MXD

I just want to check my math to make sure I have it right so I don't make a mistake. I am going to take 2 readings. One with the trailer and one without. Each reading gives you three measurements, one for each axle. All 3 combined is my total weight, that is straight forward. The other ones I want to find out are trailer total weight, tongue weight and payload.

To find my trailer weight I find the difference between my truck axles loaded and unloaded and add that to the trailer axles, correct?

The difference between my truck axles loaded and unloaded would be my tongue weight, correct?

The total of both truck axles loaded will give me total GVWR which from there I can figure my payload since I will have the empty vehicle weight as well.

whitestar_27

Weigh the truck unladen. Then attached the trailer to the truck and weigh just the truck. The additional wight on the truck is your tongue weight.

f6bits

The “R” in GVWR and GAWR is the *Rating*. That’s the spec on the door sticker that tells you your maximum allowable weight. What you measure is *not* a “rating.” It’s just what your truck weighs so you can compare it to the Rating.

The CAT is three scales. I think you’ve got the positioning figured out. For that second reading, you’ll probably have to back up a bit before you unhook the trailer so the tongue jack sits on the same scale as the trailer axles. Then drive forward to get the truck on the first two scales again.

Let’s say you have scales A, B, and C, with readings 1 and 2

A1 = Loaded front axle (needs to be below GAWR)
B1 = Loaded rear axle (needs to be below GAWR)
C1 = Trailer axles
A1 + B1 = Loaded truck. Needs to be below GVWR. Whatever is left over is additional payload capacity.

A2 = Unloaded front axle
B2 = Unloaded rear axle
C2 = Full trailer weight

C2-C1 = Tongue weight
A2 + B2 = Unloaded truck

AB1 - AB2 = Tongue weight (if all you did is unhitch the trailer)

MXD

I was going to take 2 measurements. The truck by itself and the truck and trailer hooked up with my WD hitch. So it would look like this:

A1 = Loaded front axle
B1 = Loaded rear axle
C1 = Trailer axles

and

A2 = Unloaded front axle
B2 = Unloaded rear axle

Based on that, I was figuring:
A2+B2= total vehicle weight - unloaded
A1+B1= total vehicle weight - loaded
(A1+B1)-(A2+B2) = tongue weight
C1+((A1+B1)-(A2+B2))= total trailer weight

Is that math correct? I am trying to avoid hooking and unhooking my trailer on the scale so I am not monopolizing it. If I can take the time to unhook on the scale, I will. In fact, if I can take the time I would like to hook it with the WD bars and without to see how much is being transferred back to the trailer axles.

Tatunka

That's pretty much how I did it, first weight was the truck with WD engaged (each axle seperate (front, rear, trailer) on all weights), second was WD not engaged, and third was just the truck. That way I could see how the trailer was loading my trucks axles and trailer axles, find the toungue weight (unloaded rear- rear w/o wd engaged), and find any other weight needed.

One thing that surprised me was the weight of my truck, 6458 lbs, with out a driver or gear but full of gas.

I figured out that I should have waited and bought a HD max tow, oh well I put air bags on, cheap man's HD pkg.

IronJoce

Yes you got it right, also take a readings with and without WDH "engaged" so you get how much weight is transfered to the front.

What I do with my 5ver:

Weight all axels, take note.
Go out, lower the jacks just to remove weight from the truck and take more note
Lift the jacks, drive around the the building and take another reading just for fun... sometime there is over 200lbs difference total. Those scales are calibrated for BIG BIG weight... not 3000 - 4000lbs per axels

Let us know the results

Cheers

IronJoce

6458lbs!! That's heavy... last Sunday my truck weighted under 6000lbs with me sitting in, my 5th wheel hitch and 3/4 of a 36gal tank. I know a SCab is lighter but not by 500lbs! Maybe my scale is screwed... or yours... or maybe both ;-)

edit: I went to check my notes. My truck was 5934 as described above...

f6bits

If you’re using a CAT scale, you might as well use that third pad to weigh the standalone trailer.

As far as readings with and without WD engaged, I don’t really see the point (so I’m politely disagreeing). You’ll know how the weight is distributed by A1-A2 and B1-B2. It’d be interesting to see how it compares to C2-C1.

Bottom line is that A1-A2 should be close to zero. Strict interpretation of proper WD setup says that A1-A2 should be a slightly negative number; meaning that the “loaded” front axle weight shouldn’t weigh/sag more than the “unloaded” front axle. My opinion is that A1-A2 can be *slightly* positive; meaning that the front end drops a slight bit to offload some of the weight from the rear axle. I aim for A1=A2.

IronJoce

Well you're right, didn't think about what I wrote... I never weighted my TT only my 5ver.

f6bits

With me and the 7 month old plus ~31 gallons of gas, my truck was 6090.