Friction sway - loosen when raining?

[Skater]

Someone else mentioned getting this advice, too. Anyone know why that is? I can't come up with a good reason.

Seems like you want sway control in rain even more...

(Please, no hitch brand arguments in this thread. Thanks!)

[ROBERTSUNRUS]

Hi, I have driven/towed in all kinds of weather, rain, wind, snow, ice, zero degrees, and over 100 degrees. I have never changed anything related to my hitch for any of these, but I did reduce my brake controller while towing on icy roads.

[Bruce B]

I assume this advice has to do with the Andersen hitch?
I would begin by asking the manufacturer "Why?" and see what they say...
Bruce

[markdoane]

Doesn't apply to Anderson any more than any other friction sway control.
The effect of friction sway control is to stiffen the joint between the trailer and the tow vehicle. On slippery roads, and especially if weight control isn't set up well, it can cause understeer condition when going around curves.
I don't have proof, just a theory.

[AWCHIEF]

Originally Posted by Bruce B

I assume this advice has to do with the Andersen hitch?
I would begin by asking the manufacturer "Why?" and see what they say...
Bruce

Why would you "assume" this? As an Andersen owner and user your assumption makes no sense to me at all based on its engineering design.

[Bruce B]

Originally Posted by AWCHIEF

Why would you "assume" this? As an Andersen owner and user your assumption makes no sense to me at all based on its engineering design.

The Andersen hitch was the only hitch that uses a brake type friction control and It seems to be the only hitch where sway control might be impacted by tension adjustment.
After watching the video on the Andersen site and I wondered if the change in coefficient of friction that most sway systems use might be more tuneable with the Andersen (therefore hey recommend a change for different conditions????). You can't change the tension on an Equalizer and I am not sure how the Reese dual cam is adjusted but it doesn't appear that a change in tension would affect that designs friction by much as it appears to be more a function of shape of the bars there ????

I am not slighting the Andersen, just wondering....

Are you sensitive about this subject? No disrespect intended!

Originally Posted by markdoane

Doesn't apply to Anderson any more than any other friction sway control.
The effect of friction sway control is to stiffen the joint between the trailer and the tow vehicle. On slippery roads, and especially if weight control isn't set up well, it can cause understeer condition when going around curves.
I don't have proof, just a theory.

I am trying to get my head around this thought and perhaps you are correct but wouldn't the impact of lowering the tension in most hitches also lighten weight distribution thus also creating a lighter front axel that would be more likely to push or understeer?

Just wondering.....
Bruce

[Skater]

I wasn't thinking about the Andersen, but about the traditional friction sway bars such as Reese.

Originally Posted by ROBERTSUNRUS

Hi, I have driven/towed in all kinds of weather, rain, wind, snow, ice, zero degrees, and over 100 degrees. I have never changed anything related to my hitch for any of these, but I did reduce my brake controller while towing on icy roads.

Totally agree with the controller adjustment advice, but I also add rain - we don't want the trailer's brakes to lock up.

[n2916s]

This applies to the old school friction anti- sway assemblies. Essentially a sliding armature encased in brake material. The instructions that came with mine required that the tension (and therefore the rigidity) of the apparatus be backed off in rain or snow.

No explanation offered but a reasonable assumption is that too rigid a connection along with a low coefficient of tire/ road friction would lead to under steer.

I always did it but never noticed any difference.

Mike

[markdoane]

Originally Posted by Bruce B

I am trying to get my head around this thought and perhaps you are correct but wouldn't the impact of lowering the tension in most hitches also lighten weight distribution thus also creating a lighter front axel that would be more likely to push or understeer?

Just wondering.....
Bruce

No, you're not lightening the tension on the spring bars. What "loosen" means in this context is to loosen the clamping force on the anti-sway bar.
Two different adjustments.

[Skater]

Just found this in the Reese manual:

When towing during slippery conditions such as wet, icy, or snow-covered roads or on loose gravel, turn on/off handle (5) counterclockwise until all tension is removed from unit. Failure to do so could prevent tow vehicle and trailer from turning properly.

Interesting...

[Bruce B]

So,
It sounds like they are concerned with understeer as a result of the friction force of anti sway.....Hard to imagine that these hitches could generate enough force to impact the steering of the tow vehicle but then again the noise my Equalizer made when turning at slow speed was pretty amazing!
Interesting indeed!
Bruce

[Skater]

Originally Posted by Bruce B

So,
It sounds like they are concerned with understeer as a result of the friction force of anti sway.....Hard to imagine that these hitches could generate enough force to impact the steering of the tow vehicle but then again the noise my Equalizer made when turning at slow speed was pretty amazing!
Interesting indeed!
Bruce

Yeah. Frankly I'd rather deal with a risk of understeer instead of an increased risk of sway. But the way it's worded made me think they are thinking of low speed situations in parking lots, rather than highway driving.

[AWCHIEF]

Bruce, no offense or whatever taken. All "opinions" are always welcome.

[markdoane]

Originally Posted by Skater

Yeah. Frankly I'd rather deal with a risk of understeer instead of an increased risk of sway. But the way it's worded made me think they are thinking of low speed situations in parking lots, rather than highway driving.

You're reading more into it than what was written.

