Driving in mountains?

There are some exceptions that come with experience, but your better off to full jake in 8th or 9th at 40mph than trying to downshift, missing your gap and being runaway johnny...

 

Go slow very slow with 4 ways on. You have no experience driving mountains.

 

Going uphill, with practice, you should be able to instantly downshift without losing any momentum over the the minuscule deceleration you may already be undergoing.

Going downhill, you need to learn how to downshift accordingly to keep up with changes in decent rates or conditions. You may find yourself too fast or the grade may increase, or traffic flow ahead may slow. Going down a grade at a "safe speed" but in too high a gear is never advisable. You should always keep your RPM's above 1,300 ... preferably higher still. But soft-braking from 2,000 to 1,400 is okay (in the same gear) as long as minimal air PSI is required to slow that much. Low[er] RPMS provide little if any natural engine braking (engine brakes or not)

Ideally, with an engine brake [or not], you should (could) descend at a speed/gear that requires NO braking, but this is not practical in many shorter grade situations. Where this speed/gear combination is all depends on the grade, weight, aerodynamic efficiency, engine brake efficiency (horsepower and compression), and other environmental conditions. Even strong head and tail winds and air densities that change with altitude can have minor affects on your ideal speed on a given grade/weight combination.

 

I'll bite.

Let's start upgrade school.

You hit it at highway speed. Say... Mount Eagle GA/TN line Eastbound. I think it's 6% more or less. You will stay in your top gear until your engine bleeds from your 65 mph cruise speed at 1550 rpm (500 detriot) until around 1250 Rpm. For you it's 1300 RPM because you are inexperienced. You downshift one gear. Apply power. WHen the engine gets back close to 1300 or so, down shift again. You are no where done with Mount Eagle.

At some point upgrade you are going to settle at a certain speed somewhere between 1300 RPM, 1550 maybe 6th on a rockwell 9 short at about 38 or so. You are not even halfway up yet.

Check your Pyro if you have one, keep a eye on it. Make sure your temperature does not exceed 900 during your pull at any time. If it does (Safety margin, you can cook it at 1400 for a few minutes only but only if you need to. Regular driving you dont ever need to) down shift and back off your engine rpm redline and settle at 1600 rpm and bring that pyro down below 900. Ease back on the hammer towards 1300 as needed to keep it cool.

IF you don't have a pyro forget it.

Coolant is another problem, your engine oil temperature needs an eye on too. Usually it rises prior to your coolant water temperature. When both start to rise, you are abusing your truck, downshift again and ease off that rpm red line. You are seeking a upgrade balance of foward motion with about engine sweet spot that maintains your speed loaded without effort or overheating. Speed upgrade does not matter.

When coming over the top there should be a brake check station, get in there and stop. Pretrip your rig with a focus on defects along your brake pads, drums, airlines, air leaks, fuel leaks, problems inside your engine from the pull (Leave her running... she will be at work in a minute to the max... give it a chance to cool that turbo too. Never shut it off right after a pull. Cool that turbo down)

Basically go around and check all your tires too. And lugnuts. It takes about 20 minutes to go over everything. If there is a problem or something busted you will know then and there, not on the downgrade.

Then read carefully the information provided to you for the downgrade. I forget the percentages but you have two things. If you are loaded at 77000 to 80000 you start off at 10 to 15 mph from the top and stay in that speed. The other problem is that the bankment of the pavement itself will try to pull you either into the median rock cliff or off the mountain to the right. Your trailer will try to snake down the gravity you need to understand how to use your steering wheel to hold that trailer in line in your lane which means you will be steering somewhat off the mountain at times.

Start off at the green light and get your 12 mph or so on. Throw the jake on. Max. You should not have a problem holding 12 or so depending on what engine you got. Stay in that gear against your jake all the way down. You will be passed many times. Do not be tempted to run with them, you have no idea what is going on all the way down. It's a number of miles to the bottom.

Mount eagle is a small hill to me. But it's a easier mountain to learn rather than Donner which requires a larger post and is beyond you right now. Chances are you wont run Donner and others for a while.

In winter or in rain, your situation changes even more. You go even slower. Because your jake needs to work where a gear, jake downgrade gravity etc is all in balance to where your tach might vary a 100 rpm either way. that is good. What you don't want to do is go so slow your jake kills either the engine or causes your drives to stall and stop rotating on ice. This is summer time, winter is coming.

The old ones say you go down the hill in the gear you came up in. That is generally true. But many mountains require a seeking out of neutral forces against gravity, forward speed, weight and jake brake power.

Notice I have not said a #### thing about braking. If you do the mountain correctly, you will have cold brakes all the way to the bottom.

Im half tempted to get into the braking school... but fear that the forum's word count limit might kick in.

 

The old school rule of going down a mountain one gear lower than you climbed it has never failed me. Its not an absolute answer to all situations, but a good general guideline.

 

Maybe @scottied67 has a video for such things. He's our resident videographer.

 

They preach no downshifting downhill for new drivers because they might miss the gear and freefall down the mountain out of control. Practice downshifting on bunny hills before you get to the big hill.

 

My biggest fear is mountain driving

I did mount eagle about 2 weeks ago and obviously made it. I take all warning signs serious if I've never been on the stretch before.


With mount eagle I was about 78k and nervous as ####. The only reason I took that route is because it would have been day time and sunny when I got to it.

Obviously I made it but it wasn't perfect. I could smell my brakes by the time i made it but they weren't smoking.

If a sign says a certain speed. Think about your weight! I was not thinking about being that heavy, and trying to keep it at 45 in 9th lead me to applying brakes too much and speed rising. Didn't really have a stretch that I remember to try and down shift. But I stab braked my way down and didn't panic.

 

If you smell brake you lost the battle already thermal loading is gaining on you.

If you watched scottie's video and saw the Maersk seacan go by in hammer lane at the bottom, you see his brakes hazing prior to smoking.

Stab braking is rather wasteful on air.

What you want to try to do is apply about what? 9 pounds 12 pounds braking so that your brake is on constantly but not so heavy as to slow you quickly and not so light as to allow any increase in speed. You are trading thermal increase into airflow and also transferring heat onto the drums.

You can do that a while. But not too long.

What you really want to do is use enough brake to get it down 15 plus mph, downshifting two or three down, keep against your jake then wait a mile or two before doing that again. Hopefully at 80,000 somewhere near 20 mph and 4th gear low range you will have won the battle and can begin to cool your brakes all the way down.

45 in 9th loaded on that hill is too fast loaded.

Scottie must have been somewhat lighter and he made a smooth descent at 35-40 plus but jake was against his 1600 most of the way down so no problems. It's nice for me to look at that hill again but I myself have always been pretty conservative against mountains. It's how I managed them. It does not matter if it is 30% I'll get her down. You can hide in the sleeper a while eh?

There is a little tidbit for Scottie I can pick a bone, let her go at the bottom willya? Waiting all the way to the 70 sign he he he.

But that's me, I tend to use straight highways at bottom of certain mountains to allow a measure of run out I'll already be at 70 just prior to that sign. Let her go Scottie. Bright beautiful day, no traffic to speak of.

In my thinking Ive always had trucks to front, trucks behind, trucks to the middle and left and so on. Big herd all the way down.

if you want another mountain to cut teeth on, try "Black Mountain" it's 30 or less all the way down. There are sensors that will warn you to keep it under 30. I think that will be your next good one once you master Mount Eagle.