[TITLE: HOW TO BRAKE DOWNHILL SAFELY | AIR BRAKES SMART]
Hi there, Rick with Smart Drive Test talking to you today about downhill braking in an
airbrake equipped vehicle. Technology and air brakes in the last 30 years has
advanced to the point where air brakes are almost 100% bulletproof. There's very
few failings of an air brake equipped vehicle; however, brake fade and driver
error are the two weaknesses of the air brake equipped vehicle and just about
any braking system suffers from the weakness of brake fade if you hold the
brakes on long enough. So today, we're gonna talk to you about how to get down the
hill safely, the techniques that you can employ. Because if you don't and it gets away
from ya, hopefully you'll get it onto the runaway lane and bring it to a safe stop,
otherwise it's gonna careen out of control,
crash into a tree, and you're gonna die in a fiery inferno. So, we'll be right back to talk
to you about that.
[INTRO & MUSIC]
Hi there, Rick welcome back, talking to you today about downhill braking in a big commercial
vehicle. This applies mostly to buses, mostly to trucks, some RV drivers, and
people pulling RV trailers - heavier vehicles that need to get down the hill
safely. The first thing you need to understand is the grade signs. The grade
signs are listed in percentage of rise over run. For example, if it's a six
percent grade, that means that for every kilometre that you travel forward, the
hill is going to drop vertically 60 metres. The higher the percentage, the
steeper the grade. The next thing you need to know about grade signs is if the
grade sign is less than a kilometer, most of the time—and I say this with some
warning—most of the time it will not have a distance sign underneath it. So
there's no distance sign, it is less than a kilometer, however, I say that with some
caution because there are hills in British Columbia that have grade signs,
no distance signs, but they're far greater than 1 kilometer. So know the
hill, err on the side of caution if you don't know where you're going and having
been down that hill before.
We're standing here at the Hamilton Hill, 10 kilometers above
Merritt, BC. It's a six percent grade for 10 kilometers; 6 percent for those of you who don't
know, it drops sixty meters for every one kilometre you go forward.
Rise over run, six percent grade. It's a big hill, there's a big arrester bed at the
bottom for those trucks that might run away. In all the manuals it says to go down the
hill in one gear lower than what you went up the hill. That advice doesn't
work very well in British Columbia because many hills, you don't go up a
hill before you go down a hill. 13 or 18 speed, single-digit grade, 5th gear in a
tandem-tandem. If you're running heavier than a tandem-tandem, or you got dual digits, go
down into fourth, Jake brake on. Run the Jake between 15 and 1800.
Most trucks
today are 13 or 18 speed transmissions. Automatics are beginning to make some
inroads into the industry, but for the most part most of the trucks that you
will be driving are 13 or 18 speeds.
And I use this as a basis for teaching people how to drive down hill. So if your
driving tandem-tandem—two axles on the back of the truck, two axles on the
trailer, 13 or 18 speed, fifth gear low, on a less than 10 percent grade. Jake brake on
full and Jake brakes are designed to provide maximum braking capability at
high RPMs—between 15 and 1900 rpm. 5th gear low, Jake on high, tandem-tandem,
less than a 10 percent grade. The next heavier vehicle—anything heavier than
tandem-tandem, anything over 10% you probably want to be down in fourth, if
you're hauling Super 'B's at 63,500 kilograms, you're probably even wanna be
down into third. If you do the technique right, you got the Jake brake on, your in
the right gear, the Jake brake will hold the vehicle back all the way down the
hill and you will not have to use the brakes at all. However, if you're in a
gear and it's not quite right and it's not holding going down the hill and you
do have to apply the brakes, apply what is called snubbing. Run it up to 1,900,
hard, short, intermittent brake applications, bring it down to fourteen
fifteen hundred, let it run back up again—
hard, short, brake applications, let it run back up again.
In the introduction I talked
to you about brake fade... brake fade is the only weakness of not only an air brake
equipped vehicle, but every other type of vehicle - every other type of vehicle
equipped with brakes as well.
Brake fade is when you heat the brakes up too much. The drums expand away from the
shoes and the shoes will not come in contact with the drums and therefore you
do not have braking power. As well, if you heat them up too much, smoke, fire, and
leprechauns with marshmallows
chasing you down the road trying to have a weenie roast. So don't let the brakes
heat up! If you get in the right gear, you're going down the hill, you got your
Jake brake on, your not gonna heat the brakes up.
Talking to you today about safe downhill braking in a big truck.
We're above Merritt, 10 kilometers above Merritt, BC on the Hamilton Hill. It's a six percent
grade, it's a big hill. There's an arrester bed at the bottom for those trucks that
run away or lose their brakes for whatever reason. In this day and age, there's
is no reason to be losing your brakes. Technology, both air brake technology and
engine brake technology, are really awesome. If you get in the right gear to go
down the hill, you're gonna be set and you're gonna be fine. You won't even have
to use the brakes. The Jake brakes are very effective in holding the truck back
and holding it to go down hill.
[CLOSING CREDITS & MUSIC]
Something else I'm sure I needed to tell ya.
I guess I could look at my notes eh.
ohhhh...tandem-tandem, gear, brake fade, heavier, double-digits. less than one kilometre
distance underneath, yes!
Ya, I told ya all that!