Axle Weight Limits

Discussion in 'Trucking Industry Regulations' started by bisonbow, Feb 16, 2008.

  1. bisonbow

    bisonbow Bobtail Member

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    Feb 16, 2008
    Troy, MO
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    Guess everyone understands the 12,000/34,000/34,000 for normally configured rigs meaning steer/dual drive/dual rear. What are the weight limits for trailers with split rear axles? Does it make a difference in how far the axles are split? If the weight limit is over 34,000 on split rear axles (I've heard 20,000 each) what happens to the to limits on the steer and drive? Also, suppose a fellow has a flatbed with three axles. What are the weight limitations in this case? Is there somewhere easily accessible that has this information in a user friendly format? Any help will be appreciated.
     
  2. Scarecrow03

    Scarecrow03 Road Train Member

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    The way I understand it is that even with split axles on the trailer allowing for a total of 40,000 lbs, your drives are still held to 34k and the steers 12k so long as you don't exceed 80,000lbs total vehicle weight.
     
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  3. Luman

    Luman Bobtail Member

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    Jan 5, 2008
    Las Vegas, NV
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    What Scarecrow said.
     
  4. Ohnoo

    Ohnoo Light Load Member

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    Keep in mind that even with spreads your still only allowed 80,000 gross without OD permits. And for every driver that will tell you that they regularly cheat the scales this way... Well wait till you hear how loud they cry when they do finally get caught at a scale.
     
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  5. prisonerofthehwy

    prisonerofthehwy <strong>Ball and Chains</strong>

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    Yeah, I think Scarecrows right. It should be in your FMSCR book though. I am too tired to go thumbing through my little green book right now.
    That reminded me of this time in Moab Utah.... turbo blew as I was going up the hill from the hole in the rock, and the Utah State trooper/Dot officer, looks at me, and says with one eyebrow lifted, "So, do you think I can catch you over weight on atleast one axle." Thought he was serious for a second..... I was running barely legal, and was trying to burn off some fumes before I got to the next scale house.:biggrin_2551: I like the Utah DOT.:biggrin_255: Good sense of humor.
     
  6. Native Dancer

    Native Dancer Heavy Load Member

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    Portland, Or.
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    You can licence for over 80,000 with a spread. Weights vary by state.
     
  7. MACK E-6

    MACK E-6 Moderator Staff Member

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    This depends on the distance of spread. 40k is only legal for 10' of spread.

    9' of spread? 39k max.

    You need to consult a thing called "The Federal Bridge/Gross Weight Formula".

    Now steer axles vary depending on the state. With the right configuration, it is possible to be over gross weight but not over on any axles, such as with a 40k trailer axle limit, 34k drive, and 20k steer.
     
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  8. Brickman

    Brickman Trucker Forum STAFF Staff Member

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    In CO you don't need to be licensed for 85,000, just don't get caught on the interstate system over 80,000!!!

    In WY I think you can license for up to 87,000 or 90,000 as long as you can bridge the weight.


    The only way I would have a flat or stepdeck is to have a spread axle. It makes getting your load spread out right SO MUCH easier. Once you learn your equipment and if you have air gauges and figure out what PSI means what in terms of axle weight you can load to with in 500 lbs of the steers and drives every time and then leave the rest of the weight on the trailer with no concerns of correct axle weights. Only concern then is gross.
     
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  9. Scarecrow03

    Scarecrow03 Road Train Member

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    I can't make heads or tails out of that "thing"
     
  10. MACK E-6

    MACK E-6 Moderator Staff Member

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    Well, theoretically there is a myriad of different ways an officer can weigh your truck under the bridge formula, but they're really only concerned with two. Those are called "inside bridge", and "outside bridge". Bridge formula measurements are done "on center", and are rounded off to the nearest foot.

    The only difference is that "outside bridge" includes your steer axle.

    It's simple. To gross 80k on 5 axles you can have no less than 51' O/C on your outside bridge. In other words, the dimension from the center of your rear trailer axle to the center of your steer axle may be no less than 51'

    Also, you need at least 36' on your inside bridge for both of your tandem assemblies to total 68k. Inside bridge is from your rear trailer axle to your front drive axle. If you have a shorter trailer, and are therefore subject to a lesser amount of inside bridge weight, you can still have 34k on one tandem. But the total of that and the other tandem can't be more than what's prescribed in the bridge table.

    By the way, since the bridge formula is federal, it applies in every state. However some states, and judges, choose to ignore it because it's nothing but a money racket.
     
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