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-   -   Sway Question (http://www.airforums.com/forums/f238/sway-question-108726.html)

time2play 08-21-2013 04:30 PM

Sway Question
 
Coming home driving south on I-405 in Washington, our trailer suddenly swayed. Our truck (Ford F150) briefly displayed a message about "trailer sway", which the Ford F150 displays when the trailer sway control has detected trailer sway.

The sway stopped almost immediately, and didn't happen again.

It was hot in Seattle area yesterday, barely any wind, we were driving about 60mph. My husband and I both freaked out, and he swore he was never going over 55mph again.

But still....what might have caused the sway?

Thanks for your help.

reddogfox 08-21-2013 05:25 PM

What brand and model weight distribution hitch do you use? What is weighting rating of the bars?

ROBERT CROSS 08-21-2013 05:58 PM

Quote:

Originally Posted by reddogfox (Post 1343876)
What brand and model weight distribution hitch do you use? What is weighting rating of the bars?

^
X2?

Have you been to the CAT scales? The Classics are the heavyweights of the AS line. You'll need the weights to properly set up the rig.
A quality WD hitch with integral sway control is a MUST with your 30'r.
What is the load rating of your tires? C,D,E.
LT (light truck), or P (passenger).

The Ford "sway control" does nothing to prevent sway, it only activates after sway is detected. Much better to prevent it.

Bob
:blink:

putback 08-21-2013 06:13 PM

Our '10 F150 has the tow package w/ the sway control option. With our single axle safari have had this happen a couple times caused by the "bow wave" from a bus passing us on interstate highways. According Ford its normal. The anti sway system on the truck applies brake to individual wheels on the truck to self correct and flashes the message on the dash. If the is no obvious reason for the message you may want to stop by a dealership and ask them to check the computer log on the truck for a malfunction. They also told me and while an underinflated tire will show the icon an overinflated will not, and just one overinflated can cause the sway message.

time2play 08-21-2013 08:57 PM

Thanks all for your replies.

We originally purchased a 2013 28' Flying Cloud with an Equal-i-zer sway control hitch. Four months later, we traded up to a 2013 30' Classic. The hitch was transferred from our Flying Cloud to the Classic, as per the dealer's recommendation.

I have the Equal-i-zer manual, but we're not sure of the specific model. Tomorrow, we're going to check out the hitch and make sure we know the exact model so we can answer your questions. And lesson learned for us, this is something we should already have answers.

Bob, not sure about the tires. Are you asking about the truck tires?

Anyway, the trailer did sway. Not much, but it was noticeable. And the sway ended almost immediately. I "felt" the brakes - but my husband didn't apply the brakes. So the truck must done it's job and corrected the sway. But that's speculation on my part

Is there anything else we should do or know?

Thank you all again.

overlander63 08-21-2013 09:48 PM

If the truck detects sway, it will apply the trailer brakes to stop the sway, and the "sway" message will be displayed.

ROBERT CROSS 08-21-2013 10:00 PM

It's a truck but may not have truck tires.:huh:
Look at the sidewall for the size and load rating. P for passenger, LT for light truck.

You will still need to get the WD set-up and sway control adjusted properly. A trip to the scales will help a great deal. Your trailer could very well approach 9klbs loaded for camping. Overloading the tires, tongue weight, payload and or axle rating is a possibility.
It's harder to control sway when not properly set-up, made more difficult without the numbers. Load 'er up for camping and hit the scales.

Bob
:flowers:

Wazbro 08-21-2013 10:24 PM

I normally increase my TV tire pressure by about 20% over what is recommended (as the minimum pressure) on the door for towing, without exceeding the sidewall max pressure.

Higher tire pressure helps reduce sway.

willyjay 08-22-2013 12:48 AM

Sway Question
 
I suspect that the sway was likely caused by a rut in the pavement. I 405 is not in the best shape and the pavement is often broken and uneven

dkottum 08-22-2013 06:41 AM

Whatever the cause, it is impressive to see the truck's electronic anti-sway system respond to it, and immediately correct it before a sway oscillation occurred. That's what the manufacturers have been telling us.

doug

RickDavis 08-22-2013 07:16 AM

Quote:

Originally Posted by willyjay (Post 1344059)
I suspect that the sway was likely caused by a rut in the pavement. I 405 is not in the best shape and the pavement is often broken and uneven

This is likely the reason. limited sway will often be felt on roads where heavy truck traffic has worn the road, even though you often can't see the grooves.

If this remains a brief one time event I would not be too concerned.

ROBERT CROSS 08-22-2013 07:18 AM

Doug,

I thought the system activated after the sway occurred.

