Cat Scale Frustrations

[colby]

I'm not quite sure how this can happen on a scale that is supposed to be calibrated so well, they have a guarantee that their scale is accurate. Here's what happened today...

I finally got enough mileage on the new TV that I can pull the trailer. I just want some rough numbers, so I load up a little bit of weight into the cab to simulate my DW (She really isn't the same as a box of windshield washer cleaner and a couple of big bags of flour...). The trailer wasn't perfect either (no food in the fridge, no clothes), this was more about confirming height of hitch, making sure the truck responds, a little backup practice (played with the backup assist, but I digress...).

I head out to the CAT scale and fill up. I then do my three weighs. I did the TV first with the hitch and bars still on. I then hooked up the trailer and did the weigh with the WDH disengaged, and finally I did the weigh with the WDH engaged. I had to do this one twice... Here are my numbers:

1. Just the Truck:
   1. Steer Axle - 3252 pounds
   2. Drive Axle - 2684 pounds
   3. GVW - 5940 pounds
2. WDH Disengaged:
   1. Steer Axel - 2970 pounds
   2. Drive Axel - 3652 pounds
   3. Trailer Axles - 3256 pounds
   4. GCW - 9878 pounds
3. WDH Engaged (first time through):
   1. Steer Axle - 3146 pounds
   2. Drive Axle - 3366 pounds
   3. Trailer Axles - Minus 2332 pounds
   4. GCW - 4180 pounds
4. WDH Engaged - Weight 2:
   1. Steer Axle - 3146 pounds
   2. Drive Axle - 3366 pounds
   3. Trailer Axles - 4136 pounds
   4. GCW - 10648 pounds

Somehow I defied gravity with the -2332 pounds for the trailer, but how can it be explained that the GCW increased by almost 800 pounds between weighs 2 and 3 (WDH disengaged and WDH engaged). Has anyone seen that? How do I trust any of those numbers...

[travelingjw]

Based on all the other numbers being correct, it was either a scale malfunction or you did not position the trailer axles properly. If you show the scale operator an error they will let you reweigh. my understanding is you should place all wheels as far away from the edge as possible.

[SloPoke]

Post the scale tickets please...

[colby]

Originally Posted by travelingjw

Based on all the other numbers being correct, it was either a scale malfunction or you did not position the trailer axles properly. If you show the scale operator an error they will let you reweigh. my understanding is you should place all wheels as far away from the edge as possible.

I was pretty much right in the middle, and I got out and checked to ensure that the wheels were sitting where they were supposed to. The operator was having a bit of difficulty. On the first and the fourth weighs, I was able to us ethe app, not sure whet they were doing for the second and third...

The second weigh I am more concerned with the TV numbers anyways and I think those are OK. Everything seems to check out and towing the trailer for the first time was really smooth. I'll try again next spring when I am in more of a camping configuration to fine tune.

[Rustic Eagle]

Originally Posted by colby

snip....... How do I trust any of those numbers...

You can't.

I doubt your WDH transferred 880lbs back to the TT axles: WDH Engaged TT axles @ 4,136lbs ..... minus ...... WDH Disengaged TT axles @ 3,256lbs.

Obviously the CAT scale platform system under the TT axles is having a bad day.

Originally Posted by colby

snip....... I'll try again next spring when I am in more of a camping configuration to fine tune.

Sounds like a good plan.

Bob

[colby]

Originally Posted by SloPoke

Post the scale tickets please...

Here they are...

I'm in Canada, so the conversion to pounds is handwritten to the right

[colby]

Originally Posted by kblast523

Well, 1cm of height and only 'bringing it back, you are still light on the front end.
My former 2015 F-150 would only raise 1/2 inch, (1.25cm) but to drive correctly, I needed to compress with the weight distribution hitch nearly 1.5 inches (3+cm)
My former 2019 RAM 1500 would raise 2 full inches (Timbrens) but with properly tensioned WDH would compress between 1 to 1.5 inches (2.5 to 3.75cm).
My current TITAN equipped with Sumos raises the front end exactly 1 inch, in order to maintain proper handling balance (steering control) I have to put eight full turns in the Anderson anti-sway hitch on both sides. That shifts enough weight to the front to lower the front suspension height 1 inch (2.5cm) BELOW unloaded weight. That would be 2 inches (5cm) below coupled height without the hitch.

Either your hitch head angle is off (needs to tilt toward trailer some) or you are trying to "equalize" your weight distribution without assistance from the tongue jack. Raise it up, flip the bars (or whatever your adjustment device is), double check your ball, let her down. Adjust as necessary.

I pulled this into here as this was a reply to my post on the Tow Vehicle Pictures thread and I wanted to explore it here because looking at it, I am a little confused as to why it is thought I am light on the front end...

Using the existing setup, the recommendations from Ford from page 40 of the Ford Towing Guide for 2020 is that I need to be within the 25% correction value, which for me is as follows:

• H1 - The height of the front fender with the hitch and bars attached but no trailer - 95cm
• H2 - Height of the front fender after the trailer is attached to the ball and the bars are not engaged - 96cm
• Height Change = 1cm
• Reduction amount (1cmx25% = 0.25cm)
• Target height = 96 (H2) - 0.25 = 95.75
• Actual height change = 95 (after bars engaged)

So with that, I am well within the vehicle correction with the WDH.

Now, if I look at my TV numbers from the scale (which I think are correct, it's just the TT numbers that I don't trust from doing more research on this...)

My TV alone has a weight of 3252 on the steer axle. When I load the trailer (no WD), this drops to 2970 or a loss of 282 pounds. Adding in the WD, the steer axle changes to 3146, or a transfer of 176 pounds back to the steer axle. Now there is a difference of 105 pounds between the start and the finish. Is that not enough? I tried finding out a recommendation; however, even Equal-i-zer talks about just brining the measurements back to within spec - https://www.equalizerhitch.com/blog/...-set-up-issues

[colby]

Had a great call with the CAT Scale people today (I had filled out a Contact Me form on their website), and they are re-imbursing me for the failed weighs. In my discussion with them, it appears that the operator was zeroing out the trailer section as I was getting on the scale from their observations. The TV numbers appear to be correct, and the first two weighs were done using the app and seem to be more consistent than the two weighs that the operator "assisted" with.

[RedHorse1]

It looks like pass #3 can be discounted right away and the explanation makes sense (coming from someone who has used but has no idea how the scales really work). However, the numbers from pass #2 and #4 are also suspect. The GVW increased by 770#. The total weight should not significantly change based on bars/no bars. Your rig weighs what it weighs, the bars just change how the weight is distributed.
Below is my weight analysis from our first TT which has similar weights (a bit heavier).

[colby]

Originally Posted by RedHorse1

It looks like pass #3 can be discounted right away and the explanation makes sense (coming from someone who has used but has no idea how the scales really work). However, the numbers from pass #2 and #4 are also suspect. The GVW increased by 770#. The total weight should not significantly change based on bars/no bars. Your rig weighs what it weighs, the bars just change how the weight is distributed.
Below is my weight analysis from our first TT which has similar weights (a bit heavier).

Attachment 64187

Thanks Redhorse, I'm ignoring the trailer weights for now, but I think that the TV weights are correct as they did not move between the 3rd and 4th weighs, and they are in line with weigh 1 and a previous weigh I did to get a baseline payload on the truck a couple of weeks ago (just the accessories and a full tank of gas, no trailer, hitch or passangers in the truck).

On another note, I tried to find that spreadsheet that you have the screenshot of. Any chance of sharing? I'm a bit of a collector of those it seems...