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Old 05-03-2012, 07:33 PM   #113
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Name: Norm and Ginny
Trailer: Scamp 16
Florida
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Carol,

Sway is an interesting problem. I'm not sure having a heavy tow vehicle or a tow vehicle with an appropriate manufacturer's rating makes a real difference in a swaying adventure. As I mentioned I've seen people with sway who had heavy tongue weights and big tow vehicles.

The appropriate thing is to watch for low level swaying and do something about it before it becomes the dangerous variety occurs. If one sees a little sway stop the vehicle and address the loading issues. (I suspect that big sways are more often associated with high speeds.)

I agree with using the brake controller to stop sway.

On this forum and others I have sought people who've had a swaying accident. I have yet to find a single person. I have met two large trailer owners with appropriate tow vehicles who have totaled their trailers in swaying events. Neither person understood how it happened.


As to wheelbase, certainly longer is better but what is equally important is the distance from the ball to the center of the rear axle. It is the ratio of the distance from ball to rear axle to the length of the wheel base that is important.

As to using the trailer's brake controller to kill sway, every day that we hook up and start out I reach over and activate the brake controller to check the trailer brakes and to insure that I can reach that lever without looking.

As well another factor is the stiffness of the tires.

I will say that I get a number of PMs about our tow configuration. I never say simply "go for it" or the like. I always mention our total setup, including tire pressures, tongue weights and our approach to driving. I suggest for everyone trailer brakes no matter the trailer size.

The magic of the information age, the Internet and this forum is the ability to share information, both fact and opinion. To not share my experience would be wrong.

As to carbon footprint, it never concerns me except for the cost of fuel and the effect of rising costs on the economy.

Safe travels, Carol, you seem like a very calm, Canadian person...
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Old 05-03-2012, 07:54 PM   #114
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Name: Logan
Trailer: 1976 Scamp 13'
Wisconsin
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Originally Posted by ruscal View Post
On long downgrades without the trailer brakes ability to help the truck he would be grossly overpowering his TVís brakes requiring maximum engine braking being only applied to the drive axles. They probably have safety features built into the braking systems which increase reliability or include redundant features to take over if one device fails.
Russ
The compression brake (aka "Jake" or "Engine") is much more powerful than the truck's air brake system. A long grade will overheat the shoes and drums causing the truck to lose much of its braking ability. Good drivers do not use their base (air) brakes on a grade. They should downshift and use the compression instead. If the trailer starts acting up, careful application of the trailer brakes (via the Johnny bar)can get it back in line.
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Old 05-03-2012, 08:07 PM   #115
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Trailer: 1976 Scamp 13'
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Big rigs use air brakes on the trailer, the brakes are spring loaded to be engaged and only air pressure from the TV supplied by the hoses you see in the back middle of a rig keep the brakes disengaged. Brake pedal bleeds off air pressure. Brake line fails brakes will engage. Brake canisters at the wheel fail brakes will engage. There is more than one control to bleed off air pressure. Parking and foot brake at the least.

The spring brakes are used only for parking and as a safety backup. Air pressure is what applies all of the truck/trailer brakes under normal operating conditions. Air pressure is used to keep the springs disengaged while the truck is underway. Should a major air malfunction occur (First, the air gauge drops and a buzzer sounds), the reserve air holding the spring back can be released in a controlled manner to bring the truck to a stop. The backup valving is located in the brake pedal and automatically engages. Once this air reserve is depleted, the truck isn't going anywhere until the system is repaired.

Oh, and never, ever open the spring brake chamber. The spring is under extreme pressure and can easily kill anyone in its path.
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Old 05-03-2012, 08:50 PM   #116
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Name: Russ
Trailer: Scamp 16' side dinette, Airstream Safari 19'
California
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Originally Posted by 841K9 View Post
The compression brake (aka "Jake" or "Engine") is much more powerful than the truck's air brake system. A long grade will overheat the shoes and drums causing the truck to lose much of its braking ability. Good drivers do not use their base (air) brakes on a grade. They should downshift and use the compression instead. If the trailer starts acting up, careful application of the trailer brakes (via the Johnny bar)can get it back in line.
Logan,
That makes sense. The brakes would heat up after continued usage. Compression braking should do the lion's share of the work. If the truck were to lose a driveshaft it could then test the brakes staying power!
Russ
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Old 05-03-2012, 09:03 PM   #117
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Logan,
That makes sense. The brakes would heat up after continued usage. Compression braking should do the lion's share of the work. If the truck were to lose a driveshaft it could then test the brakes staying power!
Russ
An old 'Pete 379 was brought into our shop missing just that- The whole front driveshaft.

