Empty trailers take longer to STOP

Discussion in 'Questions From New Drivers' started by Rerun8963, May 3, 2011.

  1. Rerun8963

    Rerun8963 Road Train Member

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    I seem to have a person here on these boards, (Tankergirl) who disagree's with what is the truth about stopping a loaded trailer over an empty trailer..

    given weights, speeds, traction, it will ALWAYS TAKE LONGER to stop an empty trailer over a fully loaded one.....I DO NOT give out wrong advice to newbies, how can I when we have videos and book materials that prove this fact..??

    here is one section, from a state CDL Manual mind you on this:

    Section 6.1.3 – Brake Early

    Control your speed whether fully loaded or empty.
    Large combination vehicles take longer to stop
    when they are empty than when they are fully
    loaded. When lightly loaded, the very stiff
    suspension springs and strong brakes give poor
    traction and make it very easy to lock up the
    wheels. Your trailer can swing out and strike other
    vehicles. Your tractor can jackknife very quickly.
    You also must be very careful about driving
    "bobtail" tractors (tractors without semitrailers).
    Tests have shown that bobtails can be very hard to
    stop smoothly. It takes them longer to stop than a
    tractor-semitrailer loaded to maximum gross
    weight.
    In any combination rig, allow lots of following
    distance and look far ahead, so you can brake
    early. Don't be caught by surprise and have to
    make a "panic" stop.


    ----------------------------

    here is yet another from Section 2 of the CDL Manual:


    The Effect of Speed on Stopping Distance.
    Whenever you double your speed, it takes about
    four times as much distance to stop and your
    vehicle will have four times the destructive power if
    it crashes. High speeds increase stopping
    distances greatly. By slowing down a little, you can
    gain a lot in reduced braking distance. See Figure
    2.11
    Stopping Distance Chart
    Miles
    Per
    Hour
    How Far
    The Rig
    Will
    Travel in
    One
    Second
    Driver
    Reaction
    Distance
    Vehicle
    Braking
    Distance
    Total
    Stopping
    Distance

    15 mph 22 ft. 17 ft. 29 ft. 46 ft.
    30 mph 44 ft. 33 ft. 115 ft. 148 ft.
    45 mph 66 ft. 50 ft. 260 ft. 310 ft.
    50 mph 73 ft. 55 ft. 320 ft. 375 ft.
    55 mph 81 ft. 61 ft. 390 ft. 451 ft.
    Figure 2.11

    The Effect of Vehicle Weight on Stopping
    Distance. The heavier the vehicle, the more work
    the brakes must do to stop it, and the more heat
    they absorb. But the brakes, tires, springs, and
    shock absorbers on heavy vehicles are designed
    to work best when the vehicle is fully loaded.
    Empty trucks require greater stopping distances
    because an empty vehicle has less traction



    ------------------

    i really wish she wouldn't go around saying i give out wrong advice...

    how can i, when it's documented.....????

    by the way, this WILL BE IN ALL CDL MANUALS across the country, as well as the training films schools will have to show the students, as it's REQUIRED training material, and questions WILL BE ASKED at the DMV....(the written portion of the tests)
     
  2. Boardhauler

    Boardhauler Road Train Member

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    So.... At the very bottom of a long steep hill I will be able to stop quicker at 80K than I can empty?

    Guess I learned something new today.
     
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  3. jlkklj777

    jlkklj777 20 Year Truckload Veteran

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    Some times people have disagreements based on what they were taught. It is difficult to convince someone that they have been taught incorrectly or were misinformed.

    The best we can do is offer our viewpoint and substantiate it with as may sources as possible. The more supporting documentation offered the greater the chance of correcting the misinformation.

    Keep up the good work Rerun8963.

    Remember; "A wise man can learn more from a fool, than a fool can from a wise man."
     
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  4. Moosetek13

    Moosetek13 Road Train Member

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    Yes, if you took the hill in the proper gear and at the proper speed so as to not overheat your brakes on the way down.
     
  5. M915A4

    M915A4 Medium Load Member

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    Good info for sure,we are taught something similar in H8 class(Army recovery school) or were anyways..lol..empty we are mopre apt to slide then loaded.Thats why most Army units around here will not authorize a truck to go out bobtail if its snowing or raining.
     
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  6. Tazz

    Tazz Road Train Member

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    You should have put the term in General in front of your statement.

    Air Springs and ABS braking systems have changed the dynamics of stopping empty, and as someone posted at the bottom of a hill on clear dry day is far different than a panic stop at a red light on new years day in an ice storm.

    I hate to burst your bubble but you are not 100% correct nor is that book your quoting(shocker a government agency got something wrong I know).






    All that aside let it go. Way more important things in life than winning a message board P off.
     
  7. TruckerGsch

    TruckerGsch Medium Load Member

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    Ok lets put it this way. Say tankergirl weights 125 lbs I weigh 350. She runs to you and stop inches from you do you think it is going to be that easy for me to do the same. lol
     
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  8. blackw900

    blackw900 <strong>The Grandfather of Flatbed</strong>

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    It is foolish to think you can stop quicker with a loaded trailer than an empty in all circumstances....

    An empty trailer might have a tendency to skid a bit more than a loaded but you will usually still stop quicker with the empty.
     
  9. Tazz

    Tazz Road Train Member

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    Or a half loaded 6000 gal smooth bore trailer as opposed to a empty smooth bore.

    As I said qualifiers should have been used. He was quoting a book used to cover basics and not real world or up to date information. Does anyone even run spring ride anymore?
     
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  10. blackw900

    blackw900 <strong>The Grandfather of Flatbed</strong>

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    When all that you know comes from a book....That's all that you know!

    In the "real world" we know what really happens!