Looking for the weight police...interpreting my weights

[ALLOY]

26 minutes ago, Big5er said:

 The problem with truck stop scales is that you get a single weight for each axle. With an RV the weight distribution side to side is just as important as the overall weight. 

The only way to obtain realistic weights for an RV is a good set of portable wheel load scales. 

To get the side to side weights I've been thinking of putting (using Bigfoot Leveling) the trailer up on blocks equal to the height of a wheel scale. Each wheel would then be weighed one at a time. Renting a wheel scale is $50.00/day. 

 

[Dollytrolley]

On 11/13/2017 at 11:57 AM, Chad Heiser said:

Finally got my loaded truck/5er weighed.  Still have to get the unloaded 5er weights.  That will happen in a week or two.  

Truck only (hitch installed)

Front axle - 4740

Rear axle - 3880

Total truck weight 8620

The above weights are self explanatory.

Truck with loaded 5er attached 

Front axle - 4820 - front axle weight increased by 80 pounds.  This is part of your pin weight.

Rear axle - 7120 - rear axle weight increased by 3240 pounds.  This is also pin weight.

Your total pin weight by adding these two numbers together is 3320,.

Truck and 5er front axle only - 18420 - I'm not sure exactly what you mean by this.  If you mean only the front axle of the trailer was on the scale and the rear axle was not and you assume your total combined weight is correct at 25600 then your rear trailer axle weighs 7180 lbs (25600 - 18420 = 7180).  This does not match the calculations below.

Total combo - 25600 - Did this come straight off the weight ticket or did you calculate it somehow?  I get 26440 for your total weight.  See below.

5er (both axles) attached to truck - 14500 - This is self explanatory and should be easy to calculate on a typical truck scale.

5er (rear axle) attached to truck - 6860 - I'm not sure exactly what you mean by this and it doesn't match above numbers.  Was this a calculated number you came up with or did you just place the rear axle of the trailer on a scale by itself?  If this number is assumed to be correct, then the front axle of the 5er is 7640.  I came up with this by subtracting your listed rear axle weight from the total 5er axle weight (14500 - 6860 = 7640).  This does not match the calculations above and is way to much spread in weight between an axle pair on a trailer.  Assuming these numbers are correct (which I am not sure of), this would tell me your trailer is sitting very nose low adding weight to the front trailer axle and removing it from the rear trailer axle.

Also, if the combined weight of the two vehicles (truck and 5er) was 25600, that does not add up when you add the loaded truck front axle (4820) + the loaded truck rear axle (7120) + both 5er axles (14500).  These numbers give 4820 + 7120 + 14500 = 26440.  I'm not sure how this came about or why it doesn't match the number you list.

If I am reading the numbers correctly;

Pin weight is 3240 (loaded rear axle - unloaded rear axle = pin weight)  - Your pin weight also includes the load added to the trucks front axle.  The pin weight will equal the total combination weight (you say 25600, but I'm not sure if that is correct) - total trailer axle weight (14500) - unloaded truck weight (8620).  With your numbers that is 25600 - 14500 - 8620 = 2480.  This seems very light and doesn't match above.

5er weight is 16980 (total combo weight - truck only weight = loaded 5er weight) - this is correct, assuming your numbers are correct (which I am not sure about).

 

Some of the other numbers don't add up though.  Am I overthinking it?

 

At least I am within parameters.

Truck GVWR - 13000

GAWR F - 5600

GAWR R - 9375

Truck GCWR - 29200

5er GVWR - 18465

GAWR - 8000 (x2)

Listed CCC- 2822

I've messed around weighing a lot of things much of my life and ..........RV Weighing can be ....."interesting" at times......

In "concept" the "Theory" of weighing a RV rig should not be..........rocket science ...........but seems some days RV weighing can be pretty darn frustrating........

