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10-16-2016, 11:28 AM
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#1
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Rivet Master
2021 27' Globetrotter
Fort Lauderdale
, Florida
Join Date: Oct 2016
Posts: 606
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Downhill speed control
Hello, a search for 'braking' did not show any links, so if they are there and you know them, please let me know to avoid repeating info already available.
The use of down shifting to break with the engine works fine with the car/truck, my question is about the trailer: this way of controlling speed does not activate the brakes, so the electric braking system in the trailer will not actuate. Correct?
That being the case, the momentum (especially downhill) of the trailer will be slowed just by the ball in the TV (with the help of the swaying control bars?), which is probably not enough to avoid jackknifing.
To activate brakes on the RV we need to either manually depress the remote and/or put pressure on the TV brake pedal. Locking the RV's brakes if slippery may call for disaster, so I suspect there is a good way to handle the slowing down (even braking) in challenging road conditions. Anyone with actual experience on this, bad or good?
I guess deploying a parachute from the back of the AS is not an option (sailing, at least we have a parachute anchor to heave to)
Thank you
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10-16-2016, 01:19 PM
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#3
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Rivet Master
1988 25' Excella
1987 32' Excella
Knoxville
, Tennessee
Join Date: Oct 2010
Posts: 5,103
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I do not tow in "challenging" road conditions. On dry pavement or in rain on long descents I try to use as much engine and transmission braking as I can and use the brakes in pulses when needed. I try to apply the brakes before speed builds up. My two worries are catching the trailer brakes on fire from too much braking and breaking traction on the trailer wheels from too much braking.
On very slick descents I do not have a clue. I would try the same strategy as above at very low speeds and try to keep the trailer wheels rolling rather than locking and skidding. I would be traveling at speeds where sway is not a problem so would be happy to control the trailer speed with the hitch ball.
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10-16-2016, 03:03 PM
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#4
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Rivet Master
1991 34' Excella
Princeton
, New Jersey
Join Date: Aug 2003
Posts: 7,070
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If down shifting will not hold you back RIDE the brakes with light pressure. Stabbing them will generate more heat than lightly riding them and you will most likely lose your TV front brakes.
If light pressure will not hold you back reduce speed enough to shift down another gear.
You go down a hill in the same gear you went up it.
__________________
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles
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10-16-2016, 03:15 PM
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#5
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Rivet Master
1988 25' Excella
1987 32' Excella
Knoxville
, Tennessee
Join Date: Oct 2010
Posts: 5,103
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I agree with Howie that light riding of the brakes generates less heat. But I do not do it that way when towing. I can control how much pressure I am putting on the TV brakes but do not know exactly what the trailer brakes are actually doing. So I pump to control the amount of time the trailer brakes are on. Even though that way generates a bit more heat I think there is less of a chance of catching a axle on fire on a long downhill.
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10-16-2016, 03:24 PM
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#6
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Rivet Master
1991 34' Excella
Princeton
, New Jersey
Join Date: Aug 2003
Posts: 7,070
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Quote:
Originally Posted by Bill M.
I agree with Howie that light riding of the brakes generates less heat. But I do not do it that way when towing. I can control how much pressure I am putting on the TV brakes but do not know exactly what the trailer brakes are actually doing. So I pump to control the amount of time the trailer brakes are on. Even though that way generates a bit more heat I think there is less of a chance of catching a axle on fire on a long downhill.
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Don't sit for a CDL license with that approach you will fail.
__________________
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles
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10-16-2016, 04:05 PM
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#7
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Rivet Master
2021 27' Globetrotter
Fort Lauderdale
, Florida
Join Date: Oct 2016
Posts: 606
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Quote:
Originally Posted by Bill M.
I do not tow in "challenging" road conditions. On dry pavement or in rain on long descents I try to use as much engine and transmission braking as I can and use the brakes in pulses when needed. I try to apply the brakes before speed builds up. My two worries are catching the trailer brakes on fire from too much braking and breaking traction on the trailer wheels from too much braking.
On very slick descents I do not have a clue. I would try the same strategy as above at very low speeds and try to keep the trailer wheels rolling rather than locking and skidding. I would be traveling at speeds where sway is not a problem so would be happy to control the trailer speed with the hitch ball.
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I don't plan to drive under challenging conditions. Nevertheless, I prepare for them, as conditions change. If I can deal with them, it will make it for a safe trip.
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10-16-2016, 04:53 PM
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#8
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Rivet Master
2011 28' International
Chatham
, Ontario
Join Date: Dec 2010
Posts: 1,401
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For me with my relatively light tow vehicle, I select the gear and the speed I want to descend at BEFORE starting the descent. That can mean knocking your speed right off and upsetting other road users, but it's a whole lot easier starting a descent slowly than it is trying to slow down during the descent. I've used that technique when towing through the White Mountains in New Hampshire (and other places) and it's served me well so far.
