RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 05-20-2017, 11:56 AM   #1
MVP
Member
 
MVP's Avatar
 
Join Date: Dec 2016
Location: Solano County, CA
Posts: 92
Driving Over Passes

Need some tips.

Next month I'm driving our new 38' diesel pusher on highway 80 over the Sierra pass. There are long 5-6% grades. I've read to leave my compression brake on and drop it to 3rd gear and just let ride at about 45 mph, and when breaking, stab the pedal vs riding the breaks.

Does that sound right to everyone? Looking for more tips. Thanks folks!!
MVP is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 05-20-2017, 12:00 PM   #2
Senior Member
 
Mr_D's Avatar
 
Country Coach Owners Club
Winnebago Owners Club
Solo Rvers Club
iRV2 No Limits Club
Join Date: May 2011
Location: Vancouver, WA
Posts: 37,083
Seems about right, although you may have to use the up and down buttons to get the right gear to be in "equilibrium" and not need to stab the brakes, plus it depends on what gear the transmission is programmed to seek. My ISC with Allison 3000 in the '02 DSDP was programmed to preselect 2nd but it only had the exhaust brake. The present rig preselects 3rd but I have a 3 stage engine brake and very, very seldom do I need the "high" setting.
__________________
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft, HWH Active Air
Charter Good Sam Lifetime Member, FMCA, SKP
RV'ing since 1957, NRA Benefactor Life, towing '14 Jeep JKU Dragon Edition
Mr_D is offline   Reply With Quote
Old 05-20-2017, 12:16 PM   #3
Senior Member
 
Tiffin Owners Club
Appalachian Campers
Mid Atlantic Campers
Coastal Campers
Freightliner Owners Club
Join Date: Jan 2015
Posts: 1,615
If you want to be technical about it.......

You can calculate the maximum speed in any gear.
- Your engine manufacturer will give you the max rpm parameters, before it will upshift to protect the engine.
- Your transmission mfg will give you the gear ratios, I called mine and that took just a couple minutes
- Your chassis manufacturer will give you the rear end pumpkin ratio
- The tire mfg specs will give you the diameter of your tire, and you can verify by wrapping a string around.

A quick little spreadsheet then will give you the max mph for each gear, before it'll upshift. Then you'll know what speed you need to stay under, to enable your current gear selection to stick.

Your spreadsheet can easily do it for all 6 gears, but 3rd and 4th are really the ones you'll be focusing on. Also, calc it for 2000 rpm, and also your max engine rpm.

Then you can compare how your coach really performs, compared to your calculated values.

Although you may be running your genny and the house A/C going up the hill, you can also consider turning on your dash A/C coming down to strip off another 20 ish HP.

Definitely don't ride the brakes, if you start creeping up to getting close to the shift point, smooth hard braking to drop your speed back down and get off the brakes so they can cool. You don't want it to rise over the mph where it upshifts, because then you'll loose the engine/exhaust braking effect you had and have to slow it a lot with the service brakes to get the speed back down.

There are some mountain pass books you can purchase (east and west), which give you information about the grades so you can plan long before you get there. Search around though on the internet, wide variances in pricing.

Assuming you have a Cummins, if you google Cummins engine parameters, then find your engine, that'll give you some of the info that may be helpful.
__________________
DaveB, Raleigh, NC
2015 Tiffin RED 33AA, w/Honda CRV
VMSpc, Magnum BMK/ARC50
Kiawah is offline   Reply With Quote
Old 05-20-2017, 12:23 PM   #4
Senior Member
 
Join Date: Apr 2017
Posts: 199
>"Next month I'm driving our new 38' diesel pusher on highway 80 over the Sierra pass. There are long 5-6% grades..."

Did that awhile ago, (5th wheel). Modern RAM diesel pickup with engine brake on... in the appropriate gear... you don't need to touch the brakes much at all.

I suspect your diesel will be the same way.
Twilightzone is offline   Reply With Quote
Old 05-20-2017, 12:34 PM   #5
Senior Member
 
Join Date: Jan 2015
Location: Oroville, CA
Posts: 3,133
When going down a hill, use the same gear that you used to get you up the hill.

Donner Pass (hwy 80) is not bad, long downgrades, yes; the biggest consideration is the amount of traffic- Trucks in the right lane will be plodding along at 15-20 mph on the uphill, then 60+ on the downhill. I stay out of the right lane on the uphill and just maintain my speed (45). On the downhill, just stay in your lane and let 'em pass (watch your right mirror for passing traffic).