Where does one start..........well a lot of folks seem to like to try the local truck stop CAT scales and often it seems to yield a somewhat mixed bag of ........various weights .....sorta

Truck Scales tend to be big "Instruments".........."instruments" have ......."Tolerances" and ........."Hysteresis" (think a gauge of some sort that tends to be a bit "sticky" .....like you place 100 lbs on the scale and the scale measures 100 lbs however the dial needle sticks at 88 Lbs due to sticky / friction of the gage mechanics).

Then there is scale "Unit Tolerance", this is the scales actual designed unit measure such as 20 Lbs per unit and that unit maybe +20 lbs and -20 lbs of the actual weight so in a real world you might place exactly 1,000 on our scale and it might read 980 Lbs, or 1,000 Lbs or 1020 Lbs and ALL of these Three readings are correct WITHIN the "Tolerance" of the scale..........Now things can and sometimes get a bit tricky..........some truck scale have a +40 /-40 Lb tolerance some are +50 / -50 Lb Tolerance and some can be +100/ -100 Lb and then to make things more interesting mix in a "Hysteresis" of say 100 Lbs and repeat reading can be all over the map…...such as 10,300 Lbs including -40 lbs Tolerance and -110 Lbs of Hysteresis for a actual weight of 10,450 Lbs…….next loop around the scale with the same rig you might trip the scale on the + plus side and observe 300 Lbs difference with the IDENTICAL load…….

 

Next the RV…...hummmm

RV trailers tend to have ……..cheep suspensions that can exhibit somewhat strange pressures on scales……the basic travel trailer often is a tandem axle with a with Inverted “T” center-pivot-walking-beam spring shackle suspension with fixed fore and aft shackles…...for the most part this simple basic suspension tends to do a fair job of allotting the trailer axle potential mass loading between both of the axles however this system has limits of operations and then once those limits are breached axle loading becomes out of balance.

Some of the higher end RV trailers tend to be fitted with Torsion pivot independent suspension and most folks rave about this type of suspension however………. Please consider that unlike the walking beam the Independent suspension has no “Natural- load-center-piviot to try to equalize the trailer major mass to both axles………

It is Vital to attempt to keep torsion axle trailers very level fore and aft when hitched to the tow vehicle.

And of course it is often stated that some like 57 % of ALL RV units on the road have one or more tires that are overloaded so as often stated each tire position needs to be measured and as a personal rule I try to have NO tire exceed 80% of rated load but this can be hard to do with RV units being made with high empty weights and low payloads……..poor design and cheep parts……

 

Drive on……...(RV's often ……...Weighty subjects)

 

[packnrat]

i did  not read every posting.

but get to a "cat" scale. stop where each axle is on a differnt platform. ( two axle rv?).

in some states  ( like here in ca) you MUST talk to the weigh master (clerk) first. and state for personl use ONLY or said info is automatically sent to your states dmv for upping your taxes.

[Chad Heiser]

3 hours ago, packnrat said:

in some states  ( like here in ca) you MUST talk to the weigh master (clerk) first. and state for personl use ONLY or said info is automatically sent to your states dmv for upping your taxes.

That is not true.  I have been over Cat scales numerous times in CA and this does not happen.  They have no mechanism to do so and simply do not do it.

[packnrat]

i have been told other wise.

i only know as i know, if i have been lied to. then i would not know different.

[Big5er]

On 5/31/2018 at 7:06 PM, packnrat said:

in some states  ( like here in ca) you MUST talk to the weigh master (clerk) first. and state for personl use ONLY or said info is automatically sent to your states dmv for upping your taxes.

I'm with Chad on this one. I have never seen a scale that required your drivers license or vehicles license plate number in order for you to weigh. The individual states are still using an antiquated system for sharing vehicle license and drivers license information.  Half of the states do not even list a vehicles registered weight on the registration info they share with other states. They do not have a fancy system for sharing the weight of a vehicle, especially since they cannot prove that vehicle is violating a law in its' home state. 

I think someone is pulling your leg.

[packnrat]

could be. 

i had to show nothing. they got plate info on video cams. 

only stated "for personal use". 

 

but i would not put it past ca do this for more tax moneys. as brown has to build his toy train.