Sway Bars vs Torsion Bars ???

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caper1973

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Still very much a newbie to the whole pop up trailering world ... learning as I go ...

recently sold our last unit and bought a 2006 Fleetwood Bayside.  Its a 12ft box, 2 ft. storage box, GVWR of 3500, UVW of 2630.  Towing with a 2007 Pontiac Montana SV6. 
I am wanting to add some extra safety to towing as I am noticing a slight bit of sway.  Is there a difference between Sway Bars and Torsion Bars ?  If so, what is the difference.  I did hear about such bars not only controlling the sway of the trailer, but also helping to 'lift' the rear of the tow vehicle .... Any direction / pointers would be useful ....

thx
 
As I read your post I have to think of what you mean by "Sway" and Torsion"

I have a Sway bar (or two) lying about there, this is a heavy duty bar with a friction brake, it is designed to prevent the trailer from changing angle (relative to the tow vehicle) and works quite well, I've used them on two trailers I've had with great success

The "Torsion"  bar, from what you say, is a Load Equalizing hitch,  It changes the weight distribution

The best way to tow is kind of like this --------------x------------  Where the first part is the tow vehicle and the 2nd is the trailer..Now it may be like this ___________-----------  That's ok too (or the other way around)

What you don't want is this \ /  or for that matter this __/ or --\  (Where the hitch is either the higest or lowest point on the trailer frame  You want both trailer and tow vehicle frame parallel to the ground

To get the tow vehicle level you use a load equalizing hitch, this transfers some of the weight so the tow ivehicle is level,  To get the trailer level you can use either a drop hitch or a riser hitch (Drop hitch upside down) if needed.  That way you end up with my 2nd line _____---- or --------_____ either one is ok

Torsion bars do this.. They also help with sway but I don't know how effective as I've not used 'em
 
The bars on a weight distributing (WD) hitch help balance the load by shifting some of the weight off the tow vehicle rear axle to the front axle. If your tow vehicle sags a bit in the rear when the trailer is hitched up, you need a WD hitch, which has torsion or "spring" bars.  Some of these hitches also do sway control via those bars, e.g. the Equalizer hitch or the Reese Dual Cam hitch.

There are also anti-sway bars that can be added to existing hitches. These are friction-type devices that simly dampen the side to side movement of the trailer. Not as effective as the systems built into the hotch, but they do help.

HOWEVER, if you feel trailer sway, odds are you simply do not have enough weight on the tongue of the trailer. You need 12-15% of the total trailer weight on the tongue or it will tend to sway at the slightest provocation. Rebalance the load to put more weight on the front and your problem should go away.
 
I have a high side trailer, Fleetwood Saratoga, and use both a sway bar and a weight distributing hitch.  Grateful for both of them.
The weight distributing hitch levels the car and trailer and keeps too much weight from the car's suspension system.
Have towed without the sway bar and had sway.  Not a lot, but enough to make me put the sway bar back on.  A 1000 lb weight distributing hitch cost $10 more than a 700 lb hitch and works better.

 
I have a friction sway bar on my hitch and it works well.  To reduce tongue weight, you might re-distribute your PUP contents to be closer or over the PUP axle, if you can't do the weight distribution hitch (can't remember requirements). 
 
I see a lot of scarry towing scenariors come rolling through the gates of the dealer ship i work at.
Gary has done an excellent job at explaining the differences.
I suggest an Equalizer hitch set up properly. As stated  earlier this type of hitch distributes the weight of the tow vehichle and the trailer evenly and if set up right the entire system willl be level.
Most of the scarry trailer set ups are do to lack of proper set up, and un even loads distributed throughout the trailer and the tow vehichle.
Haul with empty tanks when you can. keep the cargo over the axles. install your sway bars or torsion bars so they are parralell with the frame of the trailer. As stated earlier the tow vehicle and the trailer must ride level!! Some people slip in a receiver wtih just a 2/5/8ths ball  laod the crap out of the back of their pick up and put most of the cargo at the back end of their trailer. The water tank is full  and they are  travelling at speeds above 75 mph.  wondering why they are in the median laying on their sides with the tires spinning.
 
caper1973 said:
Still very much a newbie to the whole pop up trailering world ... learning as I go ...

recently sold our last unit and bought a 2006 Fleetwood Bayside.  Its a 12ft box, 2 ft. storage box, GVWR of 3500, UVW of 2630.  Towing with a 2007 Pontiac Montana SV6. 
I am wanting to add some extra safety to towing as I am noticing a slight bit of sway.  Is there a difference between Sway Bars and Torsion Bars ?  If so, what is the difference.  I did hear about such bars not only controlling the sway of the trailer, but also helping to 'lift' the rear of the tow vehicle .... Any direction / pointers would be useful ....

As others have said, you will need a weight distributing hitch system with two spring bars  -- what you call torsion bars.  The spring bars, properly adjusted, transfer trailer hitch weight to the front wheels of the tow vehicle, leveling the unit and reducing the tendency of a truck with excessive weight on the rear axle to over-steer.    In addition, a sway control is very desirable.  You have a light trailer so a friction bar sway control is probably adequate -- keep it adjusted per the mfr instructions.

