Tandem placement and turning radius

Discussion in 'Experienced Truckers' Advice' started by expedite_it, Jan 22, 2022.

  1. expedite_it

    expedite_it Road Train Member

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    I didn't understand Bill's explanation.


    Are you calling the drive wheels "the tandem" here? I know that the dictionary definition of tandems just means two things that work together, but I've never seen or heard anyone call the drive wheels the tandem before. Every other time I've seen or heard tandem in my career, people were referring to the trailer wheels. That's why I have to ask.
     
    Last edited: Jan 27, 2022
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  3. God prefers Diesels

    God prefers Diesels Road Train Member

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    :cool:
     
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  4. Last Call

    Last Call Road Train Member

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    She is very pretty...
     
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  5. Hammer166

    Hammer166 Crusty Information Officer

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    Up until now, you've done a rather good job of walking the line between trolling and just totally clueless. But this comment is a bridge too far.

    @REO6205 is right, there's some good info here regardless, but I'm out before my patience snaps.
     
  6. expedite_it

    expedite_it Road Train Member

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    Ok, if Hammer166 won't explain what he meant when he said that "A 5th wheel centered above the drives means the kingpin moves with the tandem", can someone else explain it please? Even though I've never heard or read anyone refer to the drives as a "tandem" (or "tandems"), I think that Hammer166 means that "A 5th wheel centered above the drives means the kingpin moves with the drives", but I don't know for sure. First of all, Hammer166 refers to the drive wheels as the "drives" in the same sentence. So if Hammer166 calls the drive wheels the "drives", I am hesitant to think that tandems refers to drives since he refers to the drives as the drives. Secondly, the kingpin is always above the drives because the kingpin is connected to the trailer. When Hammer166 says "a kingpin centered above the drives", I am guessing that he means "a kingpin centered more towards the front of the semi-truck than the drives", but I am not 100% sure.

    What does Hammer166 mean?

    I always strive to make myself crystal clear. For example, look at my post #128. I went to the trouble of drawing a picture to explain my definition of a "tighter turn" and a "tighter turning radius". I wish everyone else would strive to be clear as well.
     
  7. InTooDeep

    InTooDeep Donner party survivor

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  8. Hammer166

    Hammer166 Crusty Information Officer

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    Sigh. Just so this fool doesn't confuse anyone else who comes along.

    The drives are a specific type of tandem axle. The context, despite the attempts at muddling, is quite clear.

    Y'all have fun!
     
  9. Wasted Thyme

    Wasted Thyme Road Train Member

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    Well you know a million miles and zero sense. We've all done the math. ;)
     
  10. Sixela918

    Sixela918 Light Load Member

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    I was parked at a truck stop last night at the end of the row where everyone was entering. I started reading this thread, and moved my truck asap.
     
  11. expedite_it

    expedite_it Road Train Member

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    Let me translate this for any new drivers or anyone else who does not understand Hammer166.

    A 5th wheel centered directly above the drives means the kingpin moves with the drives. But if the 5th wheel is forward of the drives, the rotation of the tractor moves the kingpin towards the inside of the turn sooner. One would think this means more off-tracking, but because the 5th wheel is forward of the drives, the kingpin follows a longer arc than the drives, effectively reducing off-track. That's why I said I thought moving the 5th wheel with the intent of changing the cornering behavior wasn't a productive endeavor.

    P.S. Hammer166, did I translate this correctly?
     
    Last edited: Jan 29, 2022
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