The driver claimed that he didn't feel a thing.
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Old 05-03-2012, 09:18 PM   #118
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Name: Russ
Trailer: Scamp 16' side dinette, Airstream Safari 19'
California
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Sway check

I have not checked my tongue weight yet, so have been just going by feel so far. When I bought the trailer I towed it home with my Jeep. The trailer was empty. It towed beautifully, with great tracking feel and no sway. I wouldn't have known it was there except for slower acceleration, and a clunk clunk of the receiver rattling.
The next trip I had the rig loaded for a weekend trip with all gear, food and water. After taking off I noticed right away a light vague steering feel and thought "this ain't right". I started on a gentle downhill run and got up to about 40mph, decelerated and the trailer went into the death dance. It wasn't subtle. I used the manual trailer brake lever to calm the oscillation and pulled over to the side to shift some weight around. I had put too much stuff on the trailer floor aft of the axle. I moved a few things forward as far as they would go and took off for another test run. The difference was amazing. No light steering or sway. I descended another hill and did some slalom turns while holding light tow vehicle braking with no effect. I gained enough loading experience to know what I can expect by doing what. A more scientific method would be to weigh the tongue each time the trailer would be used, and stay around 12%. I would need a convenient scale set up to do it through. I now just use the slalom test each time I load up.
Russ
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Old 05-03-2012, 10:17 PM   #119
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Trailer: 2004 13 ft Scamp Custom Deluxe
IllAnnoy
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Originally Posted by 841K9 View Post
The compression brake (aka "Jake" or "Engine") is much more powerful than the truck's air brake system. A long grade will overheat the shoes and drums causing the truck to lose much of its braking ability. Good drivers do not use their base (air) brakes on a grade. They should downshift and use the compression instead. If the trailer starts acting up, careful application of the trailer brakes (via the Johnny bar)can get it back in line.
That's oranges fer sher, but it sorta makes a good point.
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Old 05-03-2012, 10:31 PM   #120
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That's oranges fer sher, but it sorta makes a good point.
Kind of, but it is sill applicable to our rigs.

It is very easy to overheat most factory auto and light truck brakes. Downshift if a standard transmission or use the tow/haul/overdrive cancel mode on a slushbox (automatic) to control speed on a long grade.

I have a Pacbrake on both of my diesel tow vehicles and absolutely love it. If you have a diesel- get one. You won't be disappointed.
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Old 05-04-2012, 01:42 PM   #121
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Name: Norm and Ginny
Trailer: Scamp 16
Florida
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Russ,

It's very easy to weigh your tongue with a standard bathroom scales. I do it every few months as we travel. it doesn't seem to vary by more than +/- 10 pounds. The difference seems to be the state of our propane tank. Ours is basically 200 pounds +/- 10 pounds on a 2400 pound trailer.
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Old 05-04-2012, 02:59 PM   #122
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Name: Russ
Trailer: Scamp 16' side dinette, Airstream Safari 19'
California
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Russ,

It's very easy to weigh your tongue with a standard bathroom scales. I do it every few months as we travel. it doesn't seem to vary by more than +/- 10 pounds. The difference seems to be the state of our propane tank. Ours is basically 200 pounds +/- 10 pounds on a 2400 pound trailer.
Norm and Ginny,
Mine is probably too heavy to use a bathroom scale without using an uneven fulcrum to derate the scale. Mine should tow well at 300lbs. since it is around 2800 loaded.
I was thinking about fabbing up a simple teetertotter gizmo that would enter the bottom of the coupler and could be simply pivoted into position.
The fulcrum could be a jackstand like dealy. The lever could be unequal so I could push down on it to lift the trailer to a level attitude. I could use a bathroom scale attached to the lever and directly read the scale while pushing down. Pretty MacGyver, but could work. Just use a factor to get the real wieght.
It could be much simpler with a proper scale though! I would need a 350 lb bathroom scale.
Russ
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Old 05-04-2012, 05:09 PM   #123
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Name: RogerDat
Trailer: 77 Scamp 13
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Once this air reserve is depleted, the truck isn't going anywhere until the system is repaired.

