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Author Topic: Do I need sway bars?  (Read 11117 times)

battaglia

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Do I need sway bars?
« on: July 28, 2012, 06:36:17 PM »
Hello,

I am completely new to all of this, so please forgive any errors and my complete ignorance on the subject. I have a 2007 Jeep Commander 4.7L/V8. I am looking to purchase a 2006 Gulf Stream Amerilite. It is 21 feet with a dry weight of 3294lbs. The tongue weight is @350lbs. My vehicle is not currently tow equipped. I am taking it in to have everything installed. My question is.... Am I okay with a weight distribution hitch or do I need the weight distribution/sway bar hitch that the installer is recommending? I spoke with the gentleman I am puchasing the used travel trailer from and he says the trailer comes equipped with sway bars. Is this possible? I'd really appreciate any help.

Thank you!

Frizlefrak

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Re: Do I need sway bars?
« Reply #1 on: July 28, 2012, 09:46:07 PM »
The short answer is yes.  The first time you tow it in a crosswind or when a semi or bus passes you, you'll understand why.  If the seller is throwing it in, definitely use it.
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garyb1st

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Re: Do I need sway bars?
« Reply #2 on: July 28, 2012, 10:52:46 PM »
The trailer will likely weight more than 4,000 lbs when loaded.  Make sure your Commander is able to pull it safely.  The weight distributing and anti-sway bars are usually purchased separately, so if they're included in the deal you're saving a few bucks. 
Gary Brucker
1999 Rexhall Aerbus 32' Ford chassis. 
2008 HHR

Frizlefrak

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Re: Do I need sway bars?
« Reply #3 on: July 28, 2012, 11:03:12 PM »
I'm with Gary.  You may be pushing the limits on the Commander.  Would be worth looking into what the tow rating is.  Find your Gross Combined Weight Rating on the Commander, and subtract out the weight of the vehicle, passengers, fuel, and luggage, and what's left is what you can safely tow. 
2014 Ram 2500 Cummins
2012 Palomino 30' TT

Gary RV Roamer

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Re: Do I need sway bars?
« Reply #4 on: July 29, 2012, 10:17:06 AM »
Trailers don't come with anti-sway bars or devices - the previous owner must have been thinking of something else.

A WD hitch with anti-sway control built in (integrated) is highly recommended, for both safety and convenience. I like the Equal-i-zer, Reese Dual Cam, Hensley Arrow or Pro-pride brands. The last two are ultra-expensive but set the gold standard for hitches. The first do do a fine job, though, and should be plenty adequate for your trailer.

BTW, those bars on the hitch are not "sway bars" - they are the weight equalizing mechanism. The anti-sway function is either intergrated in the hitch head or accomplished with an add-on friction pad device that you manually adjust.
« Last Edit: July 29, 2012, 10:19:39 AM by Gary RV Roamer »
Gary
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BigDfromTN

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Re: Do I need sway bars?
« Reply #5 on: July 29, 2012, 07:18:04 PM »
As Gary touched on.  Many people thing those "bars" are sway control.   They are not.

Get the Sway control of some sort.  You may never know how glad you are you did!!

Gizmo

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Re: Do I need sway bars?
« Reply #6 on: July 29, 2012, 09:41:53 PM »
Yes you will avoid a white knuckle freak show and enjoy your towing experience more and with added safety.  I cannot say enough about the Hensley anti sway/weight distribution hitch.  I have the Cub (for trailers under 6K lbs.) and it has performed flawlessly. For over 6K lbs, the Hensley Arrow is the appropriate choice.  Having said that, I have to agree with the others on the towing specs of your vehicle for the trailer you are considering. 
Regards, Bruce, Lin An & Kenji
2014 Northwoods Snow River 246RKS
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2012 Ram 1500 Hemi Sport Red (Clifford)
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Frizlefrak

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Re: Do I need sway bars?
« Reply #7 on: July 29, 2012, 10:20:59 PM »
Yes you will avoid a white knuckle freak show   