80 east of Truckee has fewer lanes and some turns that may surprise you. Watch your speed as it may creep up on you, especially once you pass the (westbound) ag inspection station. Kinda curvy 'till you get to Bordertown.
In Reno, know where you are going (395 N or S) or 80 East and watch for merging traffic. You are bigger than most, but lotsa traffic. Stop at the exit for Fernley for fuel/food. Stop in Elko at the California Trail museum-fantastic!California Trail Interpretive Center | Elko, NV
__________________
Bill, Kathi and Zorro; '05 Beaver Patriot Thunder
2012 Sunnybrook Harmony 21FBS (SQEZINN)
2007 Jeep Grand Cherokee Overland
cruzbill is offline   Reply With Quote
Old 05-20-2017, 03:54 PM   #6
Senior Member
 
Ludmilla's Avatar
 
Join Date: Jun 2015
Posts: 558
Go slow enough so your exhaust or engine brake will keep you at a steady speed. Use the brake to get you to that speed and then you should not have to use the brakes to keep your speed down.
Ludmilla is offline   Reply With Quote
Old 05-20-2017, 05:46 PM   #7
Bug
Member
 
Join Date: May 2017
Posts: 82
While I am totally new to RV'ing I'm a veteran at Donner. Don't worry about Donner Pass. It's really nothing too extreme. I drive a big rig over it all the time. Sun and snow. Nothing to be intimidated about.

The east to west is a gradual decline down the mountain that lasts for miles. The west to east direction is more of a drastic drop but still pretty mellow.

I assume your DP has a Jake Brake. "Compression brake".

I have never driven a dp motorhome however I assume it's similar to a rig.

There's all sorts of strategys to handle a mountain. Personally. I turn on the Jake. Grab a gear and see if it holds.

Seeing you're in Fairfield I assume you're heading towards Reno. Climb the long hill and up by Boreal you will reach the peak. There's a rest stop up there as well if you need a break.

Round the mountain. Turn on the Jake. Maybe drop a gear or so and see how it holds. Do you pick up speed quickly or slowly. Are you comfortable with the speed. If not. Brake a bit and go a gear lower. Again check how fast you're gaining speed and are you comfortable.

As for the breaking. Stab breaking is not necessary. Just don't ride the breaks and let them off and ride them again. Heat can become an issue but if your Jake braking and not barreling over or letting yourself get crazy it shouldn't be a problem.

The thoughts behind stab is that you are hard breaking for a short time and then letting off. Therefore it's less friction time on the brakes/rotors. However if you have your speed controlled by the Jake and gears you shouldn't have to brake hard or much to control your speed.

If it's your first time doing this then maybe work upwards instead of down. Meaning. Lowest gear and Jake and shift up to find the right gear/Jake/brake ratio for your setup.

Halfway down the hill it will turn kinda right and level out or go upwards a bit. This is a good time to just let it ride. No need to brake then it will start down again.

Don't get all psyched out. It's nothing. There's also no need to crawl down the hill at 35. You can safely navigate in the 50/55 area so long as you're comfortable with your speed gains.
__________________
2007 Fleetwood Flair 33r
33 feet, 2 slides, I assume everything is stock. It's an ex rental unit.
Bug is offline   Reply With Quote
Old 05-20-2017, 06:12 PM   #8
Senior Member
 
Join Date: Jan 2015
Location: Oroville, CA
Posts: 3,133
I believe the OP has a Cummins ISB 6.7-no compression brake, as I understand it, the engine brake is via a variable gate turbo (VGT). Don't know how this brake setup compares with a 2 or 3 stage compression (jake) brake.
__________________
Bill, Kathi and Zorro; '05 Beaver Patriot Thunder
2012 Sunnybrook Harmony 21FBS (SQEZINN)
2007 Jeep Grand Cherokee Overland
cruzbill is offline   Reply With Quote
Old 05-20-2017, 10:06 PM   #9
Senior Member
 
Hmf23's Avatar
 
Join Date: Jul 2015
Location: Elk Grove, Ca
Posts: 264
As a driving instructor for the Fire Department here in Sacramento we teach a lot in this subject. We instruct all our new drivers when on probation and continued instruction with veteran drivers. Knowing your engine rpm parameters is very key as stated above, remember the maximum amount of retarding power is at 90% of maximum rpm's. We teach a lot with vehicles that don't have compression engine brakes, so we emphasize the use of lower gears when necessary along with a braking tecnihue to help slow the vehicle while not over heating the brakes. It was stated to go down the hill in the gear you went up, well you can also use one less. This will start you down with higher rpm and slower speed, if it's too slow you can up shift as needed. we also teach a 5x5 braking technique. Let me explain: using max posted mph as your hit that speed you make a firm aggressive brake application and your looking for a 5 mph reduction over a 5 second application of the brakes. Then you let off and let the speed pick back up again to max and repeat as many times as needed. Good luck, we plan on that same route in sept when we return with our new Newmar Mountain Aire.
Hmf23 is offline   Reply With Quote
Old 05-21-2017, 08:10 AM   #10
Senior Member
 
J Birder's Avatar
 
Join Date: Feb 2012
Location: Lake County, IL
Posts: 1,412
Quote:
Originally Posted by cruzbill View Post
When going down a hill, use the same gear that you used to get you up the hill.
I see this stated all the time, but really is not good advice, There many passes that are very steep on one side, but extremely steep on the other side. Besides, how many people with automatic transmissions even know what gear they were in going up?