[TG Twinkie]

The idea behind the conventional sway (friction bar) is to increase the force required to move the trailer tongue in a horizontal direction. Thus preventing or at least reducing sway.
Which is logical for towing on straight roads.
But, when towing on curving mountain roads. The logic IMHO falls apart.
Look at it this way. On a straight road the friction type sway bar keeps the trailer straight behind you.
When on a curvy mountain road. You must steer hard enough to overcome the friction of the sway bar in order for the trailer to move out of the straight line to follow the curve of the road. Now the trailer has moved sideways to follow the curve of the road relative to the TV.
So now the sway bar wants to keep the trailer on that arc.
In order to straighten the rig out or go into the other half of a "S" curve. You have to steer hard enough to overcome the sway bar friction.
If there is enough friction in the sway bar mechanism to keep the trailer from moving sideways or swaying. There is enough friction to prevent the trailer moving back to a straight line behind you.
I believe any anti sway device places abnormal side wall pressure on the Trailer tires. Since their purpose is to keep the trailer from moving in an arc relative to the TV.
It would be akin to having a set of tires half way between your elbow and wrist. Then locking your elbow in a straight line. Now swing your arm in a horizontal arc from the shoulder. The tires are forced to slide side ways until the friction of the sway bar is overcome.
This force is the same when going into a curve or coming out of a curve.
The force required may be enough to affect the steering of the TV. Especially on gravel, wet or snow covered roads.

[MrUKToad]

If you're using the traditional anti-sway friction arm then advice to loosen it off in wet or icy conditions will be to do with the relative friction between the tires and the road on both sides of the friction arm (TV tires and trailer tires).

In order to overcome the forces of the friction arm when moving in anything other than a straight line, you're going to need the tires on both your TV and your trailer to be making good contact with the road. If there isn't sufficient contact, the friction arm forces won't be overcome and the TV, the trailer, or both, can be put into a situation where the tires prematurely lose contact with the road altogether and you're in a skid before you know it.

That said, I use two friction arms and have never loosened them at all in heavy rain and (thankfully) have never had a problem. Were the conditions obviously slick, like in snow or on ice, I may well get out and loosen the friction settings. I guess it's a bit like not using your cruise control in the wet.

[Inland RV Center, In]

Torsion arm sway controls are always in use, without any adjustments, for sun, rain, or snow.

They always work.

Andy

[Ron Gratz]

Originally Posted by MrUKToad

If you're using the traditional anti-sway friction arm then advice to loosen it off in wet or icy conditions will be to do with the relative friction between the tires and the road on both sides of the friction arm (TV tires and trailer tires).

It is correct that some friction sway bar manufacturers say to loosen the bar when towing in reduced-traction conditions.

The thing that puzzles me is -- why don't the Equal-i-zer and Dual Cam manufacturers give warnings about using theirt hitches in low-traction conditions? The EQ and DC generate several times as much resistance to straightening as does a friction sway bar. Therefore, if it is dangerous to tow in reduced-traction conditions with a friction bar, it should be several times more dangerous to tow with the EQ or DC.

It is correct that the bar will resist allowing the trailer to return to normal. However, I believe many people over estimate the magnitude of the effect.

The most commonly sold friction bar SC (FSC) is factory-set to produce a yaw-axis torque of about 500 lb-ft. A 25' TT will have a distance of about 18' from ball to axles. This means the FSC torque would equate to a lateral force of about 28# at the TT's tires. On dry pavement, if a 6,000# TT swings to an angle of 1 degree, its tires will develop a lateral restoring force of about 500#. The TT would need to have an "off tracking" angle of only about 0.06 degree to balance the FSC torque. On snow or ice, the angle might increase to about 0.2 degree.

For comparison, an angle of 0.06 degree would result in the rear end of a 25' TT being out of line by about 0.35".

Some people also over estimate the magnitude of added steering force required to overcome the torque generated by the FSC.

If the 500 lb-ft of torque is applied to a TV with a 120" (10') wheelbase, the front tires must generate a lateral force of 50# to counteract the torque. If the front axle is carrying 3000#, the tires must be turned about 0.15 degrees on dry pavement to generate a lateral force of 50#. Required increases in steering angle for other surface contitions might be: wet pavement = 0.2 degrees, packed snow and dry ice = 0.3 degrees, glare ice = 0.55 degrees.

So, yes, a friction bar SC can induce some "understeer". However, the added steering angle required to overcome the "understeer" is relatively small compared to the maximum tire slip-angle of 5-6 degrees at which the lateral force begins to plateau. The required added angle might be so small as to be undetected by the driver.

The "stiffening" effect of the FSC might be noticed when coming out of a curve. When not towing, the the camber and toe in of the TV's front suspension will tend to straighten the steering tires. When towing with a friction-based SC, the FSC torque will tend to oppose the camber and toe in effects and reduce the TV's self-straightening.

It might or might not be possible for the TV to self straighten. However, as long as the driver is aware that it might be necessary to provide some assistance in the straightening process, the FSC torque should not cause problems.

Ron

[TG Twinkie]

I can tell you from personal experience that the anti sway bar which is bolted to the frame of my coach. Had a dramatic effect when driving on curvy mountain roads. So much in fact, that when I get on this type of road. I back the anti sway bar completely off.
Most of these roads have speed limits at or below 50mph. Because of the curves.
If your rig does not handle well at speeds below 50mph, sway bar or not. You have other problems.
I don't use the sway bar now that I have an Andersen system. Much better handling in the aforementioned conditions.

[MrUKToad]

Originally Posted by Ron Gratz

It is correct that some friction sway bar manufacturers say to loosen the bar when towing in reduced-traction conditions.


Ron

Thanks Ron, what a great explanation! Without worrying too much about the math, I think it is a lot of people's experience that you don't have to loosen off the friction control, quite probably because as you say, not too much force is needed to counter the sway bar. I guess that manufacturers are covering their behinds with their advice.