"Our trailer sway control feature works with AdvanceTrac® with Roll Stability Control™ (RSC®), using the sensor that measures yaw motion to determine if the trailer is swaying. If necessary, trailer sway control applies precise asymmetric braking or adjusted engine torque to help bring both vehicle and trailer under control.*"

Bob
:flowers:

Captain Hank 08-22-2013 08:07 AM

Check the tow capacity of your truck. You are towing a 9000# trailer with an F-150?

Wazbro 08-22-2013 12:05 PM

Quote:

Originally Posted by dkottum (Post 1344093)
Whatever the cause, it is impressive to see the truck's electronic anti-sway system respond to it, and immediately correct it before a sway oscillation occurred. That's what the manufacturers have been telling us.

doug

Quote:

Originally Posted by ROBERT CROSS (Post 1344102)
Doug,

I thought the system activated after the sway occurred.

"Our trailer sway control feature works with AdvanceTrac® with Roll Stability Control™ (RSC®), using the sensor that measures yaw motion to determine if the trailer is swaying. If necessary, trailer sway control applies precise asymmetric braking or adjusted engine torque to help bring both vehicle and trailer under control.*"

Bob
:flowers:

Yes, that is after sway that it kicks in, but also before oscillation.

The first movement from sway isn't normally dangerous, when sway causes oscillation (sometimes referred to as the "hospital wobble" or "death wobble" because of what often happens next) that it gets dangerous.

ROBERT CROSS 08-22-2013 01:25 PM

Oh I see...sway isn't oscillation. Then it stands to reason that oscillation isn't sway.:huh:

I see no mention of oscillation in Fords statement. TV yaw=trailer sway.
Maybe they need to check this thread and be educated....like me.:flowers:

If you can't dazzle 'em with brilliance then baffle 'em with.....:censored:

Bob
:blink:

time2play 08-22-2013 02:58 PM

Quote:

Originally Posted by reddogfox (Post 1343876)
What brand and model weight distribution hitch do you use? What is weighting rating of the bars?

I finally have some answers! We have an Equal-i-zer 90-00-1000 (1000 lg max loaded tongue / 10,000 lb max loaded trailer weight.

Quote:

Originally Posted by Captain Hank (Post 1344126)
Check the tow capacity of your truck. You are towing a 9000# trailer with an F-150?

Our Ford F150 is an EcoBoost with a towing capactity of 11,200 lbs.

We're planning on weighing our trailer tomorrow, or definitely before we take it out again.

Where is the best place to take it to be weighed? What about those weigh stations we see alongside the freeway?

Thanks again everyone for your input. I do believe it was a slight sway caused by a rut in the freeway. I-405 is in bad shape, we'll have to keep that in mind.

Thank you!!

SteveSueMac 08-22-2013 03:29 PM

Time2play - google "cat scales" and anything you see not related to kittens should've if some help :-)

Those weigh stations you see on the highway aren't always open and when they are, troopers are usually using them to spot check commercial truckers. Many truck stops have cat scales and you can weigh your trailer there. There are several threads in the forums in this topic (I think Bob provided one direct link). I love weighing the trailer (I know - geeky) but it helps me understand how subtle changes over time can make a big difference.

Bob and Doug - re: sway/oscillation - I understood Doug to be saying that the truck detected a "sway" motion and put the electronics in to gear so that initial sway wouldn't "echo" left and right multiple times (I.e., oscillate).

Do I understand that right and if so, it seems Bob is reacting to the words, not the concept - what are the correct terms (I should have searched this first - I can feel it coming...). :-)

srpuywa 08-22-2013 03:36 PM

there is a scale in Lakewood on South Tacoma Way south of 512 close to the old Costco

featherbedder 08-22-2013 05:53 PM

I do know that in sway situation applying tv brakes instead of trailer brakes will cause more sway then danger, apply power to tv while manually applying brakes on trailer, do not panic it has happened to me more than once as I pull many kinds of trailers not always set up properly but not by me but it was mandatory to move. One accident in over 40 yrs. towing, when hitch broke because of improper design, and hitch manf. absorbed all costs, and redesigned the part that broke. Bill

handn 08-22-2013 06:10 PM

I get a tiny bit of sway with my Equalizer hitch, 25 foot Safari and diesel Excursion when an 18 wheeler or Greyhound passes me at 75 mph when there is a stiff cross wind. I have a small trailer and a big truck.
The Equalizer is o.k. for normal towing but if I were to upgrade to a big trailer at or near my vehicles towing capacity, I would upgrade to a premium hitch such as a Hensley or ProPride. Any sway is too much. I would want my hitch to suppress the sway and not let it get bad enough so the vehicle corrects it. I don't want to drive at 55 mph because I am nervous about sway.


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