There is an idiot light on the trailer, a clear marker light that is supposed to come on whenever the dump valve is powered. There is a problem with trailer mounted lights and switches; the switches get salt and moisture in them and close the switch even when the switch is positioned to open. Those lights tend to get damaged in unloading and re-loading the containers. The best way I have found is to check and make sure the air-bags come up and to periodically check them when it is wet. The valve is not activated unless the lights are on so I have waited until daylight to drive if I can't reliably shut off the dump valve. The damage to the trailer and the tires if running loaded on one axle is nothing to sneeze at, either.


The reason we dump is not so much for the tires as for the wheels studs and hubs, they take a terrific strain from turning sharp in the gravel and dirAJ

well here goes...just bought a truck an trailer....trailer is a 48' spread axle with a 10'2" spread.
now my question is what IS the correct way to load it?
this is the first spread ive ever pulled and since i own it i dont want to screw it up
besides being able to put 40k on the rear of the trailer making axle weights 12,28 &40 what else should i know? or should i just stick with the tried an true method of 12,17,17,17,17?
well now that ive made myself look like a dee-ta-dee go ahead an have at me
thanks guys

You have to know the weight of what you are hauling and where to load it on the trailer. You want to load it heavy on the rear You can put 40k on the spread. But it's not adjustable so you have to know where your weight is because once it's on there you can't slide the tandems to distribute the weight

One of the easist things you could do is put a gauge on the back of the cab that is plumbed into the truck's airbags. I load my truck all the time from railroad cars, and I use the gauge to load myself. If I bring the gauge up to about 61 pounds, I have right at 33k or so on the truck tandems. Some of the trailers are air ride as well, and we use a gauge on them to determine their weights. They don't cost much to install, and once you use it a few times, you will be able to easily get your weight set where you need it every time thereafter.

I load myself 2-3 times a week sometimes, and I can load 48-50k on a trailer each and every time by using the gauge.

By the way, there is no 12, 17,17,17,17 loading. It's 12, 34, 34. The reason for that is to have a pair of axles meet the legal definition of a tandem axle, there has to be a mechanical or pneumatic linkage betwen the two axles that equalizes the load. So each half of a tandem will always carry 50% of the load. If it is an air ride, the bags on the axles will be plumbed together so that they are equalized. If it is a spring ride, it will have a set of spring hangars or walking beams that equalize the loads.

well the KW has a dash guage for the air bag psi (61 psi is about 33k)....trailer used to have one...i prolly outta get it plumbed back in soon
so from the way you put it burky...I should be scaling 12,34,17 &17 or perhaps 12,28 & 40?

as for the 12,17,17,17,17...if you've ever hit the poodunk wiegh station by ennis or twin bridges...thats how the mt DOT guys do it...i dare ya to be 1 lb over...its montana after all...they're either huntin deer an elk or truckers...and as long as its legal, they get ya

My point is that if the two axles are intercconnected, either mechanically or pneumatically, they are equalized and have to be the exact same weight as each other. The DOT may check to see if there is a difference because it is possible to have a lift axle and run one heavy while the other is up, but by their very design, they equalize out and the weight has to be split evenly.

The logic behind a dump valve on a spread being illegal is that it interferes with the load equalizing function of the air ride on the axles.

As for what you can scale, it is up to 40 on the spread, up to 34 on the tandems, and up to 12 on the steers, as long as the overall gross does not exceed 80. Any combination is okay as long as you don't break the individual limits and don't break the gross number. What you have is a trailer that is simply less sensitive to differences in the weight and gives you a little bit more leeway in how you load it..

I didn't like loading the rear of the trailer that heavy if I could avoid it. Some times I couldn't. Like with a piece of machinery you just can't do it any other way.

But even if you have a 48,000 lb load and you center the load between a foot and a foot and a half back of center of the trailer you'll never have a problem with too heavy on the drives.
For example if you have 16 skids of some thing its two rows of 8. Center row number 5 in that sweet spot just back of center and you'll never have an issue.

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