Best practice for steep downhill freeway grade - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 05-26-2019, 02:08 PM   #1
Member
 
Name: Deborah
Trailer: Currently shopping
CA
Posts: 71
Best practice for steep downhill freeway grade

Although I've towed boats in the past, I'm new to towing a trailer. Next week I'll be practicing with my new tow vehicle and new to me Casita, and want to ask about a downhill freeway grade that will be part of most of my trips.

When I used to drive our old Class A RV down this grade, I would often shift out of "OD" into regular D, using the engine to brake the rig a little. My new Durango has regular drive, and then an option to shift into manual, which would then allow for a downshift. Which is better, to do that, or to use my brakes, thereby of course using my trailer brakes, even if I end up using them quite a bit while going down the grade?

I hope this question makes sense. I thought it would be good to ask for advice rather than start experimenting at 55 mph!
__________________

DebiT is offline   Reply With Quote
Old 05-26-2019, 03:04 PM   #2
Senior Member
 
Name: bill
Trailer: 2013 Escape 19; 1977 Trillium 1300
The Mountains of North Carolina
Posts: 2,594
Registry
I never use overdrive when towing, ever. My truck has a tow mode which automatically downshifts on down grades.

Read your owners manual and see what it says on using overdrive when towing.
__________________

thrifty bill is offline   Reply With Quote
Old 05-26-2019, 03:15 PM   #3
Member
 
Name: Deborah
Trailer: Currently shopping
CA
Posts: 71
Thanks. I'm understanding it better now.
DebiT is offline   Reply With Quote
Old 05-26-2019, 06:39 PM   #4
Senior Member
 
Jon in AZ's Avatar
 
Name: Jon
Trailer: 2008 Scamp 13 S1
Arizona
Posts: 8,494
Registry
Best practice for steep downhill freeway grade

You will definitely want engine braking, not friction braking only, on a long down grade. As said, read your manual regarding transmission use when towing. Most likely youíll use the manual mode and downshift as needed.

Best practices vary a lot with modern transmissions because much depend on the control software. Mine says to turn off OD on hills, but okay on flat terrain.
Jon in AZ is offline   Reply With Quote
Old 05-26-2019, 06:46 PM   #5
Member
 
Name: Deborah
Trailer: Currently shopping
CA
Posts: 71
I drove up to the Grapevine and practiced a bit, so now I feel a lot more comfortable. Next week get to take my Casita out driving around to practice towing and backingm. First trip not til 6/21 due to other family things.
DebiT is offline   Reply With Quote
Old 05-26-2019, 07:32 PM   #6
Junior Member
 
Name: bj
Trailer: Escape
California
Posts: 7
Whoa, the Grapevine is certainly steep practice.

It's a good idea to practice. I like to go to a big parking lot (mall? closed supermarket?) If you have cones they are good markers for backing up. Go slow, don't be afraid to get out and look what's happening as often as you need.

You got this.
bjshan is offline   Reply With Quote
Old 05-26-2019, 07:39 PM   #7
Senior Member
 
Name: Gordon
Trailer: 2015 Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 3,739
One of the reasons I chose a Toyota Sienna over a Honda Odyssey was that the Toyota has an auto-transmission that allows you to downshift. I use it to apply engine braking on downgrades when towing. The trick is to slow down so as to to exceed the limits of your brakes and tranny. The brakes will always engage but can overheat and then you get "brake fade." The tranny, on the other hand, will not shift if the engine RPMs exceed safe limits when you downshift, so keep it slow enough to allow the tranny to shift to lower gear and save the brakes from overuse. I guess those figures are available, but with a little practice I can judge it pretty well. If you do find your speed downhill increasing to the point that you have to stay on the brake pedal risking brake failure, and the tug's computer will not let you downshift, then hit the brakes firmly and quickly slow to a speed where you can downshift and let up on the brakes. The added engine braking should allow your brakes to cool and recover. Use both tools (tranny and brakes) to control your downhill speed.
gordon2 is offline   Reply With Quote
Old 05-26-2019, 07:52 PM   #8
Senior Member
 
floyd's Avatar
 
Name: Floyd
Trailer: 2004 13 ft Scamp Custom Deluxe
IllAnnoy
Posts: 7,441
Registry
Quote:
Originally Posted by thrifty bill View Post
I never use overdrive when towing, ever. My truck has a tow mode which automatically downshifts on down grades.

