Controlled, Stab, Snub, Threshold braking

Discussion in 'Questions From New Drivers' started by double yellow, Nov 20, 2014.

  1. double yellow

    double yellow Road Train Member

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    Controlled braking: Light (5-15psi), steady brake application combined with proper gear selection when descending a grade at your safe speed. This method was taught for years but is no longer recommended in the manuals. Done properly, it will not smoke your brakes.

    Snub braking: Firm (20-30psi), short (3-5 second) brake applications combined with proper gear selection when going down a grade. Slow to 5mph below your safe speed, release brake, and reapply once you reach your safe speed.

    Stab braking: Hard (90+ psi) brake application, release when wheels lock, reapply when they resume rolling, & repeat until stopped. This is for emergency stopping with old (pre ABS) equipmemt with inexperienced drivers. Still mentioned in many cdl manuals, but is poor technique compared to threshold. This IS NOT used to maintain speed downhill!

    Threshold braking: Firm (30+psi), steady brake application used for emergency braking. Lift slightly if brakes lock until the tires resume rolling (pre ABS) or maintain pressure at which point you feel/hear ABS begin engaging. The goal is to maintain brake pressure at the point just before the brakes lock up. This results in the shortest stopping distance in an emergency.



    Safe speeds for Cabbage Hill:

    Pounds..................MPH
    60,000 - 65,000 37
    65,000 - 70,000 26
    70,000 - 75,000 22
    75,000 - 80,000 18
     
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  3. pattyj

    pattyj Road Train Member

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    Great piece of info double yellow,thanks.
     
  4. HotH2o

    HotH2o Road Train Member

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    Great! Now what's your question?
     
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  5. Ebola Guy

    Ebola Guy Heavy Load Member

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    My question is, when i I am descending a mountain and control my speed by stab braking but the wheels aren't locking up, am I doing it wrong?
     
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  6. HotH2o

    HotH2o Road Train Member

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    You gotta pull the yellow and red knobs!
     
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  7. Bootsie

    Bootsie Bobtail Member

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    Just so I understand, is that before, during or after parachute deployment? And do you recommend single or double parachutes? Finally, I assume color is still the critical factor (we spent 3 full days in CDL school reviewing colors and operating ranges). Sorry for such a basic question but I'm still kinda' new.
     
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  8. Pool6710

    Pool6710 Medium Load Member

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    So these brake check areas. Are these just for sleeping and peeing? do they have a purpose?
     
  9. HotH2o

    HotH2o Road Train Member

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    Color is a state of mind, Bootsie. As for parachute.....wish I had one...
     
  10. double yellow

    double yellow Road Train Member

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    gpsman, Hammer166 and Montgomery Thank this.
  11. Night Prowler

    Night Prowler Medium Load Member

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    Cant you just use an umbrella stuck out the window ? Or would you need two, one for each window ?
     
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