ROFL....that describes it perfectly.  Only had it happen once when I was young and didn't know any better.  Nothing gets your attention like a swaying trailer. 
2014 Ram 2500 Cummins
2012 Palomino 30' TT

Jim Godward

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Re: Do I need sway bars?
« Reply #8 on: July 29, 2012, 10:28:36 PM »
Last time I went to Livingston on the way back we almost got hit while passing a trailer that started swaying just as we got along side.  I noticed it and hit the gas andwas just ahead of the trailer as it got crossways in my lane and the car was still almost straight ahead in the no 2 lane.  I'm sure they were scared, I was.
Jim
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Frizlefrak

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Re: Do I need sway bars?
« Reply #9 on: July 29, 2012, 10:31:27 PM »
Last time I went to Livingston on the way back we almost got hit while passing a trailer that started swaying just as we got along side.  I noticed it and hit the gas andwas just ahead of the trailer as it got crossways in my lane and the car was still almost straight ahead in the no 2 lane.  I'm sure they were scared, I was.

Yikes....how fast were they going?
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Mopar1973Man

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Re: Do I need sway bars?
« Reply #10 on: July 30, 2012, 05:51:54 PM »
Lot of swaying can be reduced by just slowing down too... Like I've got a 3/4 ton Dodge Ram and 30 Foot Jayco and found that keeping speeds down helps a bunch. Oh Yeah... No sway control on my trailer but I do have weight distribution bars...  8)
Mopar1973Man (AKA: Michael Nelson) located out in the state of Idaho with...
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Lowell

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Re: Do I need sway bars?
« Reply #11 on: July 30, 2012, 06:05:33 PM »
No sway control on my trailer but I do have weight distribution bars...  )

Same for me.  When I got my TT, I had a sway control left over from a previous trailer, but never found a need to have them installed.  On the other hand, nothing wrong with installing a sway control device.
Lowell

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pulled by 2009 Dodge 1500 Crew Cab 4X4
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Gary RV Roamer

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Re: Do I need sway bars?
« Reply #12 on: July 31, 2012, 10:28:23 AM »
Sway is also affected by trailer balance. The MORE weight there is on the tongue, the LESS sway. A tongue weight under 10% will start swaying at the slightest provocation, whereas 12%-15% probably won't sway except in extreme conditions.
Gary
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Mopar1973Man

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Re: Do I need sway bars?
« Reply #13 on: July 31, 2012, 06:55:43 PM »
(Not to hijack)

Gary... But will too much tension on the WD bars do the same too? Curious???
Mopar1973Man (AKA: Michael Nelson) located out in the state of Idaho with...
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2013 BigTex 70TV Utility Trailer

Frizlefrak

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Re: Do I need sway bars?
« Reply #14 on: July 31, 2012, 07:31:50 PM »
(Not to hijack)

Gary... But will too much tension on the WD bars do the same too? Curious???

Good question.  Seems like that would artifically load the front of the truck.

And I'm with Mopar Man.  55 MPH, zero sway with a 30' trailer.  Very tiny suck and push with semis at that speed too.  I've learned to compensate for it before it happens.
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BigDfromTN

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Re: Do I need sway bars?
« Reply #15 on: July 31, 2012, 10:25:24 PM »
(Not to hijack)

Gary... But will too much tension on the WD bars do the same too? Curious???

Not sure about too much tension but suspect drivability will suffer in some way.

I towed my trailer a short distance. On that trip I dropped one to few links and the trailer was much more "Herky Jerky" than normal. 

The time spent setting up a hitch properly is a good investment!!!

egwilly

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Re: Do I need sway bars?
« Reply #16 on: July 31, 2012, 10:34:37 PM »
Just my opinion....get and use a WD hitch and sway control. You won't regret it!  If you don't, someday you may.  :-\

Mopar1973Man

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Re: Do I need sway bars?
« Reply #17 on: August 01, 2012, 09:24:50 AM »
Just my opinion....get and use a WD hitch and sway control. You won't regret it!  If you don't, someday you may.  :-\