Read your owners manual and see what it says on using overdrive when towing.
My truck has 3 overdrive gears!
floyd is offline   Reply With Quote
Old 05-26-2019, 09:46 PM   #9
Member
 
Name: Deborah
Trailer: Currently shopping
CA
Posts: 71
Thanks all. Trailer practice is next weekend, need to find some cones. Will be having experienced person help me with initial set up of matching my TV and Casita up, and adjusting my brake controller
DebiT is offline   Reply With Quote
Old 05-27-2019, 06:43 AM   #10
Senior Member
 
Name: Bob Ruggles
Trailer: 2015 Escape
Michigan
Posts: 1,472
When in cruise my transmission automatically downshifts if my speed reaches 4-5 mph over the setting to hold the cruise setting. 2015 Ram 1500. My 2012 Chevy did the same thing.
rgrugg is offline   Reply With Quote
Old 05-27-2019, 10:03 AM   #11
Senior Member
 
Name: Bob
Trailer: Bigfoot 17G
Oregon
Posts: 105
Quote:
Originally Posted by thrifty bill View Post
I never use overdrive when towing, ever. My truck has a tow mode which automatically downshifts on down grades.

Read your owners manual and see what it says on using overdrive when towing.
That's what I've read and been told. In fact, the local RV mechanic has told me to NEVER use OD when towing. That said, it's very tempting since I am towing a 3000# trailer with a 2002 Chevy diesel pickup that seems to be loafing along even with the trailer behind it.

Any comments/thoughts about this will be appreciated. Thanks to all.
bobblangley is offline   Reply With Quote
Old 05-27-2019, 10:27 AM   #12
Junior Member
 
Name: Art
Trailer: Casita
Pennsylvania
Posts: 23
When towing I am more concerned about pulling with a loafing engine than one running at high RPMs. With my tear drop I rarely used the tow mode, but the Casita is heavy enough that I use it all the time. Does effect milage some but not as much as I thought it would. Id rather end my trip with a sound tranny and engine than trying to squeeze a few extra miles per gallon out of my rig.
ae6black is offline   Reply With Quote
Old 05-27-2019, 10:48 AM   #13
Member
 
Name: Deborah
Trailer: Currently shopping
CA
Posts: 71
So now I'm curious, since my vehicle doesn't have have a "tow driving" mode (does have a full tow package). What does tow mode do, exactly? Does it basically just automatically put the vehicle in a lower gear on downhill grades, or is there more to it?
DebiT is offline   Reply With Quote
Old 05-27-2019, 11:06 AM   #14
Senior Member
 
Name: Wayne & Barbara
Trailer: Parkliner
Iowa
Posts: 1,032
Downshifting

Most all tow vehicles can be downshifted. exception being a Highlnder Hybrid. but then it has dynamic braking, using the electric motor as a generator as it recharges the battery.
Rule of thumb is to use the same gear going down the hill as you need for going up.

If the grade is too long and/or steep. apply the brakes, but with intermittent harder braking, letting off so the drums or disks can cool. With hard braking they will not get hot as fast as with continuous light applications.
Wayne Collins is offline   Reply With Quote
Old 05-27-2019, 11:27 AM   #15
Senior Member
 
Jon in AZ's Avatar
 
Name: Jon
Trailer: 2008 Scamp 13 S1
Arizona
Posts: 8,494
Registry
Quote:
Originally Posted by bobblangley View Post
That's what I've read and been told. In fact, the local RV mechanic has told me to NEVER use OD when towing. That said, it's very tempting since I am towing a 3000# trailer with a 2002 Chevy diesel pickup that seems to be loafing along even with the trailer behind it.



Any comments/thoughts about this will be appreciated. Thanks to all.
How old is the mechanic?

For many years that was the recommendation from most manufacturers. It had more to do with how the overdrive gear was made than the actual ratio, which is, after all, just a number. Modern automatic transmissions have evolved, most have multiple overdrive ratios, and manufacturer recommendations have changed accordingly.

