Weight scale accuracy???

[Meghan]

I wanted to share this with you guys and see what you think. While going through my whole registration fiasco we were trying to get the camper weight as low as we could ( it might have made registration easier). Originally it weighed 1220. We were optimistic that by removing everything we could get it down a few hundred lbs. So we took everything out. Including a heavy shelf and jacks. We went to a cat scale and weighed it again... 1220!!!!! I was like what!?!?! I lugged some serious stuff out of there, even if they went in 20 lb increments it should have changed. So we called CAT And asked them. What they told us was the scales were made for very heavy loads. And below a certain weight they are not accurate. Really????? Have any of you experienced this??

[Donna D.]

For this very reason, ya gotta love all the work Frederick puts in to weighing trailers at the Oregon Gathering which I think are pretty dang accurate for fully loaded for camping trailers.

But yeah, I've heard the same thing as you Meghan.

[Mike Magee]

I had wondered about that.

[Sandy From Fla.]

Hi All, We ran into the same problem in june we had to take our Scamp in to
get it weiged for our registration at a local truck stop the weight had to be unnder 2000 LBs inn order to not need a title, that we don't have. we tried with the camper empty only what was nailed down, and it was 1290lbs they were real nice and tried to help us by trying several times on all 4 parts of the scale. When one time it came to 1850 we said OK thats it. He wrote up the ticket but I'm still not sure we have an accurate read but we got our reg. The owner did say it was verified with a minimum weight at 1500, we think it's min. was 2000lbs because we even steped on the scale with the trailer and 3 people and the weight read 20lbs less! ??? we are going to check it at other places just to make sure we start with some good numbers. Wheres Frederick when when we really need him. LOL. (say, Frederick how would you like a florida vacation??????). Good luck Maghan

[Frederick L. Simson]

Originally Posted by Meghan

Originally it weighed 1220.

We went to a cat scale and weighed it again... 1220!

What they told us was the scales were made for very heavy loads. And below a certain weight they are not accurate. Really?

This is a common misconception. Many people confuse accuracy with discrimination. By statute, a weighing device in a commercial application must be accurate within it's allowed error tolerance throughout it's range. But your trailer is small enough that it is conceivable that your trailer may have actually been up to 50 pounds lighter the second time but that difference is within the allowed error tolerance ...
generally +/- 0.1% of the applied weight, or possibly a total of two increments of discrimination, whichever is larger.

This is from my "Rule Book"

Theory of Tolerances:
Tolerance values are so fixed that the permissible errors are sufficiently small that there is no serious injury to either the buyer or the seller of commodities, yet not so small as to make manufacturing or maintenance costs of equipment disproportionately high.

Obviously, the <scale> manufacturer must know what tolerances his equipment is required to meet so that he can manufacture economically.

His equipment must be good enough to satisfy commercial needs, but should not be subject to such stringent tolerance values as to make it unreasonably costly, complicated, or delicate.

All the CAT rep was trying to say is that legally, you did not suffer serious injury. If you felt that you did, the proper recourse is to report your experience to the County Department of Agriculture, Bureau of Weights and Measures where the scale is located.

[Frederick L. Simson]

Originally Posted by Donna D.

For this very reason, ya gotta love all the work Frederick puts in to weighing trailers at the Oregon Gathering which I think are pretty dang accurate for fully loaded for camping trailers.

Just before I leave to attend the gathering, I calibrate my wheel weighers so they are accurate. The weight I use has to be re-certified by the State of California every 2 years.

[Raz]

"By statute, a weighing device in a commercial application must be accurate within it's allowed error tolerance throughout it's range. "


I wonder what the range of a commecial scale designed to measure large trucks is? Could it be that in some cases we are just too small to be within the accuracy range of the scale? Raz

[honda03842]

We drove through our transfer station's scales to weigh our trailer. Generally they are designed for vehicles our size, not 18 wheelers.

Over the years the transfer station's scales have been very consistant for our Honda CRV on dump runs and I suspect also for our trailer.

To measure tongue weight we use a bathroom scales.

Norm

[Darwin Maring]

Weigh at a grain elevator or junk yard.

[Borden]

I agree it is our trailers are too light for some scales (below the minimum working range of the scale)
We have a scale that is used for weights at local garbage dump for bulk disposal (trailer loads) hope it’s rang is low enough to be accurate at checking our trailers weight
I do know the tongue weight as it is light enough for the bathroom scale (Less than I weigh at times)

The closet door sheet states Class II hitch required and says trailer weight is over the 200/2000 of a class I hitch
The trailer equipment list on the spec sheet includes items never installed on our unit in the total weight and puts tongue at 202 lbs. They do not make a class II for our car that is why class III was installed

[Frederick L. Simson]

Originally Posted by P. Raz

I wonder what the range of a commercial scale designed to measure large trucks is? Could it be that in some cases we are just too small to be within the accuracy range of the scale? Raz

In California, a "normal" truck scale is 70' long and 10' feet wide. It will read in 20 pound increments, from Zero to 120,000 pounds. The Automatic Zero Tracking circuit in the indicator will reset any "tiny" value below 60 pounds back to zero; weights 80 pounds and above will register on the indicator.

County Weights and Measures officials normally conduct weight response tests in 1000 pound increments from 1000 pounds up to 80,000 pounds at least once every 2 years.

They test increment "Break" response so that the scale will register one increment above 50% of that increment and on increasing weight the scale will display the next increment above 150% of the preceding increment. (This means that any pressure on the above scale must register 80 pounds from 71 pounds through 90 pounds, and at 91 pounds it must register 100 pounds.)

Allowed error is called "Maintenance Tolerance". When a test weight is applied to the scale, any reading within the tolerance window is considered an "accurate" reading. The tolerance chart for our example is:

Test Load__________________________Maintenance Tolerance
_____0 lbs through 10,000 lbs______+/- 20 lbs (40 lb window)
10,020 lbs through 20,000 lbs______+/- 40 lbs (80 lb window)
20,020 lbs through 30,000 lbs______+/- 60 lbs (120 lb window)
30,020 lbs through 40,000 lbs______+/- 80 lbs (160 lb window)
40,020 lbs through 50,000 lbs______+/-100 lbs (200 lb window)

So, for Meghan's Play-Pac, the variance could be the Maintenance Tolerance Window plus the allowed Break response.
This means that any Actual Weight between 1196 pounds and 1245 pounds could display as 1220 pounds and be "accurate" for that scale.

[Raz]

"So, for Meghan's Play-Pac, the variance could be the Maintenance Tolerance Window plus the allowed Break response.
This means that any Actual Weight between 1196 pounds and 1245 pounds could display as 1220 pounds and be "accurate" for that scale."

So in your example Meghan could have removed almost 50 lbs of stuff from here trailer and because of the tolerance she would get the same result. And knowing the trailer is within that range is certainly close enough to tell what effect it will have on the tow vehicle.

Your belt has a hole every inch. If your waist is 34 1/2 " , your belt will either be a little tight or a little loose but it should still keep your pants up

Thanks Frederick.