Yes, the TV and trailer will pick up speed during the descent but, as others have said, light pressure on the brake pedal, when required, is generally enough to prevent you picking up too much speed and to stop the brakes overheating.
I learned the hard way, of course, when I first started towing. I needed to go down a short but steep hill, in the dark, and underestimated the severity of the grade. I was going too fast and needed to haul everything to a stop halfway down; I stopped OK but the big cloud of smoke and the smell of burning brake liners came past me as came to a halt. No damage done but it was certainly a driving lesson!
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10-16-2016, 06:31 PM
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#9
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Rivet Master
2013 31' Classic
billings
, Montana
Join Date: Feb 2010
Posts: 3,576
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Cummings with exhaust brake ,works like a charm, You are better to use steady pressure on your brake pedal than to pump them, down hill in same gear you went up.. That's trucking over Montana passes....
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10-16-2016, 06:52 PM
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#10
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Rivet Master
1986 34' Limited
1975 27' Overlander
1969 21' Globetrotter
Conifer
, Colorado
Join Date: Jun 2009
Posts: 8,291
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There is no doubt mountain descents are a challenge for the equipment and driver. The driver has full control, not the equipment. I'll take a chance and guarantee any long descent can be safely completed at 10 mph.
Overuse of the tow vehicle brakes or trailer brakes will overheat them, and they could "fade away" giving you much less braking ability. I saw a semi truck on Colorado I-70 shoulder last month with smoking hot brakes. Glad he got it stopped. Maybe his air brakes failed in some manner.
Disc brakes on the trailer significantly add to braking force available. Disc brakes tend not to fade as fast as drums. They are a good option on newer Airstreams.
I go down a long descent into Denver in the wife's vehicle in 3rd gear, 3000 rpm at 50 mph and hardly ever have to use the brakes.
I went down "Rabbit Ears" pass on CO 40 into Steamboat Springs with my diesel pick up and 8000 pound Airstream in 3nd gear at 3000 rpm at 45 mph and used the brakes very little. There are several curves on this descent. The diesel exhaust braking effect certainly helps. I did have quite a line of traffic behind me, and I pulled over when it was safe to do so. But I was in complete control all the way down.
If I'm lucky, I find a semi truck and follow him down the hill in the right lane. People in mountain states understand semi trucks need to go slow downhill for safety, and go slow uphill due to power limitations.
David
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10-18-2016, 09:28 AM
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#11
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4 Rivet Member
Vintage Kin Owner
St. Louis
, Missouri
Join Date: Jul 2016
Posts: 415
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Got my first taste of steep descent with a trailer two weeks ago on a drive to the west coast followed by a tour around Yellowstone. We crossed the Continental Divide several times in a matter of days. Dunraven Pass was our highest elevation at 8,859 ft. But the longest steepest descents were on the interstate. One hill in Montana had a 25 mph speed limit for trucks over 12,000 lbs. (I’m nearly 16,000 lbs.)
MrUKToad is correct. Select your speed BEFORE you begin the descent. What other drivers think of your speed is none of your business. Would you rather have them angry for getting stuck behind you, or think you are a fool for flying downhill too fast? If you’re going too fast, those who think you are a fool are correct.
I have a CDL with passenger endorsement, but was unable to be tested on steep hills since there are none in my area. Our recent trip put that technical knowledge to good use. The CORRECT way to descend is brake BEFORE the hill. Most major roadways will have a sign telling you 5, 6, or 7%. This will tell you what gear you need, and how much braking you will do. I learned that with my setup, 5% feels good at 50-60 mph, 6% 35-45 mph, and 7% 25-35 mph. At 6%, I brake to 35 before the hill, and put my 6 speed tranny in 3rd. DONT TOUCH THE BRAKE until the truck reaches 45. Then press the brake firmly (no jabbing) to slow the truck from 45 back to 35. Then take your foot OFF the brake while it slowly climbs back to 45.
If the truck races back to your top speed, you are in the wrong gear. Brake to the right speed, and downshift further. As long as you are not violating your redline, the scream of your racing engine is perfectly harmless, and using no more gas than you do at idle. (I had to reassure my alarmed wife repeatedly.)
Riding your brake lightly produces enormous heat with nearly zero benefit. The heat will cause brake failure without causing a fire. You won’t know you’ve lost your brakes until you really need them. Jabbing the brakes could jackknife your trailer.
When descending at reasonable speed, the load PUSHING on your trailer hitch is the same as the load PULLING on your hitch when you are accelerating normally. When braking normally on a steep hill (ex. from 45 down to 35) your trailer brakes are engaged normally, and your load will remain straight.