A typical example is in the Bighorn range in Wyoming. Going westbound, up U.S. 14, I can do most of the climb in 4th gear, only occasionally dropping into 3rd.

Going down on U.S. 14A, I do most of the descent in 3rd, occasionally dropping down to 2nd.

Joel
Attached Thumbnails
Click image for larger version

Name:	14a.jpg
Views:	77
Size:	82.9 KB
ID:	162521  
__________________
Retired electronics engineer. Avid paddler & birder.
2011 Silverado 2500HD, diesel, 4x4,crew cab, 8' bed
Palomino Puma 253FBS (27' 5er) & '94 19' Class B
J Birder is offline   Reply With Quote
Old 05-21-2017, 09:02 AM   #11
Senior Member
 
OLYLEN's Avatar
 
Monaco Owners Club
Join Date: Jan 2008
Location: Olympia, Wa
Posts: 2,771
At 5-6% the exhaust brake maybe too much so you may need to turn it of and on with like third gear setting, when the brake is on the trans may shift to 2nd as it slows, then turn the brake off then back on as needed. On the climb get ahead of the hill by dropping to say 4th gear or 3rd as needed, only experience will tell. Also if you are slowed pick a gear to hold the motor to your best cooling RPM and just ride it out. Oh and look at the manual on your motor, on many the red line is above the the power red line with exhaust brake on. The trans is built to take care of itself so if you get out of safety parameters in will shift up. But as I say the 5-6% grades should not be a problem.

LEN
__________________
2004 Clss C 31' Winnebgo
OLYLEN is offline   Reply With Quote
Old 05-21-2017, 09:13 AM   #12
Senior Member
 
Thor Owners Club
Join Date: Aug 2010
Location: Delaware
Posts: 602
A couple more thoughts:
- I don't get hung up on gear selection -- the computer coordinating the Cummins and Allison is much smarter about that than I am. When you flip on the engine (compression) or exhaust brake, whichever you have, it also automatically starts a downshifting algorithm, which I feel has a greater effect than the compression/exhaust braking itself.
- don't let your speed get over 55 or so; beyond that point your RPMs are getting too high to downshift.
- As stated above, don't ride your brakes, but Google "snub braking" vs. "stab braking" -- snub is really what you want.
__________________
Crabby Mike
2019 Coach House Platinum 261XL RT
towing 2016 Grand Cherokee Overland
Crabby Mike is offline   Reply With Quote
Old 05-21-2017, 09:27 AM   #13
Senior Member
 
jerichorick's Avatar
 
Winnebago Owners Club
Join Date: Jun 2013
Location: Full-timer/volunteer w/SOWERS
Posts: 3,749
Quote:
Originally Posted by MVP View Post
Need some tips.

Next month I'm driving our new 38' diesel pusher on highway 80 over the Sierra pass. There are long 5-6% grades. I've read to leave my compression brake on and drop it to 3rd gear and just let ride at about 45 mph, and when breaking, stab the pedal vs riding the breaks.

Does that sound right to everyone? Looking for more tips. Thanks folks!!
Went through the Grand Teton's last year. 10% grade up and down.

I NEVER shut off my compression break. Saves wear and tear on the service breaks. Most engine break restricted areas will never know it is in use because our coached don't rattle loudly from the exhaust when it engages.

Breaking is a learned art. You don't want to break hard. Ever. Apply the breaks just long enough to keep the speed down. Don't go much over 5mph above your desired speed before applying the breaks. Air breaks will loose pressure if applied too many times in a short distance. Steady, controlled breaking is the rule that works. Always be aware of overheating them. Pull over and stop if you suspect this is happening.

Downshifting is good to do but don't over tac the engine. Watch your gauges for over heating when going up hill. Down shift to increase RPM and to increase cooling.

Have a great trip.
__________________
Rick & Melissa Young, 2011 Itasca Meridian 40U, Frtliner XCL, Cummins ISL 380HP/DEF, Allison 3000 MH, 2014 Honda CR-V, SMI AF1, Blue Ox, EEZ TPMS, TruCenter steering control
Servants On Wheels Ever Ready. Best job we ever paid to do . (full time volunteers)
jerichorick is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
MB Sprinter over Colorado Passes? Old Dude 66 Sprinter Chassis Forum 5 12-11-2014 07:02 AM
Driving through mountain passes zzzgas Class C Motorhome Discussions 15 06-25-2013 12:22 PM
Good-To-Go passes / Tacoma Narrows Bridge Ceratto's Grotto Northwest Region 1 12-02-2008 08:22 AM
New National Park Passes Hoverbug iRV2.com General Discussion 7 02-05-2007 07:51 AM
Colorado mountain passes to avoid w/35' Class A Gas MH w/toad ??? RTZ6885 Winnebago Industries Owner's Forum 4 01-31-2005 08:12 PM


All times are GMT -6. The time now is 06:17 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.