# Sway



## ED_RN (Jun 25, 2006)

On our last trip I noticed some sway when trucks (tractor/trailers) were passing me on the left. It wasn't bad but I definately had to grip the wheel a little tighter and pay more attention. Me passing trucks with them to the right was a whole different story. The end of the trailer would jerk to the right just as it started to clear the trucks trailer. My brother in law was behind me and called to say the TT had almost hit the mirror of the truck I was passing. 
My questions: I have a Reese weight distrubutuion hitch and a standard single friction type sway bar. Will tightening up on the sway bar help? I think I can add a dual cam setup to my existing set up and dump the friction bar, will that help? Should I change the entire set up? Am I just stuck because of my TV?


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## CamperAndy (Aug 26, 2004)

The dual cam will improve things but that said the trailer should not dance that much even without a sway control. Are you 100% sure the trailer loading is okay and the weight distribution is correct. If you are tongue light it will react more to the outside influences of passing vehicles.

Also how fast are you going when you are passing?? It may just be you were wanting to go too fast.


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## ED_RN (Jun 25, 2006)

CamperAndy said:


> The dual cam will improve things but that said the trailer should not dance that much even without a sway control. Are you 100% sure the trailer loading is okay and the weight distribution is correct. If you are tongue light it will react more to the outside influences of passing vehicles.
> 
> Also how fast are you going when you are passing?? It may just be you were wanting to go too fast.


I have to admit I haven't checked the weights yet. Will get to the scales next week. Also had in laws in the TV which is not usual. The speeds were usually slow around 50-55 mph. I only passed on a couple of steep grades were the simi's were really going slow.


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## PDX_Doug (Nov 16, 2004)

Ed,

There can be a couple of things in play here. First, the sway control may not be properly adjusted and/or the trailer weight distribution may be way off. Both can be remedied with careful weighing of the rig. The standard friction sway control you have is really not that great though, and if it were me, I would upgrade to the dual-cam sway control on your existing hitch.

The second issue is recognizing what is and is not sway. When you pass - or are passed by - a large vehicle, such as a semi, a low pressure area is created between the two vehicles that tries to suck the two together. You, being the smaller of the two, feel the brunt of this. It can be unnerving, and dangerous, but it is not sway. Generally this can be recognized because both the TV and TT will try to move towards the truck as a unit. The rear of the trailer lurching towards the semi is also an example of this. As you were passing the semi, you were correcting for the low pressure effects by steering slightly away from the truck. Kind of 'crabbing' just a little bit. You may not have been doing this consciencely, but you were. Then, as your Tundra broke through the aerodynamic bow wake of the semi, you again corrected the steering to straighten yourself out in the lane (else, you would have driven off the left side of the road!). The rub is, for a brief period of time, the Outback was still in that low pressure area, and because you were no longer crabbing away from the truck, it tried to suck in to it.

The solution to this effect is to 1) move as far to the opposite side of your lane as possible to increase the distance between the vehicles, which will in turn lessen the low pressure differential, and 2) reduce the difference in your passing speed relative to the semi. This also will lessen the low pressure effect.

Hope this helps.









Happy Trails,
Doug


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## cookie9933 (Feb 26, 2005)

Doug,

Very impressive explanation!







Have you been taking a class in aerodynamics? Again, this forum shows the wealth of knowledge available.

Bill


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## LarryTheOutback (Jun 15, 2005)

PDX_Doug said:


> When you pass - or are passed by - a large vehicle, such as a semi, a low pressure area is created between the two vehicles that tries to suck the two together.


This effect is quite obvious when Ellen is driving. You can hear her say "Push Push Push, Suck Suck Suck" under her breath as the truck pushes us away then tries to suck us in. I guess it's her way to remember to stay calm, and that this too shall pass.

Ed


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## ED_RN (Jun 25, 2006)

PDX_Doug said:


> Ed,
> 
> There can be a couple of things in play here. First, the sway control may not be properly adjusted and/or the trailer weight distribution may be way off. Both can be remedied with careful weighing of the rig. The standard friction sway control you have is really not that great though, and if it were me, I would upgrade to the dual-cam sway control on your existing hitch.
> 
> ...


