Sway Control really needed ???

JCR-1 wrote:
I suppose it can't hurt..just wondering about hard backing ..Will it do damage in a jackknife condition. Just another thing to be wary of.. Trying to keep it simple.I just cannot imagine backing up with such an extreme angle however, but many say to remove it .. PITA

As far as the sway bar goes, it seems people are replying based on experience. You should decide based on your own experience. Pull your TT down the highway and see how i feels when the big semi trucks pass you. If you don't like the feeling, use the sway bar.

As others have stated, put it on before getting underway - I stop in front of a large lot in my neighborhood to put it on and at another on the way back to take it off before backing into my space. Take it off before baqcking into my camp site as well. If it is connected, you may get lucky and it won't break things. If it is not on then you don't need to rely on luck.

Any trailer can sway, and most can cause bad control problems when they do, even to a much heavier vehicle pulling them, and TT’s are the worst… controlling sway comes from balance, and being able to maintain the balance… RV’s are not balanced side to side and often tongue weight is hard to control, and not well controlled when in motion because the axles are most often at their extreme forward position, especially done for allowing smaller trucks to pull them… WD hitches and sway control becomes much more important for RV’ because of their (poor) design…
even the flat bed with the backhoe loaded may have a high center of gravity but the weight causing the high center of gravity is carried and better centered between the tires… load control is far better and easier in a utility or on flatbed trailer… heavier loads are carried on heavier frames to be pulled by heavier trucks instead of moving the axles a inch or two forward to allow for a undersized truck to haul it…

you could go thousands of miles and not need either the WD or sway control, and when just the right conditions present themselves a catastrophic event can happen before you are even able to react to it…

any bumper loading offloads and reduces steering control to some degree and makes the TV over-steer more pronounced in reactive steering situations… a dump truck with a flat bed trailer and backhoe has a heavy load carrying hitch with the hook/ball right at the rear axle causing less steering axle off loading…


wind causes sway through instability, because the wind suddenly changes the trailers loading destabilizing it and speed and inertia takes over from there…

I think that folks need to consider the difference between "sway" and an "unstable" trailer. Sway with RVs is usually caused by cross winds or passing big rigs.

An unstable trailer can have a few causes, one of which is improper loading with a lack of sufficient tongue weight. If this occurs bad enough the trailer will be unstable.

As far as trailer dynamics go, we should probably call the NHTSA about all those heavy equipment trailers on the road without a WHD and SC. Just think of all the wide load Mobile Homes that are transported at freeway speeds without a WDH and SC. Also, what about all those semi truck trailers with the dolly. None of those have a WDH or SC.

Both the WDH and SC are great tools and need to be used as designed when the application calls for it. They aren't required on every combination as clearly pointed out above.

JCR-1 wrote:
I suppose it can't hurt..just wondering about hard backing ..Will it do damage in a jackknife condition. Just another thing to be wary of.. Trying to keep it simple.I just cannot imagine backing up with such an extreme angle however, but many say to remove it .. PITA

I havent removed mine yet and have had it at some pretty steep angles. I think its important to install using the measurements the mfg suggests. The curt bar i use didnt say anything about removing the bar to reverse.

Not really a PITA at all. It only takes a couple of seconds to remove two clips and take the bar off if you find it necessary. Most people get out and look before backing into a site and that would be a good time to take it off. In most instances, it would not even be necessary.
I certainly would not use that as an excuse to not use one!
Barney

I suppose it can't hurt..just wondering about hard backing ..Will it do damage in a jackknife condition. Just another thing to be wary of.. Trying to keep it simple.I just cannot imagine backing up with such an extreme angle however, but many say to remove it .. PITA

The only times I have ever experienced actual sway has been with small trailers. Has more to do with how the trailer is loaded, not enough tongue weight and chances are real good that at the right speed you will get sway. Light tongue combined with hitch up and odds are even greater. Does not matter how large the tow vehicle is.

Just grab a friction bar for peace of mind. Thay are less than fifty bucks and dead simple to use.

JCR-1 wrote:
On a 21 foot lite trailer do you think sway is going to be a concern?? On a bigger trailer I know it is necessary but a lightweight 21 footer. Maybe a friction bar but I cannot see that stopping any significant wiggling. The back leverage is enormous for that to do anything ?? Comments

You would really be surprised how much a friction sway control does. It really stiffens the link between the TV, and TT. However. It is not designed to stop, or prevent sway. It is NOT an anti sway device.
It is only to help you control it, once it is induced.

I see that in at east 2 posts above there is the contention that if the TV is big / heavy enough sway is not a concern. This is not correct.

Sway is resonance that is induced on the trailer that has nothing to do with the TV.

That said, if the TV is large enough, the instability is reduced vs if the TV is small. That is it. There comes a point beyond which the instability will affect the TV regardless of size. Even if the TV is steady as a rock, I am sure none of us will drive anywhere behind a trailer that is wagging side to side even if the truck is going down the road apparently dead straight.

In the final analysis, there is all likelihood that the owner will select a trailer to match the capability of the truck, so any sway induced in the trailer will affect the rig as a whole. No one will get an F450 and pull a 1200# popup.

The question is how to minimize the sway. The place to start is to balance the loading of the trailer (12% on the tongue) and then add a properly sized anti sway system.

OP - yes, you need a WD system pulling that 21' trailer, okay? Skim off some of the common points from many of the foregoing posts and you will have your answer as to why.