Oh, and never, ever open the spring brake chamber. The spring is under extreme pressure and can easily kill anyone in its path.
Your description of brake system was more accurate than mine. And more modern. The only air brakes I ever worked on personally are the ones on my 1975 IH school bus camper conversion. On reflection it was as you say air actuated. What I drove for a living was always fleet maint.

Had a leaking diaphram in Colo. just the other side of all places Pegosa Springs after going over wolf creek pass of C.W. McCall fame. Had to stop to build up air pressure three or four times to release brakes and limp two blocks to a repair facility. As we both stated no air = no go.

They only sold rebuilt or new chambers, mechanic showed me the hole busted through the side of the metal pole barn where a spring had busted loose when someone was doing an onsite rebuild of the brake chamber. They stopped doing them after that.
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Old 05-04-2012, 05:25 PM   #124
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Name: Michael
Trailer: Li'l Hauley
Oklahoma
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Thanks for the reply, Carol. What do folks do who dont have trailer brakes at all or like in my case I have surge brakes which only apply when the tow vehicle decelerates. Thankfully I've never experienced sway with either of my 2 popups or my T@b but would like to know my options if it ever occured. What about just letting off the gas of the tow in order to hopefully slow down hard enough that the trailer brakes on my T@b will engage? I doubt speed will ever be a factor as I tow between 55 and 60 mph so not sure if slowing up would help or if in that case I should actually speed up a bit to pull the trailer back into line if I cant get the brakes to engage by slowing down without actually hitting my tow brakes? What about folks who have no kind of trailer brakes. What are their options?

Thanks again!

Melissa
Option 1: prayer, and a bit of acceleration
Option 2: fervent prayer

As you can see, I am not a fan of surge brakes.

However, if you want to be cautious, you can weigh the tongue after loading and before pulling out for vacation. For your T@B a tongue weight of at least 150 lbs should keep you from ever having oscillation-sway.
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Old 05-04-2012, 06:18 PM   #125
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Name: Dave
Trailer: Bigfoot 25 RB and Bigfoot 21RB
British Columbia
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One of the many reasons that I hate despise and loathe (as much as not much caring for) surge brakes is that - when you get into a really bad sway situation, when you hit your car/truck brakes, there is a VERY good chance that you can make things a LOT worse in a real hurry. Unless you manage to hit the brakes when the trailer is (more or less) right behind you (and therefore sorta straight - in mid wag) your life can get very "interesting".

Assume the worst case - your trailer is way out to one side or the other when you abruptly slow the tug - the trailer may not press 'forward" on the brake activator, but instead may keep going and attempt to pass you. THAT is when you gotta get back on the throttle, fast, to get back ahead of it so you can then apply brakes with it behind you again and bring the entire rig to a stop, preparatory to changing pants and arranging to get the car seat cleaned.

(Even adamant non-smokers need a cigarette about then and even non-drinkers need a good stiff shot). Don't worry - you'll stop shaking in a while and you'll now be a MUCH better driver as well.

Don't load tail-heavy
Do keep 10% or so of trailer weight on the hitch
If need be, get a lighter trailer or a heavier tug (or both)
Be prepared to drive slower

(Did I mention I dislike surge brakes?)

Speed and trailer weight are major contributing factors, but there are others as well. Go out to your driveway. Push on one side of your tug, near the rear wheels. Did the car move sideways a bit over the wheels? Of course it did. That's the tire sidewalls flexing. Now do the same with your trailer. Yup.

That little bit of sideways movement will set up a bit of sway and when the car zigs at the same time the trailer zags, the relative sway is enhanced. Still not much - not enough to be really noticeable, but that is where things can start. If you can minimize this sidewall flex, (by carrying the highest tire inflation stated on the sidewall) you can reduce your chances of things getting out of hand.

(And, in case I forgot to say it, I favor the use of electric brakes over surge.)
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Old 05-04-2012, 06:18 PM   #126
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Name: Logan
Trailer: 1976 Scamp 13'
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Your description of brake system was more accurate than mine. And more modern.
I sure hope it was accurate.

I work on medium and heavy duty trucks for a living.
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