I have been over on the drives by as much as 400 lbs. (500 in winter) and not had issues at scales ... even in CA. If I am a little heavy I will get the extra on the steers and drives (never on the trailer) as many scales will let you go. In my case I have an APU, plus many allow a "fudge factor" for fuel. In fact, I had a scale master in AZ ask me when the last time I fueled. He then said, "Be careful, you're about 350 over on your drives." (I assume he meant keep it slow as it was very hot ... 110+).

OR DOT told me anything over 300 LBS on the 34k limit will get you a nice yellow paper with "Notice to Appear". That was the day I got a ticket for 1.8K over and they will not give you a chance to adjust your load before the citation there either. I think the DOT officer was having a bad day though, he was in a foul mood when I got to his desk.


Live and learn.

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The trouble with the world is not that people know too little, but that they know so many things that ain't so
- Mark Twain

Let's support our new president,
but Obama should remember one thing,
Gray Davis.....

I think it's up to the discretion of the DOT officer. When I ran dumps we were always 500-600 over and never had a problem. I would think that with the APU's that 500 over would be allowable.

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The trouble with the world is not that people know too little, but that they know so many things that ain't so
- Mark Twain

Let's support our new president,
but Obama should remember one thing,
Gray Davis.....

IIRC there was legislation, or at least the suggestion of it, from the federal side to have an "APU weight allowance". Much like the fuel surcharge legislation though, if the states don't buy in then it's not really going anywhere.

At the other end of the spectrum, I have heard of (so take that for what it's worth) guys getting dinged when it was clear the overweight is due to snow and ice build up (what are you supposed to do ... stop on the higway before crossing the scale and knock the snow off?).

You are right though, it largely depends on what kind of night the DOT officer had. (Where's the humping smiley?)

My understanding is that it keeps even traction on all axles of the tractor-trailer. If the weight is too heavy on the drive axles, the steering axle will feel like it is floating, may have harder time getting traction, breaking and steering.

Just my understanding of the idea.

To determine how many holes to increase the trailer wheelbase, use this easy formula. Trailer tandem weight minus drive tandem weight then divide by five hundred. If the answer is a negative number shorten the trailer wheelbase that number of holes. Otherwise, increase the trailer wheelbase.
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When the weight was balanced between the trailer tandems and the drive tandems, I did not notice any improvement in fuel economy. But, I did notice a slightly smoother ride and reduced oil consumption. Going up small rolling hills, the temp gauge did not go to 220 degrees and the cooling fan did not kick on as often which indicates less strain on the motor. Going down small rolling hills, the Qualcomm did not beep as much so my overspeed was reduced.
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The most important change was in decending steep grades. In the portions of the grade where it was not the steepest, I could just roll along with the Jake brake controlling my speed. Not gaining or slowing just maintaining my speed. In the steeper parts, it seemed that I did not gain speed as quickly. This allowed longer periods of time between brake applications while keeping control of the vehicle. If you use the brakes less often while maintaining control, the brakes will be cooler when you need them.
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I used the Snub Braking technique not the no longer approved light steady braking technique. If you are not familiar with Snub Braking consult the Department of Motor Vehicle's Commercial Driver's Manual. On the written test, light steady braking is a wrong answer for the proper braking technique on steep mountain grades.