Going down long steep "DOWNGRADE"

Snubbing worked for me = 41 years. Or, keep all of the brakes in adjustment.

 

Glad to heat it worked for you. Like my grandfather used to say "do whatever it takes to get to the bottom alive" It might be 3rd gear 1st gear or reverse just do whatever it takes,and he started trucking right after World War I. I drove some of his old trucks with 220 cummins and it was 2nd and 3rd gear up the hill and sometimes 1st down the hill. If you're going slow enough the brakes take a lot less abuse,but it still doesn't negate the laws of physics .For every action there is an equal and opposite reaction. When you release the brake the vehicle speed increases ,when you reapply you just increased the load factor or workload of the braking system. It isn't exponential but it is significant. Incidentally I accidentally entered my profile information incorrectly. It should say experience 56 years not 36. I started in 1957. I bought a new Peterbilt in 1974 and the owners manual suggested the snub braking technique,but I knew from hauling heavy loads of coal in the mountains from the age of 15 that wouldn't work. Since then I dare say my trucks have been in the shop for brake shoe and drum replacement less than any on the highway,but like I said whatever works.

 

The CDL manual is chock full of misleading information. For example,back in the day our trucks had a switch on the dash that said "wet road /dry road. In the wet road position air pressure was reduced to the front brakes,and later on we began just unhooking the front brakes all together until the laws required them to be functioning. The manual says that front braking is ideal in all road conditions (not an exact quote) Back then I talked to those old Canadian drivers that ran the entire length and breath of Canada never seeing a dry surface ,and they all avoided those front brakes like the plague. Like I have said before manuals instructions and real world conditions are two different animals. When in Rome etc etc

 

Well I agree with Both of you Snubbing Works and so does Fendermans method, mine works too Just look we are here talking about it...
I simply was taught if you make it to the top in 9th drop the box to 6th slow and steady control to the bottom if she gets over 1600 slow steady pressure drop one more... I was taught in a 68 model mack, duplex tranny pulling grain from Southeast Virginia up over Afton Mtn on the back roads, we ran up to Moorfield WV we could not get on the Interstate due to 5% overweight and then some..
Driving out west for a while depending on the pass and the conditions with a newer truck I would use either way snubbing, going slow as all get out, or slow steady pressure, I learned from you older and much wiser guys "you can go down it a millions times slow and in control, you only come down it once fast and out of control"


and on the CDL examines, and books, well they are put out by a State agency most likely written by someone who has never driven anything bigger than a pickup.

 

Bingo exactly

 

When going downgrade on snow without chains, do not snub. If you are following a driver who chained up, leave plenty of following distance because he may snub.

 

Since this is the new driver's section, I will post this for those that have not as yet taken the CDL written test. The only braking method that is described in the mountain driving section of the commercial driver's manual is Snub Braking. The written test is based on information in that commercial driver's manual. You are all but guaranteed to get at least one question about braking while descending a steep mountain grade. The correct answer is Snub braking or the definition of snub braking. Light steady pressure will be offered as a possible answer because it is the old, out dated method. Light steady pressure is a WRONG answer on the written test. Any emergency braking technique [stab and/or controlled braking] is also a wrong answer.
.
.When a student goes for his driving exam, some time after the pre-trip, the examiner will ask them how to decend a steep grade. If you cannot correctly answer this question you will fail. No skills test. No road test. You are done for the day. Come back and re-test another day. And yes, the steps for descending a steep grade are spelled out in step-by-step detail in the commercial driver's manual. You can download the Cdl manual here:www.nj.gov/mvc/pdf/Commercial/CDL_Manual_english.pdf
.
.Remember, when descending a steep grade, your primary control over your speed is the engine braking effect. Jakes and using your brakes are only a supplement to that engine braking effect. If you have to use your brakes alot, you are in to high a gear. Do not attempt to shift while you are going down the steep part of the grade. If you miss the shift, your rate of acceleration will all but make it impossible to get it into any gear. And then you are screwed.
.

.For those who were taught light steady pressure, I am NOT saying that light steady pressure does not work. It does. However, it is not the currently approved and accepted method. Snub braking is the appropriate answer for the written and driving test. For a reference on Snub braking try here:
http://www.digitalmagazinetechnology.com/a/?KEY=truckersnews-09-11november#page=33

 

Right answer, wrong reason. If one or two brakes are tighter than others it creates a torque imbalance which is not appreciably affected by snubbing. With the higher application pressures of snubbing, the tighter brakes will still be applying harder with snubbing and still be appreciably hotter than the others. Snubbing helps counter a pneumatic imbalance, not mechanical or torque imbalances. The correct answer on the exam is as you stated "snubbing", but primarily for the aforementioned reason.
The 1993 manual change was primarily due to the March 1992 University of Michigan Transportation Research Institute Study.

Best regards

 

Sorry when you say "front brakes" you're referring to only using the trolley brake and not at all on the tractor?

 

He's referring to steering axle brakes....if I'm not mistaken.