weight balance on trailer axles

[hhendrix]

I weigh each axle when I get a chance. I believe that a balance should be on the Airstream axles. I have always been able to get each axle within 300 lbs of each other with a full water tank and empty holding tanks.


Fast forward to new 2020 F250 which is taller than my 2011 F250, so I've trying to adjust the hitch. I just checked my axle weights on the way to Maine and the front trailer axle is 700 lbs more than the rear axle. Total trailer weight of my 27' FB is 7700 lbs. Any thoughts on this?

[uncle_bob]

Hi

Just checking: we are talking about the axles on the trailer and not the axles on the truck ... right?

The big issue is that each trailer axle has a weight limit. You don't want to go over that limit on either axle. Having a ~10% difference between them does chew into your trailer payload.

The F250 (especially the FX / 4x4 version) is quite tall. One *might* say insanely tall ... Typically a special shank is used that goes quite low relative to the receiver.

https://www.etrailer.com/Accessories...e/RP54998.html

is a totally randomly selected example of one.

What I find a bit confusing is that usually nose low is what gets you more weight on the front axle. That would suggest the hitch actually needs to be a bit higher than you have it.

Next question: how do you have the weight distribution set up? How much on the front truck axle and how much on the rear?

Bob

[Bill M.]

Is the trailer level? If it is level or down 1 inch maybe in front that is what I go by. I have never weighted the axles separately. I guess I should because that sounds like more difference than I would expect.

[thewarden]

This is pretty straightforward. On level ground with a level trailer, front to back and side to side, the axle weights should be very close to the same.

When you are hitched up on level ground, is your trailer level front to back? A heavier front trailer axle suggests that your trailer is nose down when hitched up.

[Fungus]

Opposite problem here: trailer level but rear axle much heavier. I dropped the nose one notch. Now the axles weigh nearly the same...maybe 150# difference (can't remember exact difference). The adjustment put the PP in line with the installation recommendation. I had installed the PP on a flat but not level incline and had cheated one notch.

F-150 FX4 max tow
2017 International Serenity ~7000# fully loaded
ProPride hitch
Dexter lift

I also noticed that the front lift was about a half-inch less than the rear (when compared to the original non-lift configuration.) Not sure if it affects the weight distribution enough to change it.

[guskmg]

Post #4 thewarden: I agree with your analysis. It is the old "wheel barrow" principle if you look at the TT from front to rear. Also, the solution would change if you raise or lower the spring bars. That could induce some instability on the total system. I have noticed that with my old Hensley if one or both jacks unwind a bit due to road insulations. Hensley says to run them all the way up and leave some torque on them. He could need a lower shank.
guskmg

[hhendrix]

Sorry for the delay in response, we were out of cell range. Here is the story. I’ve been doing this for a long time helping members set up WD systems and at newbie rally clinics. In Oregon there are many unmanned AG weigh stations, so it’s easy to find time there. I’ve spent as much of 2 uninterrupted hours setting up systems. I have always felt at balance on the trailer axles independent of the TV contributes to a more pleasant and safer towing expereince. These Cat weighs I’ve seen here never never separate the trailer axles, only gross weight. So they never catch trainer axles way out of balance.
I’ve owned Airstream trailers for 13 years and on my second trailer and 3rd truck. This 2020 is much taller than previous Fords. The point of my posting was to see what other have determined the axle balance. But in my rants here about weight appears the vast majority don’t look at the issue.

Ford front axle 4990
Ford rear axle 4750
Total 9700

AS front axle 4200
AS reat axle 3500
Total 7550

I made adjustment to the hitch on the new truck including a new stinger that gave me more adjustments. I thought I got it pretty level but comments from you made me check again and sure enough, the front is one inch lower than the rear using the trim line. One inch doesn’t sound like much but I know from experience one inch on a long trailer can be significant. It’s like guskmg said the wheel barrow effect.
So now I’m going to have to so some fine tuning but I’m on the road to Maine. My stinger raises in
1 1’2 increments. The ball also has an incline feature that you can also use to adjust height. Then there are the chains. So this is going to take awhile and have to wait until I get home. I have a friend on the way with the right tools but that’s not until NH.

Keep in mind axle weights are dynamic. That is you start off with one but maybe tanks get some fill, shoping, Lucy’s rock collection, that 200 lb anvil you found at a garage sale, it is a constant state of change. But I fell it is good to start your trip balanced and manage it on the road.

Thanks for your input. WBCCI #284

[uncle_bob]

Hi

Looking at the front/rear axles on the truck, it does not appear that WD is contributing to the problem. ( = the same process that shifts weight front/back on the truck also impacts trailer axles a bit).

Bob

[Fungus]

Originally Posted by hhendrix

I thought I got it pretty level but comments from you made me check again and sure enough, the front is one inch lower than the rear using the trim line.

What do you mean by "trim line"?

I measure under the trailer from the frame to the ground as far forward and back as I can get, as per the ProPride instructions. If the trim line is on the side of the trailer body, I wouldn't trust it to be true with the frame.

Follow-up...I just looked at my CAT numbers I took after the adjustment I mentioned...40# difference between front and rear trailer axles at the time of the weighing. Of course, it is dynamic, as you said.

Another thing about weighing your individual trailer axles on a CAT scale: it may not be spot on because the front axle of the TV might be on the incline coming off the scale, tipping the hitch slightly upward (the rear axle acting as a fulcrum) and transferring a small amount of weight from the front axle of the trailer to the trailer's rear axle and TV's rear axle. At least that's how I think it works.

[hhendrix]

Originally Posted by uncle_bob

Hi

Looking at the front/rear axles on the truck, it does not appear that WD is contributing to the problem. ( = the same process that shifts weight front/back on the truck also impacts trailer axles a bit).

Bob

Yup, that's why I have to adjust the entire system.

[hhendrix]

Originally Posted by Fungus

What do you mean by "trim line"?

Follow-up...I just looked at my CAT numbers I took after the adjustment I mentioned...40# difference between front and rear trailer axles at the time of the weighing. Of course, it is dynamic, as you said.

Another thing about weighing your individual trailer axles on a CAT scale: it may not be spot on because the front axle of the TV might be on the incline coming off the scale, tipping the hitch slightly upward (the rear axle acting as a fulcrum) and transferring a small amount of weight from the front axle of the trailer to the trailer's rear axle and TV's rear axle. At least that's how I think it works.

I have done both and have found the trim piece around the bottom of the shell to be fairly accurate.


Good point. That's just one of the issues with CAT scales. Again, I'm fortunate with all the state run ag scales around Oregon. I can weigh, then adjust, then weigh again until it's perfect. I have one less than 20 miles from my shop that is open all the time.