Why is it better to have the tandems slid forward when alleydocking?

Discussion in 'Experienced Truckers' Advice' started by expedite_it, Sep 16, 2022.

  1. expedite_it

    expedite_it Heavy Load Member

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    Preface to thread: When I use the word "wheelbase" in this thread, I am referring to the distance from the rear drive axle to the front tandem axle.
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    The other day I was at a receiver to make a delivery that was a live unload. I had to back into a unloading dock. The back was an alleydock type of back. I think that the type of back I had to do is called a 45 degree back. The drawing below is a drawing of the situation I was in when I was making the delivery that I am discussing in this thread.

    alleydock September 16, 2022.jpg

    My truck is the yellow tractor-trailer. I was backing into the loading dock where the two stars are in the drawing.

    I set up for the back with my tandems slid all the way forward. But before I started moving the truck in reverse, I walked to the back of the trailer. I opened up my trailer doors. Then I pulled the button to slide the tandems. When I walked from my tractor to the rear of the trailer, I wanted to handle both opening the trailer doors and pulling the tandem slide button at the same time, so I only would need to walk from my tractor to the rear of the trailer one time. The driver in the truck parked just to the right of the loading dock I was going to back into got out of his truck and suggested that I wait until I backed in to the parking spot to slide my tandems to the rear. He said that it is easier to back with the tandems slid forward because it's easier to get the trailer lined up with the loading dock with the tandems slid forward. He said that I am making the trailer longer when I back by sliding the tandems to the rear.

    I know that sliding the tandems to the rear makes a longer wheelbase. Therefore, a driver has to turn the steering wheel farther when alleydock backing with the tandems all the way to the rear than if the tandems are all the way forward. But so what? The trailer is 53' long no matter where the tandems are. Furthermore, the entire tractor-trailer is going to be approximately 73 feet long (might be a few inches shorter or long depending on where the 5th wheel is) no matter where the tandems are.

    Assuming that the other driver is correct, let me ask the following question: Other than having to turn the steering wheel a little bit farther if the tandems are all the way to the rear, why is it easier to line up a trailer with a parking spot when you are alleydock backing (like in the drawing in the photograph above) with the tandems all the way forward than if the tandems are all the way to the rear?
     
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  3. expedite_it

    expedite_it Heavy Load Member

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    You should create a separate thread for your question.

    Nobody has told me yet: Other than having to turn the steering wheel a little bit farther if the tandems are all the way to the rear, why is it easier to line up a trailer with a parking spot when you are alleydock backing (like in the drawing in the photograph above) with the tandems all the way forward than if the tandems are all the way to the rear?
     
  4. expedite_it

    expedite_it Heavy Load Member

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    Let's put me back in the situation I was when I first set up for the alleydock back (like in the photograph). Right when I completed the set up and pulled the yellow brake valve, the trailer doors were closed.

    The advantage of sliding the tandems before I did the back: I would only have to walk from my tractor to the rear of the trailer ONE TIME. I walked from the truck to the rear of the trailer and opened my trailer doors. Then I pulled my tandem release button while I was back there anyway. Then I got back in my truck and drove the truck forward until the tandems were all the way to the rear. Then I pushed in the red brake valve to pop the tandem pins out. Then I pulled the red valve back out and pushed the truck both forward and backward to make sure the pins were out. Then I did the back.

    The disadvantge of sliding the tandems to the rear after I backed into the parking spot: I would have to get out of the truck and walk to the back of the trailer a SECOND time to pull the tandem release button. In a nutshell, I would have to walk from the truck to the rear of the trailer TWICE.
     
  5. slim shady

    slim shady Road Train Member

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    If there's room I'd rather have the tandems all the way back, To me it's easier without the trailer swing
     
  6. expedite_it

    expedite_it Heavy Load Member

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    So you think that when you are doing a 45 degree alleydock back, you need more forward space with the tandems slid forward than if the tandems are slid to the rear? Why do you think that?

    I've asked several drivers about that on this message board via private messages, and even drivers with a lot of experience give me totally contradictory answers about this.
     
  7. expedite_it

    expedite_it Heavy Load Member

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    Are you ONLY worried about tail swing when you have to make a pull up and drive forward during the back, or are you worried about tail swing when you are actually moving the truck in reverse as well?

    What type of tail swing are you worried about? Please elaborate.
     
  8. expedite_it

    expedite_it Heavy Load Member

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    Maybe you are smarter than I am. So what is intuitively obvious to you is not so obvious to me.

    Furthermore, Why do you care? Why don't you just recuse yourself from my threads? You don't offer any answers anyway.

    Why do you waste your time on my threads? Don't you have anything better to do? You could just choose not to open the threads that I create.
     
  9. Grumppy

    Grumppy Trucker Forum STAFF Staff Member

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    ^^^^^^ This right here ^^^^^^

    If I have the room, I prefer to slide all the way back. If its tight, like a true ally dock, I'd slide the tandems all the way forward.
    To take your preference of "only walking to the back of the trailer only once", most places want you to slide the axles all the way back to be loaded or unloaded.
     
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