Reason why I asked because 99% I'm dry camping with my RV. Now I know my water tank is 50 gallons and located back by the rear bumper of the trailer. So when I left the house it was a bit squirrelly at times. Then one trip I let the bar down to the last chain link and WOW! Huge difference it drove very controlled and very solid. My Truck is already got the Camper Special suspension on it. So even without my WD bars it sits nearly level.
Mopar1973Man (AKA: Michael Nelson) located out in the state of Idaho with...
2002 Dodge Ram 2500 5.9L Cummins Turbo Diesel
2000 Jayco Eagle FBS 296
http://articles.mopar1973man.com/members-rides/17-mopar1973man/27-2000-jayco-eagle-296-fbs
2013 BigTex 70TV Utility Trailer

Carl L

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Re: Do I need sway bars?
« Reply #18 on: August 01, 2012, 01:06:11 PM »
(Not to hijack)

Gary... But will too much tension on the WD bars do the same too? Curious???

Trucks, and most cars, are normally are set up with an nose-heavy understeer configuration.   In  understeer, the vehicle will tend to resist a turn and try to maintain or resume a straight line course.   The vehicle is said to "plow" a turn.   This is the most controllable/stable steering configuration.
 
Oversteer, on the other hand, is the condition in which the vehicle tends to move easily and quickly into a turn, tending to turn tighter as it continues in the turn.  The vehicle will "dive" into a turn and evince a tendency to get "sideways" in turning.   Steering with be nervous and unstable require constant correction with the steering wheel.
 
Wikipedia's article on the subject:
 
When an understeer vehicle is taken to frictional limits where it is no longer possible to increase lateral acceleration, the vehicle will follow a path with a radius larger than intended. Although the vehicle cannot increase lateral acceleration, it is dynamically stable.
 
When an oversteer vehicle is taken to frictional limits, it becomes dynamically unstable with a tendency to spin out. Although the vehicle is unstable in open-loop control, a skilled driver can maintain control a little past the point of instability with counter-steering. However, at some limit in lateral acceleration, it is not physically possible for even the most skilled driver to maintain a steady state and spinout will occur.  [ http://en.wikipedia.org/wiki/Oversteer ]
 
Over-tightening WD spring bars will transfer an excess of trailer tongue weight forward onto the truck's front axle.  It will act to slightly stiffen the trucks steering and increase the understeer condition.  It will increase the resistance to turning.   Not all that great, but not a major concern.   
 
The opposite, under-tightening the bars, will shift the tongue weight back onto the rear axle and increase the oversteer tendency.  This will significantly increase the instability of the tow.   That is a really major concern.   In towing a trailer, oversteer is not our friend.   8)
Carl L/LA   [Forum Staff]  KI6SEZ

Prowler 23LV TT pulled by a '95 Ford Bronco

BigDfromTN

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Re: Do I need sway bars?
« Reply #19 on: August 01, 2012, 04:34:18 PM »
Trucks, and most cars, are normally are set up with an nose-heavy understeer configuration.   In  understeer, the vehicle will tend to resist a turn and try to maintain or resume a straight line course.   The vehicle is said to "plow" a turn.   This is the most controllable/stable steering configuration.
 
Oversteer, on the other hand, is the condition in which the vehicle tends to move easily and quickly into a turn, tending to turn tighter as it continues in the turn.  The vehicle will "dive" into a turn and evince a tendency to get "sideways" in turning.   Steering with be nervous and unstable require constant correction with the steering wheel.
 
Wikipedia's article on the subject:


 
When an understeer vehicle is taken to frictional limits where it is no longer possible to increase lateral acceleration, the vehicle will follow a path with a radius larger than intended. Although the vehicle cannot increase lateral acceleration, it is dynamically stable.
 
When an oversteer vehicle is taken to frictional limits, it becomes dynamically unstable with a tendency to spin out. Although the vehicle is unstable in open-loop control, a skilled driver can maintain control a little past the point of instability with counter-steering. However, at some limit in lateral acceleration, it is not physically possible for even the most skilled driver to maintain a steady state and spinout will occur.  [ http://en.wikipedia.org/wiki/Oversteer ]
 
Over-tightening WD spring bars will transfer an excess of trailer tongue weight forward onto the truck's front axle.  It will act to slightly stiffen the trucks steering and increase the understeer condition.  It will increase the resistance to turning.   Not all that great, but not a major concern.   
 
