Advantages of a spread axle trailer?

Discussion in 'Questions To Truckers From The General Public' started by Bobg, Feb 12, 2009.

  1. Daisydog

    Daisydog Bobtail Member

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    Thanks for deciphering my script; yes my question was how am I getting such a difference in my axle weights? Have looked the trailer all over and have not seen any cracks in the frame, but since you said so I'll specifically look for that. There are three valves in a box on the side of the trailer: two manual dump valves (one is possible to be controlled from the cab but not operational that way) and between the two is what looks like an equalizer. I am wondering if that is faulty or if that's possible.
     
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  3. TripleSix

    TripleSix God of Roads

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    Reason for the spread:

    Regular tandem trailers flex in the middle. When going down the road, they flex and bend. This flexing and bending heats up the frame and can eventually cause the metal to crack and fail. A spread axle trailer has an axle towards the center of the trailer. This cuts out alot of the flexing and actually gives a smoother ride.
     
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  4. pullingtrucker

    pullingtrucker Road Train Member

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    I would start by looking into these valves. It sounds like you got a different or modified leveling system. On a typical spread axle air ride suspension the manufacters put the leveling valve on the rear axle with a air line that will have a manual or electric dump valve to dump the whole suspension. Then the line will go to the front axle and the rear axle. On the line going to the rear axle is where the electric dump valve is placed to dump the rear axle air for tight turning. When ya start putting more valves in the system to do different things it gets more complicated. If all else fails go back to this simple system and see where your weights are and go from there.

    On a side note I have seen in the "old days" when we re-arched trailers we would have to install spacer plates on top of the lead axle air bags. But this only happened when we got the arch over 6-7 inches on a 48ft trailer. But most trailers today have little or no arch or the arch is built into the frame.
     
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  5. Les2

    Les2 Road Train Member

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    All trailers flex and bend or they'd break! The flexing of a trailer also helps the ride of it.
     
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  6. TripleSix

    TripleSix God of Roads

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    Reread my post. Now, where in my post does it say that spread axle trailers dont flex?
     
  7. Les2

    Les2 Road Train Member

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    I think you mistook my post to you. There isn't much difference in the flexing of a trailer with or without a spread other than the place it flex's. Maybe this isn't so with a van, I don't know and don't really pay any attention to them.
     
  8. wtm

    wtm Light Load Member

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    Advantages
    Easy to load without overloading the tandem
    pull straighter atleast too me
    Keep the tire dealers in business

    disadvantages
    keep the tire dealers in business
    pain in the arse to back in tight places
    They crack worse from draging the axels in a bind
    I have also noticed that when u put 40000 over the spread the tires tend to blow worse then a tandem even with the same amount "overloaded tandem" this is my experience but it could be because on my spreads theres always atleast one thats about ready to go.
     
  9. KO1927

    KO1927 Medium Load Member

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    Could you explain this with a little more detail? I don't understand why not, if this is possible with the close tandem.

    Apologies if this is sarcasm that I am misreading. Jokes are often lost when translated to the computer screen.

    EDIT: I do see the smiley, just don't want to pass up the chance to increase my knowledge, even if the knowledge is disguised as a joke.
    Thanks.

    -Ken
     
  10. heyns57

    heyns57 Road Train Member

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    Ken, the comment about changing gears while turning with a spread axle was meant as a joke with a lot of truth in it. A spread will drag while turning and therefore cause the truck to almost stop or lose momentum, making it difficult to change gears unless you planned to downshift two gears. With a spread, it is necessary to keep the power to the wheels while turning. A driver who operates a tandem every day will be in for a surprise the first time he turns a corner with a spread axle. Most of us do not change gears while turning regardless what type of trailer we have.
     
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  11. KO1927

    KO1927 Medium Load Member

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    heyns57- thank you for the explanation.

    -Ken
     
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