Combined excerpts from previous posts of mine with a few edits / thoughts and clarifications, so it jumps around a bit.
I enjoy the "challenges" associated with mountain driving.
You have to enjoy being actively engaged and focused, managing your speed, rpm, looking at curve geometry, managing dynamic weight transfer, brakes and braking points; it's much like driving a race car / sports car at speed on a road course race track, but in slow motion.
You just have to take control and “actively” drive the coach yourself, use “tow/haul” mode, and no cruise control. In most cases going up steeper grades it’s easy enough to lock in at the 4250rpm range (it’s really noise control going uphill
) and then your speed is what it is; ocassionaly you'll end up in the next higher rpm brackets, but you’ll seldom have to run there for any length of time; it’s just up to you to control it with your right foot. You are not going to win any races, but you’ll get there.
At the extreme end of going down steep grades (something like the beginning of going down Wolf Creek Pass southbound) to start down and keep it in 1st gear which will hold until about 35mph, you’ll need to at about 15-20mph to start (you’ll feel the tranny drop to 1st) and you just have to realize it’s ok to be at 5000+ rpm as you descend and you are not damaging anything. As the revs start approaching 5500 rpm it’s time to get on the brakes so it doesn’t upshift, because you’ll quickly gain speed at that point; if it does upshift, you’ll need to really slow it down (not good) so it drops back down a gear. - try to learn that sweet spot before it upshifts.
It’s NOT about noise control going downhill, it’s about safety.
If you want to play with the shifter to select an initial gear, you can do that too and the engine / tranny will still not let you over rev the engine - it won’t down shift if it’s too fast for the gear, and it will still upshift at max rpms. I’ve played around with this, and it’s really not necessary unless for instance you want to force 1st gear at 25mph when it would automatically downshift at 15-20mph.
The key point on driving downgrades - start down slow, slower than what you may think; if the speed limit is 35, start at 20 for instance.
When having to use the brakes, and to minimize heat build up / maximize brake cooling, brake agressively, on them hard (and I mean HARD, real hard) then get off them immediately once you've reached your target speed. Yes you'll get some noticeable nose dive, and if you don't, you didn't brake hard enough. You do have to be cognizant of anyone closely following, so you might want to give a short tap on the brakes as a warning before jumping on them hard so as not to surprise the following driver.
The most important thing, bar none, is minimizing your time on the brakes so they do not overheat which can lead to brake failure. Braking hard and getting off ASAP at your target speed, whatever it is (be it 25, 35, or 65 mph) is your main objective as it maximizes cooling air flow over the pads and rotors. This has nothing to do with worrying about brake wear, it’s about not having brake failure. Forget about grandma spilling her cup of tea and “how to brake” from drivers ed.
As for how many mph you’ll gain before using the brakes, I’ve never really paid any attention and will say it varies. Going down a long straight downgrade is different than one with switchbacks. Probably somewhere between 10 and 15mph; 5 mph and you are probably on the brakes too much, more than 15 probably will cause an unwanted upshift. Again, less braking is better, but be safe..... start slow(er) and in a low(er) gear so that you have margin to gain speed.
On serious grades, even starting down at 15mph in 1st gear you will get to 4200rpm very quickly, and the ability of the engine to control your decent speed all the way to ~5500 rpm is key to staying off the brakes. The higher the rpm the better the engine controls your decent speed.
The tranny / ecu will not let the engine over rev., and the last thing I am worrying about is engine wear at high rpms.
If you don’t let the engine build revs to 5000+ on the type of grades I’m referring to, you’ll be on them constantly, and you could very well get yourself into a very serious situation with no brakes very quickly.
Even on more moderate downgrades there no reason not to let the engine do it’s thing and stay off the brakes. Again, be sure to approach a moderate grade at a slower intitial decent speed so that you can use the capability of the engine / tranny to control your speed.
Just another point to consider; brake in a straight line BEFORE the corner / switchback and slow enough for the tightest part the corner before you get to the corner; “trail braking" through a corner in a large RV isn't a good idea........
Some of the roads with significant grades we have taken in our gasser (~22,600#s fully loaded) always pulling the toad (~4,500#s) include:
I40 over the Smokies in both directions
I77 over Fancy Gap in in VA both directions
Both of which are “introduction mountain driving”
And then there are the “real mountains”:
I70 eastbound in eastern UT
Vail Pass eastbound
CO9 southbound from Breckinridge
Up and down to Estes Park
UT12 Bryce to Torrey
Wolf Creek Pass southbound
CO149 / Slumgullion Pass southbound
https://en.m.wikipedia.org/wiki/Slumgullion_Pass
Slumgullion Pass, elevation 11,530 ft (3,510 m), is a mountain pass in Colorado traversed by State Highway 149 east of Lake City. The north side has the steepest grade of any continuously paved road in Colorado (9%)
As well as some some fun grades in Quebec along the St. Lawrence, and across New Brunswick.
We’ll be heading back to the Rockies and west coast this coming summer....
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