I can not remember when I saw a truck stop (Flying J, TSA, etc) that did not have a scale, most often a CAT (brand name) scale. These multi-platform scales give you a chance to get almost every weight figure you will ever need. The cost to me has most often been $8 for the first weigh and $6 for a re-weigh.
Considering that you could hold up commercial traffic by staying on the scale for an extended time here is my procedure to get in and get out. First I visit inside with the employee who will be recording the weight. This is not necessary but I find it makes things work smoothly. I explain that I am a private operator and want to get a multi-platform weight for my personal vehicle and travel trailer. Since the call box on the scale is setup for an 18-wheeler to speak into it from their cab, it is good to let them know you may not be able to reach the call box. That normally gets the employee to watch for you.
Pull onto the scale and get each axle
on a separate platform. If necessary get out and jump up to hit the call button on the box. You want to try and get back into your Tow vehicle while it is being weighed. Otherwise, step off the scale and you can later add half of your weight to each of the front and rear axles of the Tow vehicle.
Once the employee advises you, via the call box, that your weight is recorded, pull off the scales, park and unhitch your trailer. Pull your Tow vehicle back onto the scales, again put each axle
on a separate platform. Do the call box thing again and tell the operator that this is a re-weigh. Remember, if you can not get back in your Tow vehicle, step of the scale and add half your weight to each axle
Pull off the scale, park and go back inside. When you pay the bill you will receive two weigh slips. Each slip will show the weight of each platform. From the first weigh slip you will have the GCVW, Gross Combined Vehicle Weight, which is the combined weight of all axles. In addition you have the 'ready to Tow' weights of each individual axle.
From the second weigh slip you will have the GVW, Gross Vehicle Weight, of the Tow vehicle. In addition you have the individual, unhitched, weights for the front and rear axles of the Tow vehicle. Now use a bit of simple math to come up with the effect of the trailer on the front and rear axles of the Tow vehicle.
First calculate the tongue weight, this is the weight the trailer places onto the Tow vehicle. Add the Tow vehicle front and rear axle weights together on both slips. Then subtract the second weigh slip figure from the first. The difference is the tongue weight.
To calculate the GVW, Gross Vehicle Weight of the trailer, add the trailer axle weight from the first slip to the calculated tongue weight. The result is the GVW of the trailer.
Compare the hitched/unhitched individual axle weights of the Tow vehicle to observe the loading/unloading of weight caused by the tongue weight of the trailer. If the front axle of the Tow vehicle loses weight when hitched this can cause a less than optimally stable Tow vehicle. Perhaps a WDH should be added to your rig or an adjustment made to your existing WDH.
All the weights, CGVW, GVW of both the Tow vehicle and trailer, Tongue Weight and the individual axle weights can be compared to the limits established by the manufacturer of your Tow vehicle, hitch and trailer. Another factor to examine is the tongue weight compared to the GVW of the trailer. This is a huge factor in preventing sway (which is a bad thing!). My personal goal for tongue weight is on the high side of 12 to 15 percent of the GVW.
Since the loading of the Tow vehicle and trailer is not perfect, one side will be heaver than the other, perhaps to a significant degree. Determination of side-to-side weight is more difficult in that many scales are not designed to allow the weighing
of a single side. You would have to locate such a scale and weigh your rig a couple of times, each time with one side off of the scale.
Here is a link to a site with additional info on this subject.
<a href="http://tinyurl.com/cstve7" target="_blank">http://tinyurl.com/cstve7
Sorry for the length of this message, I'll shut up now and go eat supper. Don