The opposite, under-tightening the bars, will shift the tongue weight back onto the rear axle and increase the oversteer tendency.  This will significantly increase the instability of the tow.   That is a really major concern.   In towing a trailer, oversteer is not our friend.   8)

Not disputing anything you say here!!!

BUT I do know that a trailer with too little tongue weight is VERY unstable as well.   What I am unsure about is can you "Take Away" enough tongue weight with a WD hitch to cause this unstable condition????

Carl L

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Re: Do I need sway bars?
« Reply #20 on: August 01, 2012, 07:12:29 PM »
Not disputing anything you say here!!!

BUT I do know that a trailer with too little tongue weight is VERY unstable as well.   What I am unsure about is can you "Take Away" enough tongue weight with a WD hitch to cause this unstable condition? ???

And indeed it would be unstable.   A WD hitch does not take any weight away.  It is all still there.   Some of it is merely transferred to the front axle from the rear axle of the tow vehicle.  The object is to restore the proportion of weight distribution normal for the unladen vehicle.   That is why you adjust a WD hitch by restoring the attitude of the truck to its unladen proportions. See our Library for the procedure.
 
Imagine the coupler ball as attached to the truck frame by a solid bar.   That bar and the frame ahead of the bar constitute a level with its fulcrum (pivot) at the rear axle.   Load tongue weight on the coupler ball and the lever pivots the front of the frame up taking load off the front axle.  A WD hitch acts on frame twisting the receiver which is welded/bolted to the frame up forcing the front down thereby restoring the proportions of weight.
 
Gottit?  No?  Go out to a park and tinker with the teeter-totters and you should catch on to the idea.  The board can be moved back an forth on the pivot a bit so a skinny kid can balance a big one.  Even so, the balance may not be exact so the big kid has to push up a bit to allow the little one to get back down.  That push is what the spring bars of the WD hitch provide -- more or less.
 
Time for a drink?  ???
Carl L/LA   [Forum Staff]  KI6SEZ

Prowler 23LV TT pulled by a '95 Ford Bronco

Gizmo

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Re: Do I need sway bars?
« Reply #21 on: August 01, 2012, 08:31:06 PM »
Trucks, and most cars, are normally are set up with an nose-heavy understeer configuration.   In  understeer, the vehicle will tend to resist a turn and try to maintain or resume a straight line course.   The vehicle is said to "plow" a turn.   This is the most controllable/stable steering configuration.
 
Oversteer, on the other hand, is the condition in which the vehicle tends to move easily and quickly into a turn, tending to turn tighter as it continues in the turn.  The vehicle will "dive" into a turn and evince a tendency to get "sideways" in turning.   Steering with be nervous and unstable require constant correction with the steering wheel.
 
Wikipedia's article on the subject:
 
When an understeer vehicle is taken to frictional limits where it is no longer possible to increase lateral acceleration, the vehicle will follow a path with a radius larger than intended. Although the vehicle cannot increase lateral acceleration, it is dynamically stable.
 
When an oversteer vehicle is taken to frictional limits, it becomes dynamically unstable with a tendency to spin out. Although the vehicle is unstable in open-loop control, a skilled driver can maintain control a little past the point of instability with counter-steering. However, at some limit in lateral acceleration, it is not physically possible for even the most skilled driver to maintain a steady state and spinout will occur.  [ http://en.wikipedia.org/wiki/Oversteer ]
 
Over-tightening WD spring bars will transfer an excess of trailer tongue weight forward onto the truck's front axle.  It will act to slightly stiffen the trucks steering and increase the understeer condition.  It will increase the resistance to turning.   Not all that great, but not a major concern.   
 