__________________
The Morgans
1989 Avion 34VB
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10-18-2016, 09:53 AM
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#12
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Rivet Master
1962 28' Ambassador
1961 19' Globetrotter
1962 26' Overlander
Mesa
, Arizona
Join Date: Jun 2013
Posts: 5,996
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Am following this and previous threads about proper downhill descent methods.
In our Chevy pickup we have PRND321 and a Tow Haul button.
Don't understand this comment and have seen it previously: you go down the same gear you go up. Well I went up the hill in D/Drive....?
__________________
Hittenstiehl
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10-18-2016, 10:18 AM
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#13
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Rivet Master
2021 27' Globetrotter
Fort Lauderdale
, Florida
Join Date: Oct 2016
Posts: 606
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Thank you, very good info. Two questions (for whomever can/wish to answer):
1. I have to bacK up my trailer, up my 100 yards driveway, which is one lane wide, curves up the hill to my garage. I was able to do this with my LR4 pushing up my FC27. I need a bigger truck and will go all the way to F350 to avoid regrets (dam, I wanted a larger one!) down the road. Question is about maneuvering the trailer up the driveway. A longer wheel base will make that maneuvering too difficult/impossible? I guess the longer, the larger the turning radius and considering the driveway is narrow (maybe 150% of the with of a car), what I did with the short LR4, is repeatable with a F350?
Thanks.
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10-18-2016, 10:49 AM
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#14
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Rivet Master
Currently Looking...
Mantua
, Ohio
Join Date: Jul 2005
Posts: 7,062
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Front hitch on truck, go forward up the driveway.
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10-18-2016, 10:54 AM
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#15
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Rivet Master
Vintage Kin Owner
N/A
, N/A
Join Date: Sep 2012
Posts: 989
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Quote:
Originally Posted by Hittenstiehl
Am following this and previous threads about proper downhill descent methods.
In our Chevy pickup we have PRND321 and a Tow Haul button.
Don't understand this comment and have seen it previously: you go down the same gear you go up. Well I went up the hill in D/Drive....?
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I think it means, for example, if your TV drops to 2nd gear to go up a grade, you should also go down the grade in 2nd gear (not 3rd or higher), by manually shifting to 2nd gear. This is to take advantage of engine braking.
As for downhill speed control best practices, I use Mountain Directory app ( http://www.mountaindirectory.com/) and identify steep inclines/declines before hand. They have separate apps for East/West coast.
Going up is usually much easier (I use cruise control, and lower the speed depending on the grade). Going down, I reduce my speed to the suggested truck speed limit, manually down shift the transmission, and start the descent (I do not use cruise control). I have not been to the west coast, but we seem to have some challenging hills in the Appalachians. Going down a 2 mile 10% grade, I downshift to 2nd gear, reduce my speed to 30 MPH, and let the RPMs climb up. Right at the point where the transmission is about to up shift to 3rd gear, I apply the brakes to reduce the speed. I repeat these steps. Going down a 2 mile long 10% grade, I had to apply the brakes around 5 times. I prefer to follow a semi in the right most lane.
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10-18-2016, 11:00 AM
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#16
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Rivet Master
1962 28' Ambassador
1961 19' Globetrotter
1962 26' Overlander
Mesa
, Arizona
Join Date: Jun 2013
Posts: 5,996
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Thx Rostam that's a bit clearer.
__________________
Hittenstiehl
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10-18-2016, 11:14 AM
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#17
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Rivet Master
2021 27' Globetrotter
Fort Lauderdale
, Florida
Join Date: Oct 2016
Posts: 606
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Quote:
Originally Posted by avionstream
Front hitch on truck, go forward up the driveway.
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Yes, i guess i forgot to mention that once up the driveway, the width of the pavement in front of garage is not large enough to allow me to go up TV first, position the RV on the good spot, unhitch and drive the TV around and away back to the road. I need to go up AS first, backing up.
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10-18-2016, 12:55 PM
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#18
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Rivet Master
1962 28' Ambassador
1961 19' Globetrotter
1962 26' Overlander
Mesa
, Arizona
Join Date: Jun 2013
Posts: 5,996
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I think that's what he is saying. You would go Airstream first, back/butt end up first. Then unhitch and back your tow vehicle back down the driveway.
So you are mounting a tow hitch on the front of your tow vehicle and pushing your baby up instead of pulling but still going the same direction.
__________________
Hittenstiehl
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10-18-2016, 01:04 PM
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#19
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Rivet Master
Currently Looking...
Mantua
, Ohio
Join Date: Jul 2005
Posts: 7,062
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That's it. Hook thr trailer to the front hitch and drive forward pushing the trailer.
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10-18-2016, 01:42 PM
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#20
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Vintage Kin
Fort Worth
, Texas
Join Date: Nov 2006
Posts: 8,014
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Most if not all front receivers are not capable of the TW of one of these trailers.
1990 35' Silver Streak
2004 555 Cummins
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