Are there steep grades from Denver to San Francisco, to o dangerous for a 40 foot Tiffin bus with tow. How are the grades from in and around Alaska? How are the grades from Alaska to Yellowstone National Park?

Answering "can I safely drive this road" is always a tough question.It depends on TWO things:1. The equipment-- assuming it is properly maintained, likely not a problem.2. AND MORE IMPORTANT-- the driver. Mountain driving in a heavy vehicle is very different than in a car. It does have a learning curve to it and the speed with which it is learned depends to a large extent on how well you "feel" the machinery. Knowing what gear and use of engine brake by looking at a grade is a LEARNED thing. Knowing when you have pulled a long steep grade and KNOW that you will need to gear down to avoid overheating is a LEARNED thing.We have all gone through the learning curve (unless we only drive flat lands), but it is best to start out on the "bunny slope", not the black slope.

Hard to pass Sierra without hitting some grades, but it is westbound I80 coming down to Salt Lake City, where I have computer showing 99.9 mpg while doing 80 mph (in the car)The 10 miles grade takes pushing the brake to stay below 80 mph. Just make sure your cooling system is performing. I did the 12,000 + ft elevation in Colorado in Bounder with 454 engine. Not without vapor lock from overheat, but I made it.

Your profile isn't complete so we don't know exactly what you're driving, but I'm going to make the assumption that a 40' Tiffin has air brakes and a supplemental braking system (and you know how to use it). So as long as you use some common sense, you won't have any problem. I've been over those roads and you'll see hundreds of other MHs on them.You should buy the Mountain Directory which goes state by state, highway by highway listing any road grades or sharp corners (for speed considerations) that you should be aware of. It's divided into two books for either eastern or western states.Mountain Directories Bill

Trackrig wrote:Mountain Directories ^^this

That reminds me times before GPS, when in Colorado I was considering one of the mountain highways with my then 40'. I went to Ranger Station and ask about recommendations and female Ranger said"you should be fine as gravel trucks drive there all the time. There are no railings on side of the road, but that is good thing, becouse you might hit them with your motorhome on sharp turns"SHE WAS RIGHT.

Steep grades | Good Sam Community

robertbenita
Explorer
Jul 05, 2015
Beartooth Highway is a blast and only 6% I think. Our gasser at the time made it, but slowly. Our RV now did not have an issue! Good luck with your trip!
2gypsies1
Explorer III
Jul 04, 2015
Passin Thru wrote:
No grade is over 9% these days on any interstate.

I would say more like 6% and a few with 7%.
Skid_Row_Joe
Explorer
Jul 04, 2015
2gypsies wrote:
If you stay on interstates then you don't need the 'Mountain Directory'. However, there are many secondary mountain highways that a pick up truck could go but an RV is not advised to do so. You don't want to get going on one of those roads and not be able to turn around.

Now, if you're talking about a semi-truck then, yes, if a semi can do it a RV can, too.

We love mountain driving and have done a lot of it but we've also taken our towed car on some roads that we would never take our RV. Common sense.

Not all trips are 100% possible on the Interstate highway system. Having the directory lets me travel where I want to, which is why I bought the RV.
dubdub07
Explorer
Jul 04, 2015
You coach is fine. You will have no issues on I-70 or I-80.
Skid_Row_Joe
Explorer
Jul 03, 2015
Trackrig wrote:
John S. wrote:
So, why do you need a book. The signs tell you as does looking out the window. If it is a main road or interstate and can handle a truck, it can handle a coach.

Drivers that are new to mountain driving are a lot more comfortable if they know what to expect about the road before they get there. As for trucks, I've had my DP on many roads where trucks don't go such as lower Utah and coming into the Tetons from St Anthony. You can't get part way into those roads, see no trucks, and decide to turn around.

Where is it, I believe south of Mt Rushmore, on a road called Iron Mountain Road and then the one that goes up to Needles. I believe the book will tell you not to take anything over 30' (maybe shorter) on those two due the very sharp blind turns on a narrow road. From the amount of scrape marks on the rock besides the road, people must not have read the book. And 13' high MH wouldn't have fit through the tunnels either. The Jeep did just fine.

Just because I go into some areas doesn't mean the next person should or would. And I wouldn't have gone into them if I didn't have air brakes and a retarder.

Forewarned is Forearmed.

Bill
X 2
Exactly right.

Why some don't want others to have these directories is a hard one to understand when it comes to planning your trip. A big rig is a big responsibility out on the open highways.
luvlabs
Explorer
Jun 28, 2015
Your Allegro Bus is equipped with everything you need to climb and descend mountains safely - as long as you use it properly. Your Allison transmission has six speeds and you should learn to downshift to keep the engine in its power band (around 2000 rpm) when climbing grades. Your engine and transmission will run cooler and you won't be setting any speed records (you really don't need to climb the mountain at 55 mph, 45 or less is fine).

When descending a grade, use your exhaust brake before you use your foot brakes. You have a 2 speed brake - try it out before you jump into the mountains. The trick is to descend a steep mountain in the same gear and same speed as you went up it. If you do need to brake, apply your brakes hard enough and long enough to snub your speed down to below the speed you wanted to descend at - and then take you foot off the brake and let the transmission and exhaust brake do their jobs. This allows the brakes to cool between applications. Do not ride the brakes as you will overheat them and posssibly lose your braking.

Want some practice - take a drive to Smokies and points north. My favorite "western type" climb and descent is I-77 at the NC, VA border. The area is called Fancy Gap and you have 6-7 miles of grade into VA and, of coarse, 6-7 miles of down hill back into NC.
Passin_Thru
Explorer
Jun 28, 2015
No grade is over 9% these days on any interstate.
2gypsies1
Explorer III
Jun 28, 2015
If you stay on interstates then you don't need the 'Mountain Directory'. However, there are many secondary mountain highways that a pick up truck could go but an RV is not advised to do so. You don't want to get going on one of those roads and not be able to turn around.

Now, if you're talking about a semi-truck then, yes, if a semi can do it a RV can, too.

We love mountain driving and have done a lot of it but we've also taken our towed car on some roads that we would never take our RV. Common sense.
ncrowley
Explorer II
Jun 27, 2015
I second getting the Mountain Directory West. It is very detailed and tells you what to expect on each road. You can then decide what route you want to take.
Trackrig
Explorer II
Jun 27, 2015
John S. wrote:
So, why do you need a book. The signs tell you as does looking out the window. If it is a main road or interstate and can handle a truck, it can handle a coach.

Drivers that are new to mountain driving are a lot more comfortable if they know what to expect about the road before they get there. As for trucks, I've had my DP on many roads where trucks don't go such as lower Utah and coming into the Tetons from St Anthony. You can't get part way into those roads, see no trucks, and decide to turn around.

Where is it, I believe south of Mt Rushmore, on a road called Iron Mountain Road and then the one that goes up to Needles. I believe the book will tell you not to take anything over 30' (maybe shorter) on those two due the very sharp blind turns on a narrow road. From the amount of scrape marks on the rock besides the road, people must not have read the book. And 13' high MH wouldn't have fit through the tunnels either. The Jeep did just fine.

Just because I go into some areas doesn't mean the next person should or would. And I wouldn't have gone into them if I didn't have air brakes and a retarder.

Forewarned is Forearmed.

Bill