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Thread: Trailer Towing Question

  1. #11
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    Quote Originally Posted by pop058 View Post
    I would have thought it would "Crab" as the trailer tow point is not in the centre of the trailer axle.
    Trailer will always tow straight, no matter how for offset the tow hitch is on the tow vehicle - just that the centreline of the trailer will be offset from the centreline of the tow vehicle by the same distance as the offset of the tow hitch on the tow vehicle.

    As far as the trailer is concerned - the tow point is ALWAYS in the centre of the trailer axle.
    Cheers .........

    BMKAL


  2. #12
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    the trailer will go where ever its towed.

    The axles orientation to the tow point is what sets the dangle of the trailer.


    if you offset the hitch on the tractor the trailer will tow in the same orientation but offset by that amount.

    if you kink the draw bar it will do the same thing.

    Cornering geometry will be upset compared to a centrally aligned setup but not unmanageably.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
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  3. #13
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    Quote Originally Posted by BMKal View Post
    Trailer will always tow straight, no matter how for offset the tow hitch is on the tow vehicle - just that the centreline of the trailer will be offset from the centreline of the tow vehicle by the same distance as the offset of the tow hitch on the tow vehicle.

    As far as the trailer is concerned - the tow point is ALWAYS in the centre of the trailer axle.
    The example I am concerned with is C. The vehicle tow hitch is centre.
    OK to exaggerate join a solid pole to one front corner of the trailer, still parallel to the centreline. Will this still tow straight but offset by half the width of the trailer?
    Last edited by 123rover50; 30th May 2012 at 07:35 PM. Reason: correction

  4. #14
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    yes, so long as it is perpendicular to the axle AND strong enough to resist flexing.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    Tdi autoManual d1 (gave it to the Mupion)
    Archaeoptersix 1990 6x6 dual cab(This things staying)


    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

  5. #15
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    Quote Originally Posted by BMKal View Post
    Trailer will always tow straight, no matter how for offset the tow hitch is on the tow vehicle - just that the centreline of the trailer will be offset from the centreline of the tow vehicle by the same distance as the offset of the tow hitch on the tow vehicle.

    Not relevant to example C

    As far as the trailer is concerned - the tow point is ALWAYS in the centre of the trailer axle.

    We ARE talking about the trailer tow point being off centre


    Quote Originally Posted by 123rover50 View Post
    The example I am concerned with is C. The vehicle tow hitch is centre.
    OK to exaggerate join a solid pole to one front corner of the trailer, still parallel to the centreline. Will this still tow straight but offset by the width of the trailer?
    trailer will crab because (trailer) tow point is not in the centre of the (trailer) axle.

  6. #16
    slug_burner is offline TopicToaster Gold Subscriber
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    I think the trailer will try to crab and therefore try to bend the pole used to attach to the trailer at an offset point. You will either bend the towing pole or have some scuffing of the tyres as the tyres and axle orientation will try to prevent a sideways movement.

  7. #17
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    Quote Originally Posted by pop058 View Post
    trailer will crab because (trailer) tow point is not in the centre of the (trailer) axle.
    Sorry - yes, you're right Paul. Just went back and read example C again. I thought (incorrectly) that it was only the hitch on the tow vehicle that was being moved.
    Cheers .........

    BMKAL


  8. #18
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    Quote Originally Posted by pop058 View Post
    trailer will crab because (trailer) tow point is not in the centre of the (trailer) axle.
    Paul, by crabbing do you mean the trailer will travell at an offset to the tow vehicle, or do you mean that the trailer will want to go in a different direction than the tow vehicle?
    In my limited experience driving tractors with hay balers (36 years ago) the trailer will follow the tow vehicle in a straight line, but at an offset to the tow vehicle. Hay baler drawbars can be offset by 3 - 4 feet.
    The wheels will steer the trailer into following the tow vehicle. (at an offset)

    Cheers, Mick.
    1968 SIIa SWB
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  9. #19
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    I am inclined to agree with pop058 and slugburner.
    If the hitch at the tractor couldnt pivot then it would have to pull straight as Dave says but because it can pivot I think the leverage on the trailer pole will tend to twist it on an angle, that will make the wheels try to steer out to the side untill running parallel to the direction of travel. But the pulling force is trying to pull it centre again so scuffing the wheels.
    Perhaps this would start to happen at minimum offset.
    The example C at 200 mm might see the trailer run at 180mm off the centreline with little scuffing.
    The exagerated example with 600 mm offset might see the trailer run at 500 mm off the centreline with the wheels acting like disc plows.
    I dont know, but we could keep increasing the offset outside the limits of the trailer untill wheel contact with the ground is lost altogether and it is just dragged along corner first.

    Didiman

  10. #20
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    Quote Originally Posted by isuzutoo-eh View Post
    I presume that a swinging drawbar means it is pivoted at both ends? If so then for example C it will crab, it'll be trying to steer towards the side with greater drawbar offset.
    If the drawbar is rigidly attached to the trailer it'll pull straight unless getting close to jack knifing in the direction of the smaller offset.


    I made up a crude model using a pencil as the axle, two rubber bands for wheels and a loosely tied piece of string for the drawbar. When the string is near enough on centre the 'trailer' pulls close enough to straight until the difference in rubber band wheels changes things. If offset to 1/3rd from a wheel, the axle slews rapidly with no chance of a straight pull.

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