

Check your state regs. Some states require brakes on all axles. I load my trailer so that my truck bumper is an inch to 2 inches lower than what it was before loading. I have a F250 4WD.