Thanks Doug. Maybe I'll just go back to pulling a tent trailer. Just kidding won't give up my Outback. I'll defintly try the dual cam system. Also try your other suggestions.

Chris


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## sircarryalot (Jun 23, 2005)

cookie9933 said:


> Doug,
> 
> Very impressive explanation!
> 
> ...


That was Doug's beagle answering the question!!!









Strikey Mikey


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## Hokie (Jul 10, 2006)

Ed,

I have the nearly the same setup as you (except different hitch) and have not had any problems at normal speeds around 60-65. I even took it up to 85 once (for a brief time to pass) and everything was steady as a rock. The Toyota Tundra double-cab has a very long wheelbase that really helps. As everyone else has said, you really need to check your weights and determine what is happening. My personal belief is that you need to figure out why you have sway and fix it, versus just adding friction or even dual-cab setups. Those should be insurance policies, not the absolute fix. Make sure your tire pressures are OK, make sure your tongue weight is adequate, make sure your tongue is not higher than the rear of your trailer, and take a trip to the CAT scales to really get a measurement. Do this no matter what. But as Doug says, maybe you are just experiences the gentle pull and pushes of semis, that defintely happens to me, usually when I am driving along and don't realize a truck is coming up my side. I feel the pull on the steering wheel and then look in my mirror.

Good luck, and get to the scales!

-Sam


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## egregg57 (Feb 13, 2006)

When I was towing with my half ton, I added a bit of water to the fresh water tank (ours is in the front) it all but eliminated the remaining sway.

Then I got my F-250 XLT 6.8L V-10. Now Tractor trailers sway as I pass them. heh heh heh!


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## PDX_Doug (Nov 16, 2004)

egregg57 said:


> Now Tractor trailers sway as I pass them. heh heh heh!


Eric,

That's just the drivers diving for the shoulders in terror when they see you approaching in their mirrors!









Happy Trails,
Doug


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## egregg57 (Feb 13, 2006)

PDX_Doug said:


> Now Tractor trailers sway as I pass them. heh heh heh!


Eric,

That's just the drivers diving for the shoulders in terror when they see you approaching in their mirrors!









Happy Trails,
Doug
[/quote]

Absolutely!!







err. I think....wait a minute I detect sarcasim!!


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## 2500Ram (Oct 30, 2005)

PDX_Doug said:


> The solution to this effect is to 1) move as far to the opposite side of your lane as possible to increase the distance between the vehicles, which will in turn lessen the low pressure differential, and 2) reduce the difference in your passing speed relative to the semi. This also will lessen the low pressure effect.
> 
> Hope this helps.
> 
> ...


Very good advice I read on here just over a year ago, maybe it was even Doug that wrote it then. I hug the outside or inside of my lane when passing a semi or being passed by a semi. The only time I cringe is if I'm on a 3 lane hwy in the middle lane and being passed by a semi on each side







not fun no matter what sway control or TV you have. The TT is just a big sail and will be sucked in.

Being you already have the Reese setup I'd get the duel cam HP setup, I didn't know any better and the dealer threw in the duel cam HP setup when we bought our TT used and I've never looked back, I love the extra control it offers. I only towed our 26rs once without the bars on and I'll never do that again even with our 3/4 ton diesel, too much bounce for my comfort at speed.

Good luck and keep us posted.

Bill.


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## N7OQ (Jun 10, 2006)

I have seen posts about this before but every time I get passed by large semi's I never feel a thing. If they a passing me real fast light a car going 90 and me going 40 I might feel a tick tick in the wheel but no push or pull. Maybe there is a difference between using a SUV vs a Truck as a TV.


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## beanfarmer (Jul 26, 2005)

I had the same experiance. I took the friction bar off and threw it in the scrap bin and added the dual cam. I now travel much more at ease and don't fear passing trucks.


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## Katrina (Dec 16, 2004)

I'll bet anything the tongue of the TT is too high.
Check that the TT is level or slightly nose down.
After you get the dual cam that is.


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