Hills/mountain descending?

Most times you are going to go up a 6% grade in 7th or 8th gear. Leave it in that gear when going down. Depending on weather conditions and how good your jake brake is. You shouldn't never have to touch your brakes. If It is icy then gear down lower. I have always used my jake in winter time in snow and had no problems. I'm always prepared to turn it off it I go into a skid. Always be aware of the road conditions. If roads are that bad shut down and try when roads are safer to drive.

 

I'm not familiar with the grade you are talking about but here's my 2 cents. The book when it talks about "go down a or 2 gear than you went up." is wrong and here's why......Trucks today have a lot more power than those of yesterday when this was probably written. You can probably climb the grade in 7th gear depending so you're not going to go down in 5th at a mere 15 or 20 MPH.. so here's how I run a grade let's say here in AZ. Pay no attention to the speed limit since it was put there for cars. Just because it says 65 or 75 doesn't mean you should be doing it. Descending into Camp Verde on I-17 in AZ is I believe a posted 55MPh. I'll run about 45 to 50 down the hill. This is with a loaded tanker though so I'm a little more careful. I'll probably run 8th gear (standard 10 speed) with the jake on and the RPM's around 1850 to 1900. Almost never have to touch the brakes but when I do I go off what the book says....."select a safe speed and when you reach it brake until you drop your speed to 5mph less than your selected safe speed." I'm never afraid to put on my four ways going down the hill if I'm moving a lot slower than everyone else. If I'm empty on the other hand........it's game on and I'll run what the speed limit says. Remember that the service brake is only a supplement to the braking effect of the engine. The engine is your primary brake! That means select the proper gear before going down the hill. If you select the proper gear before going down the hill and use the braking technique the book teaches you should have no problems. As far as inclement weather I will use the jake brake any day before I step on the service brake. Ok so I can see it now...............Here comes all the "rooster Cruisers" with their advice on how to get down a hill safely..........Just remember, you'll only go down a mountain tooooo fast one time...

 

Don't worry about traffic around you including other truckers. If you need to go down extremely slow because that is safe for you then do it. I sure do and I don't care what others think. I have a family to go home to and that's all I care about. If you don't go down too fast then you won't have to worry about burning the brakes. The brakes are meant to be able to stop you completely even on a downgrade if that was necessary. Remember the engine brake is secondary to your service brakes.

 

Wrong...The service brakes are secondary to the braking effect of the engine. If you use your service brakes (the foot pedal) as primary braking you will someday lose them.

 

What braking effect of the engine? Do you mean the Jake brake or the transmission gearing? Anyway the service brakes are primary over the jake/engine brake as I stated in my reply.

 

No, the service brakes are not primary....Yes gear selection and engine braking (if the truck is equipped with one) is the primary way to brake going down a hill. Service brakes are only a supplement to the braking effect of the engine.

 

You need to get a feel for your truck and until you do, be over carefull.

Things to consider:
Grade, Steeper the grade the lower gear you should start in
Weight, 10,00 pount load isnt bad, 40,000 is.
Turns, are there turns you will need to be slower for
Weather, is there ice, snow or rain that you want to go slower for.


First off, lets tackle dry weather, no bad turns
If load is 10,000 or less, I wont drop until 6%. 6&7%=9th, 8&9%=8th 10&11%=7th etc.
If load is 30,000 or less I'll start 2% lower. any marking 9th, 6&7%=8th etc
If load is max weight, (upto 80k gross) I'll start down shifting earlier. Any sign is 8th. 6&7%=7th, 8%=6th, 9%=5th 10%=4th

Now these are just ball parks and you need to get used to how your truck jakes and how it slows. Aim for a target speed in the top of the rpm range for the gear your in. (maybe 1800 rpm, depending on engine) Turn your jake on max. Once you hit max rpm (depends on engine, but 1800 will be good for a cat, maybe evena nothe 200 rpm for detroit. Unknown for isx.) brake hard enough to drop 5 mph within 3 seconds. If you cant drop that speed in 3 seconds brake harder. DOnt ride the brakes or you will over heat them. wait for rpm to rise again to target speed and then drop 5 mph again. If the speed is rising to quick and you are loosing air to fast, you chose to high a gear. Don't change it now, but drop 10 mph each time you hit brake within 4 or 5 secs. If your dropping air to fast look for a runaway ramp. If you start to get brake fade (they start becoming less effective) brake harder for a shorter time. If it gets worse start looking for a runaway ramp. the engine does its best braking at high rpm, so dont be afraid to go there. use brakes to keep it form getting to high as mentioned above. I highly recommend you dont try an switch gears on a downhill, because if you fail your sol. the wrong gear is better then no gear.

Now for winter roads:
Start out in a much lower gear so you can use the engine to brake you instead of using jakes. I still use jakes in any situation but am careful. The only trick i go slllloowwwww. Select a gear you think you should be an and then shift in to 2 gears lower. ride down the hill at 10mph with your flashers on if you have to. try and go slow enough that you wont need to brake because on snow, an 18 wheel lock up is easy...and abs is a joke. If you do use brakes, pump them and use lightly. Most jakeknifes are do to trailer wheel lock up. If it happens get off brakes and accelerate slightly. This is why i use jake. There is know chance of lockign trailer wheels if im jaking just on my drives. That being said, i could loose grip on my drives, but i feel its less likly then if i use my brakes. A jake slows down your drive wheels, where braking could lock them up. Braking does give you 5 axles of brakes though where jaking only gives you 2. A healthy combination should get you down safely. key with snow and hills is SLOW SLOW SLOW!. Also dont do anything stupid. If you see a sheet of ice down a 15% grade no amount of going slow is going to grip that ice without chaines, or spikes.

 

I think we agree but maybe you misunderstood my first reply. Rated most important to least important
1-Transmission gearing
2-Service brakes
3-Jake/Engine brake