A weight forward trailer is a stable trailer.  You should have 10% to 15% of the trailer's weight bearing on the hitch.  Therefore, you should load heavy stuff in the trailer ahead or over the axle(s), not behind them.    If your water tank is ahead of the axles, filling it can help stability.
 
Water in the tanks will increase weight but it wont make it stable.Water sloshing back and forth  creates a lot of movement.
 
If the water tank is full, it won't be "sloshing".
 
Do want you want ned and carl Its a bad idea to haul with loaded tanks. Also with the Equalizer brand hitch there is no need to add another sway control. Equalizer hitch is a 4 point sway controll and weight distribution hitch siystem its a great system.I dont work for Equalizer nor do i get sales commisions from them. I highly recommend this hitch when set up properly.www.equalizerhitch.com
 
Equalizer indeed has a good rep.  As does Reese Dual Cam and Hensley Arrow and I normally recommend them --  I like a system with inherent sway control.  However, for a trailer as light as 3500 lb GVWR  a friction rig would do.
 
thanks again guys.
I've now got a weight distributing hitch with the spring bars.  It's missing the bar, but I'll find one of those.  The camper comes out of storage tomorrow so I am looking forward to trying this new setup in a few days and expect to find a nice difference ...


 
certech said:
Do want you want ned and carl Its a bad idea to haul with loaded tanks.

I think I see where you are coming from Certech.  There is a thing called free surface effect or slosh.  (Yes for real - slosh.)  Tilting a tank partially full of fluid will cause the fluid to rush into the lower side of the tank causing the tank's center of gravity to suddenly and forcefully shift toward that side.  This shift can over balance the tank causing it to rotate over.  Most folks have experienced it when they tip over a half full water bucket.

It is quite dangerous in ships, aircraft and tanker trucks.  The hazard is reduced by baffling in the tank and placing the tank well below the center of rotation of the vehicle it is in.  It is eliminated by keeping the tank completely full, eliminating the free surface, or by emptying it.

The typical 40 gallon water tank on an RV carries around 40 gallons -- 320 lbs of water or 160 lbs half full.  The effect of a half full tank on a, say, 4000 lb trailer is damn near trivial -- especially since it is set very low in the trailer near or below the center of rotation.

In short a full RV water tank's only effect on stability will be to raise the hitch weight somewhat -- which is desirable
 
Whenever i do a trailer orientation with a customer i always warn against loading up your tanks with liquids and travelling for 2 reasons. I am convinced that the weigth in motion can cause the towed vehichle to pitch, and you wont be able to convince me otherwise. Like i said before,i see alot of scarry towing scenarios. Some folks come back from camping and their black and gray tanks are full their fresh is half full, they have 2- 30 pound propane tanks , to me that is a lot of unnecessary weight in motion. Liquid weight in motion is not stable.Get rid of all the unneccarry weight that you can .
The other reason i warn against driving with a loaded fresh tank is the possiblitly of the fill tube seperating from its connection points at the wall and at the tank .The tube is attached with hose calmps and hose clamps can and do losen up wether it be by the plastic being crushed or by the fittings werent tight in the first place.When clamps come loose so does the tubes emptying out all that water or some of that water. The owner may never even realize what has happened. When water moistens wood over a period of time... well im sure you know what happens. Yup, rot. Some tanks are mounted under neath the floor.inside the underbelly next to all that fiberglass insulation. Wet insulation is great for the wood above it. Others such as in a pop up they are mounted above the floor usualy under the booths.We technicians love to work on rotted floors it brings in a lot of income. ;D These two reasons is why i am convinced that driving with full tanks is a bad idea. :-*
 
Whenever i do a trailer orientation with a customer i always warn against loading up your tanks with liquids and travelling for 2 reasons. I am convinced that the weigth in motion can cause the towed vehichle to pitch, and you wont be able to convince me otherwise.

If that is the case, I won't try.  All I can say is the physics are pretty simple, and similar to the physics of boats which have been worked out for a lot of years.  A full tank set low in the vehicle has no more slosh effect than an empty tank, and any any effect on yaw would be offset by a position well forward which would move the trailer center of gravity closer to the hitch coupler, lessening the lever arm of the trailer over the tow vehicle.

On the other hand, if your black or gray tanks are aft of the axles, yes indeed a partially full or full tank has an adverse affect on yawing/sway.  Empty them out before traveling if you can at all.




 
Carl, I agree with you 100%. I fill my fresh water tank before leaving whenever I will be camping where there is no water hook up. I am within the 10-15% weight with or without the tank being full. If it is suggested to not fill the tank then what good is the tank. As far as sloshing older firetrucks had there tanks mounted (above the frames )with no baffles and were known for rollovers , now they are baffled. In my TT they tanks are in/below the frame which is a big difference.
 

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