questions while learning cdl permit information

Discussion in 'Questions From New Drivers' started by ursus, Nov 29, 2010.

  1. celticwolf

    celticwolf Road Train Member

    1,527
    642
    Oct 10, 2010
    Kittrell, NC
    0
    You logic is sound accept you assume the same tire traction (road friction). An empty trailer does not have the same downward force a loaded trailer does (road friction); therefore, the inertia you are toting will be countered by the lack of traction.
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. Tankergirl80

    Tankergirl80 GangstaGirl

    808
    965
    Jan 7, 2009
    West Texas
    0

    It isn't enough to counter inertia. Tire friction does not grow linearly with the normal force. It is linear at lower weights, but it eventually starts to deviate a bit when you load the tire enough. Where that deviation starts to become significant is completely different for different tires.
     
  4. ursus

    ursus Light Load Member

    75
    26
    Nov 18, 2010
    Indiana
    0
    Thanks for the replies,

    They key thing I figured it was just to prevent someone else moving the truck during the pti but I also thought the key might be used in some other check that had not been covered in the book so I thought I would ask. Out of all the information covered in the pti section a question about the key just seemed odd.

    The stopping thing....I will believe the voices of experience on this....however I am still having a hard time wrapping my mind around it. If I toss a ton of white rock in my pick-up it takes longer to stop because of the greater inertia. But I guess since a semi has so much greater ratio of added weight when full compared to empty it works.


    I'm on to following distances and safe speeds now......I honestly don't see much of what is in the book being put into practice on the roads. Don't think I've ever seen a big rig doing 35 in a 55 during a light rain :biggrin_25525:
     
  5. celticwolf

    celticwolf Road Train Member

    1,527
    642
    Oct 10, 2010
    Kittrell, NC
    0
    If you say so; however, please don't be behind me trying to stop an empty in the same space I am stopping my loaded trailer.
     
  6. Tankergirl80

    Tankergirl80 GangstaGirl

    808
    965
    Jan 7, 2009
    West Texas
    0
    Wait a minute.... that's exactly what I said in my 1st post. I'm simply explaining in the circumstance of NO slippage the laws of physics that rerun told me I was wrong on.
     
  7. Rerun8963

    Rerun8963 Road Train Member

    3,917
    2,012
    Mar 30, 2006
    ova-hereee
    0
    it all makes sense when you start driving.....trust me.....

    and at the DMV test site, if you FORGET to take the key out and out it into your pocket...??

    INSTANT FAILURE.......!!!
     
    celticwolf Thanks this.
  8. celticwolf

    celticwolf Road Train Member

    1,527
    642
    Oct 10, 2010
    Kittrell, NC
    0

    Your pick-up is designed to stop empty.. Another key point that seems to be missed in all the science. Tractor/Trailers are designed to stop FULL!!!
     
  9. Rerun8963

    Rerun8963 Road Train Member

    3,917
    2,012
    Mar 30, 2006
    ova-hereee
    0
    we DO NOT NEED to get freaking scientific here.....we are truck drivers, NOT rocket scientists.......stick with the "formula" we all know and understand. Your scientific mumbo-jumbo does no good for us truck drivers.
     
  10. Tankergirl80

    Tankergirl80 GangstaGirl

    808
    965
    Jan 7, 2009
    West Texas
    0
    My 9yrs accident free tells me I must be doing something right. And don't worry it's my equipment, I care way more about it than you do your company trailer. My inertia physics equation is based on no loss of traction. I already explained that.
     
  11. Tankergirl80

    Tankergirl80 GangstaGirl

    808
    965
    Jan 7, 2009
    West Texas
    0
    So am I.... I'm sorry you don't understand.
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.