Youíd be better off reading the manual and perhaps talking (off the record) with a dealer transmission specialist.
Jon in AZ is offline   Reply With Quote
Old 05-27-2019, 11:52 AM   #16
Senior Member
 
M Scott's Avatar
 
Name: Marilyn
Trailer: 13 ft 2005 Scamp Deluxe; 2002 Subaru V6 Outback
Oregon
Posts: 257
Deborah, here's a neat trick I learned tp back up my trailer:
In your driver's side mirror, if you see the trailer moving to your left, turn your steering wheel left - slowly. You'll see the trailer straightening out. If in your right side mirror, the trailer is moving right, that's the direction to move your steering wheel. Wahlah...magic. The hardest part is not to oversteer.
As others have said, practice, practice...try church parking lots midweek...they're empty. Cones help.
M Scott is offline   Reply With Quote
Old 05-27-2019, 11:57 AM   #17
Senior Member
 
Dan Meyer's Avatar
 
Name: Dan
Trailer: Scamp
Minnesota
Posts: 622
Towing or not, the rules are as follows:

The engine is used to accelerate or maintain speed.

The brakes are used only to slow down; brakes are not to be used to maintain speed. If you are using your brakes to maintain speed you will be in trouble, and in very serious trouble quickly.

Use lower gears and your engine to control your speed going downhill.

--Dan Meyer
Dan Meyer is offline   Reply With Quote
Old 05-27-2019, 01:54 PM   #18
Senior Member
 
Name: Wayne & Barbara
Trailer: Parkliner
Iowa
Posts: 1,032
Backing a Trailer

another "trick" to learn is: Put your hand on the bottom of the steering wheel.
If you want the trailer to go left; move your hand to the left.
To go right, move the bottom of the wheel right.
As you slowly reverse, watch how the trailer moves, then bring the wheel back just enough to maintain the turn, or beyond to straighten out.
Wayne Collins is offline   Reply With Quote
Old 05-30-2019, 08:49 PM   #19
Senior Member
 
floyd's Avatar
 
Name: Floyd
Trailer: 2004 13 ft Scamp Custom Deluxe
IllAnnoy
Posts: 7,441
Registry
Quote:
Originally Posted by DebiT View Post
So now I'm curious, since my vehicle doesn't have have a "tow driving" mode (does have a full tow package). What does tow mode do, exactly? Does it basically just automatically put the vehicle in a lower gear on downhill grades, or is there more to it?
Tow Mode, much like Sport Mode, (on the modern 6-10spd automatics) generally reprograms the transmission shift strategy to hold gears a little longer on acceleration and also to provide engine braking when decelerating.
Read your manual. It could tell you a lot... do you know that most modern Automatics even have a manual shift mode.
floyd is offline   Reply With Quote
Old 05-31-2019, 07:33 AM   #20
Senior Member
 
Name: Justus
Trailer: Hymer Touring GT
Illinois
Posts: 226
Quote:
Originally Posted by floyd View Post
Tow Mode, much like Sport Mode, (on the modern 6-10spd automatics) generally reprograms the transmission shift strategy to hold gears a little longer on acceleration and also to provide engine braking when decelerating.
Read your manual. It could tell you a lot... do you know that most modern Automatics even have a manual shift mode.
My manual tells me "before descending a steep hill, slow down and downshift." It has some warnings to avoid sudden downshifts while already traveling downhill. It has a note that downshifting will cause an increase in engine speed. What it's missing is the optimal engine RPM I should aim for. The only guidance in this regard is to keep out of red on the engine tachometer. I guess this is something of trial and error/know your car issue.

I did find that the vehicle has a feature that will force the transmission into a higher shift range even while in manual mode if the computer detects that the engine speed is "too high" or transmission fluid temp is excessive. What is too high? What is excessive? Only Toyota knows. Although I recall reading that around 200F is the maximum sustained temp I want to see.

With the exception of engine braking, nowhere in the towing section does the manual mandate going into manual mode to tow.
__________________

Justus C 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
Why (let them go downhill)? nutter_scamp_owner Care and Feeding of Molded Fiberglass Trailers 22 03-17-2017 12:55 PM
driveway apron too steep? yyyyyguy Problem Solving | Owners Helping Owners 9 02-07-2012 01:35 PM
Dropped trailer on the freeway! CharleneM General Chat 16 06-01-2010 08:13 PM
RV rolls over steep cliff as RVer walks dog Ken C Jokes, Stories & Tall Tales 7 10-22-2009 06:00 PM
scamp on freeway Legacy Posts General Chat 1 08-08-2003 10:00 PM

» Upcoming Events
No events scheduled in
the next 465 days.
» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 01:18 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
×