Controlled, Stab, Snub, Threshold braking

The methods being discussed here are generally used without the Jake, or in leu of the Jake.

 

When I started in '63 the steady pressure was the way to go, that was before "jakes". After "jakes" , the "snub system" became the accepted and the best way to take a heavy load down a mountain. I will admit that after years of using "steady pressure", it was real hard to make the change, but after I finally convinced myself, I can assure you that a truck with "jakes"(if they are any good) it is much better to use the "snub system".

Here where I live, I go down a 4 mile grade about everyday and right at the bottom, I have to make a right turn and I run real heavy and my "jake" ain't the best either, but I have been "snubbing" for years and not one bit of smoke or smell from my brakes and when I make the right turn at the bottom, I almost have to stop to do so.

 

Grade is irrelevant. You can apply <15lbs. (apparently) forever w/o smoking properly adjusted brakes.

I didn't believe it either, until I tried it dropping into Baker SB on 15. The engine was a neutered gutless M-11, and the jake on that thing was little better than useless (maybe less better if you considered it effective for anything other than making noise).

I smoked my maladjusted brakes a little, once, WB on Donner, before I "learned" how to cross Donner w/o touching my brakes. (Big clues on those big signs.)

 

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.For anyone that is really confused by all of this, try reading the Commercial Drivers License Manual. There is only one approved braking method for use on steep or long downhill grades and that is SNUB BRAKING. Snub braking involves applying the brakes firmly enough to feel a definite slowing down which reduces your speed by 5 mph in about 3 seconds and then releasing the brakes. When you speed rises to your maximum safe speed , repeat the snub braking technique.
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.There are two forms of emergency braking techniques: 1-stab braking which involves hard braking and locking up your brakes and 2- controlled braking which involves hard braking but not locking up the brakes. Neither one is appropriate for normal driving down a steep mountain grade.
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.The former method of decending a steep mountain grade is using light steady pressure which is no longer the accepted correct method of descending a steep mountain grade. If you are studying for your CDL permit, NOTE: the light steady pressure method is a wrong answer on the test.
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.I enclose the following address for an article on the web about descending steep mountain grades: http://www.overdriveonline.com/smart-driving-2/

 

Since there seems to be more and more of you (at least or more than "half my age" and less than 1/5 my experience, that keep referring to the practice of "locking your brakes), which is putting the rig in an uncontrolled/semi-controlled skid. I am drawn to the discussion point that somehow, the OP and others have decided to include "emergency braking" with the thread topic of "safely descending a grade" braking techniques.

I read through the article from overdrive and found no mention of "locking up the brakes"....probably because that writer maintained the initial topic of "safely descending" a long/steep grade using "SNUB" braking technique.

One more thing. I don't know if any of you have ever wondered why it is always said; "descend the grade in the same gear you climbed the grade"...? Think back on your driving of the different "hills" we deal with regularly, Donner, Siskiyou, Cabbage, Snoqualmie...along with many of the shorter (yet steeper) grades back east. Are there any grades that are equal on the uphill as they are on the downhill side? Not in my experience! The description is always as if you are running (crawling) up, then cresting, then going right back down...does this event actually happen? Not in my going on 4 million miles, not once!

Now a final note to the OP....you want to bring the "science" into the argument. When you heat up the brakes to the point of "smoking"...I don't really care what the temperature range is since I am not running back to check the pad/drum temperature, nor do I have a temp gauge for such on my dash, once the smoking point has been obtained, the braking effect has been diminished, and as the heat index rises, the friction coefficient declines at a higher percentage, until reaching a no-friction balance...which means you have lost any braking capability. Don't throw "science" into an argument unless you are willing to complete the scenario and explain why you are using the "scientific gob-i-li-gook. Most cases in my time out here, the "scientific BS" is thrown in to try and obfuscate the argument in a vain attempt to recapture some modicum of knowledge once the theory has been presented and in following questioned or disagreed with.

You kids have fun with your pocket calculators and theories....I'll stick to my slide rule and personal gained experience.

 

I just went done cabbage at 25 mph and only touched the brakes up top to slow it down from 55. I dont start slowing till I get to the vista lookout then downshift till your at the gear you need to be to decend. There are 3 warning signs that tell you at the top. Btw, there was a driver on the shoulder halfway down the hill with his brakes smoking. Honked and waved at the dummy as I passed. How many more mountain driving threads do we need?

 

It might be the wrong answer on a test.....a test written more than likely by folks that never had any actual driving experience , but are going on an engineers idea of the correct way to use the "new and better" braking technologies available today. ( read let's design a "better braking system" , and tell everyone buying trucks that the old systems are dangerous) that sells alot of product , especially if you can convince govt officials that it's factual info. But , the simple fact remains , 80,000 lbs is still 80,000 lbs. It was 80,000 lbs in the 50's and 60's and to this day it's still 80,000 lbs , not 1 ounce heavier or 1 ounce lighter. The slow steady even pressure , with the correct gear selection , and the proper application of this method worked well long before the newer technologies came around.......not saying they don't work , but the old way did , and still does work.

 

Tonythetruckerdude: I never said that light steady pressure did not work. Okay?
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.Since we are in the new drivers forum, I do not feel that it is appropriate for me to discuss a technique that is a wrong answer on the written drivers test. Some people in here need to pass that test to get their permits. No offense intended Tonythetruckerdude.
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. Snub braking is what is taught in school because it is currently the only accepted method for descending steep mountain grades and the only braking technique listed in the Mountain Driving section of the Commercial Drivers Manual. You can disagree about the validity of the exam but people still have to pass it to get there CDL.
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.The testing has already been done and the snub braking technique gets lower brake temperatures then light steady pressure. That is a proven fact. Anyone is entitled to their own option; but, no one is entited to their own facts.

 

The debate while interesting is pointless, drivers are going to drive their way and they should. I use snub braking, I will always use snub braking, but if another wants steady pressure then what do I care? We all drive the same passes and most of us get down them everyday just fine so both methods must work.