braking on big mountains...

The first truck driving job I had was with JB Hunt. I doubt that means anything to you because you are so new. FYI the International cabovers JB ordered back then did not have any kind of engine brake. Low horsepower Cummins engines with 7 and 9 speed transmissions were what we had to drive.

I spent 6.5 years there and racked up over 750,000 miles traveling all over this country and NEVER had any kind of engine brake.

I am still out here. Have never had a brake failure because "Snub braking" does work. If you do over heat your brakes while using this method then you are doing it WRONG.

The same goes for the old method of light steady pressure. Too bad most fleet trucks do not have an air application gauge so the driver has no idea how much pressure he is actually using.

Fortunately EVERY truck does have a speedometer and therefore it is much easier to monitor the vehicles speed.

I have seen many trucks descend mountain grades too quickly over the years. The smoke shows I have seen have been from drivers traveling too fast to begin with and then riding their brakes all the way down. I have seen very few smoke shows as a result of drivers braking and then releasing periodically.

Again this is is where my "experience" and observations far outweigh the time you have accrued behind the wheel of a truck.

 

I wish more students would be taught snub braking. I'm amazed at how many don't know how to do it properly.

 

Perhaps a big reason for smoked brakes is uneven brake application. Even if your brakes are adjusted within the legal limit, they are not necessarily all applying the same amount of force to the drums. When I adjust my brakes, rather than measure pushrod travel, I tighten the shoes to the drums then I slowly back them off while sounding the drum with a hammer. The instant the drum rings like a bell, thats when its adjusted. When I adjust one brake, I adjust them all. When all your brakes apply the same pressure, you are less likely to smoke them regardless of which of the descent methods you use.

 

A valid point. On many mountains there are pull off areas at the top for drivers to adjust their brakes prior to descending. I doubt many of the newbies even carry tools let alone have the training to adjust them correctly though. Of course most of the trucks and trailers today have automatic slack adjusters and are not "supposed" to be manually adjusted.

Its been many years since I have traveled through the Rocky mountains but I do seem to recall many of the passes out west not only had pull off areas before the descent but also had diagrams of the roadway with run away truck ramps depicted as well as recommended speeds for the descent based on the weight of your vehicle. This info is very valuable and helpful to beginners and veterans alike.

 

The problem with dragging your brakes down a hill is exactly that. If your brakes are unevenly adjusted, the ones that are adjusted tighter will be doing all of the work and not be allowed to cool down. Those drums will expand and become less effective. Snub braking, when done properly, forces all the brakes to work, at least partially. If you are in the proper gear when you start down the hill, you should have about 2 to 3 seconds of braking and 10 seconds of cooling off at 5 to 10 mph above and below the speed limit. Its the method I've used for 13 years and I've never had a problem.

 

primexample,

I understand your desire to try and inform drivers as well as teach others. It is time to expand your knowledge (and hopefully understanding); I would like you to take some time and google the following term; "snub braking."

The very first entry should be from John C Glenn. Please read the article and try to comprehend what he has written.

I believe that should clear up your "misconceptions" about snub braking.

Here is an excerpt from that published article;

When the Commercial Drivers License (CDL) manual was first published, it recommended that a driver use a light and steady application of the brakes when descending steep grades. This recommendation was based on an old theory that heavy brake applications would generate more heat than light applications. This method (controlled braking) was commonly taught to drivers and, even after changes were made to the CDL manual because this theory was proven wrong, the method is still taught and practiced today.

Snub braking is now the recommended method of downhill braking. This method works by: first, choosing the correct gear for the hill; second, allowing the truck to speed up to the maximum safe speed as it descends the hill; third, applying the brakes hard to slow the truck down 5 mph; and then repeating this process to the bottom of the hill.....

To read the rest you will need to go to the website.

Still not convinced? try reading the article from ez.net the link is entitled; " down hill braking, truck accidents, air brakes, runaway accidents" and the article is DOWNHILL BRAKING "snub don't ride"

 

We had a very long lecture and video on this in my class at Fox Valley Technical College. I don't know what other schools teach.

 

I agree with using snub braking, I haven't smoked my brakes yet. I don't run up to the max safe speed though. Staying 5mph under that makes a huge difference. 5-6% is easysauce, 8% is where the fun begins.

 

I am kinda used to this difference of opinion. The school I went to in 1991 was actually a very progressive school and one of the first ones to teach snub braking to new drivers.

It is difficult to teach some older drivers a new technique when they have used their method for decades. Unfortunately there are still some schools that are not up to speed on the current methods or even technologies available in modern trucks.

My only desire in posting at this forum is to relay my experiences, and knowledge to other drivers that are interested in learning. Of course we (the posters) will not always agree but at least we can offer our perspectives and allow the readers to come to their own conclusions based on the information offered.

Now that I have offered additional sources from "experts" rather than just my "opinion" regarding braking on mountains I hope we can put this issue to bed.

 

well if the cdl booklet were wrong about controlled braking at first. what makes you think they are right about snub braking now????????????