The opposite, under-tightening the bars, will shift the tongue weight back onto the rear axle and increase the oversteer tendency.  This will significantly increase the instability of the tow.   That is a really major concern.   In towing a trailer, oversteer is not our friend.   8)

Well said and spot on sir.
Regards, Bruce, Lin An & Kenji
2014 Northwoods Snow River 246RKS
Hensley Arrow Hitch
2012 Ram 1500 Hemi Sport Red (Clifford)
2013 Aliner Expedition, gone but not forgotten.

Carl L

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Re: Do I need sway bars?
« Reply #22 on: August 01, 2012, 10:00:33 PM »
Reason why I asked because 99% I'm dry camping with my RV. Now I know my water tank is 50 gallons and located back by the rear bumper of the trailer. So when I left the house it was a bit squirrelly at times. Then one trip I let the bar down to the last chain link and WOW! Huge difference it drove very controlled and very solid. My Truck is already got the Camper Special suspension on it. So even without my WD bars it sits nearly level.


50 gallon water tank back by the rear bumper!  :o    That is the least wonderful trailer design that I have seen in recent years.  The fresh tank belongs ahead of the trailer axle where it can contribute positively to balance.
Carl L/LA   [Forum Staff]  KI6SEZ

Prowler 23LV TT pulled by a '95 Ford Bronco

BigDfromTN

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Re: Do I need sway bars?
« Reply #23 on: August 02, 2012, 12:56:17 PM »
50 gallon water tank back by the rear bumper!  :o    That is the least wonderful trailer design that I have seen in recent years.  The fresh tank belongs ahead of the trailer axle where it can contribute positively to balance.

I dont recall the gallons but my Fresh water tank is in the same position.  Grey tank is above rear axle and Black tank just behind it.

I can see the need to possibly adjust the links based on the tank being full or empty.

Mopar1973Man

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Re: Do I need sway bars?
« Reply #24 on: August 02, 2012, 09:34:31 PM »
Yea... 50 gallons at the trailer rear bumper. Exactly like Carl L  ::)

But it's odd if I set the WD bar up the same way the dealer set it up it feels squirrelly or get sway easy. But now let up 1 link (last link) in the WD bars the rear axle springs of the truck squat slightly and the truck feels much more stable. Why? I'm not sure. (Puzzled Smiley here)

Mopar1973Man (AKA: Michael Nelson) located out in the state of Idaho with...
2002 Dodge Ram 2500 5.9L Cummins Turbo Diesel
2000 Jayco Eagle FBS 296
http://articles.mopar1973man.com/members-rides/17-mopar1973man/27-2000-jayco-eagle-296-fbs
2013 BigTex 70TV Utility Trailer

BigDfromTN

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Re: Do I need sway bars?
« Reply #25 on: August 03, 2012, 11:59:59 AM »
Yea... 50 gallons at the trailer rear bumper. Exactly like Carl L  ::)

But it's odd if I set the WD bar up the same way the dealer set it up it feels squirrelly or get sway easy. But now let up 1 link (last link) in the WD bars the rear axle springs of the truck squat slightly and the truck feels much more stable. Why? I'm not sure. (Puzzled Smiley here)

Because you are putting some weight back on the tongue would be my guess.  ????
Weight that was removed by the extra weight at the rear of the trailer which uses the axles as a fulcrum (described earlier by other poster).  Thats my un educated guess!!!

Gary RV Roamer

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Re: Do I need sway bars?
« Reply #26 on: August 04, 2012, 08:49:48 AM »
BigD is right on the money.  50 gals of water is 400+ lbs and its well behind the axle (fulcrum). That lifts at least that much weight off the tongue (actually quite a bit more), so you need much less weight compensation from the spring bars.
Gary
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Mopar1973Man

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Re: Do I need sway bars?
« Reply #27 on: August 04, 2012, 09:22:11 AM »
Thank guys (BigD and Gary)!!!  8)
Mopar1973Man (AKA: Michael Nelson) located out in the state of Idaho with...
2002 Dodge Ram 2500 5.9L Cummins Turbo Diesel
2000 Jayco Eagle FBS 296
http://articles.mopar1973man.com/members-rides/17-mopar1973man/27-2000-jayco-eagle-296-fbs
2013 BigTex 70TV Utility Trailer