Saturday, April 11, 2020

Avoid Accidents Because of Trailer Sway

"Subie vs. Barbed Wire. You can see who won this round." Photo Annie Wynn, 2020.

We plan for the expected, but sometimes that isn't enough. This was Annie Wynn's experience recently while pulling her trailer through west Texas. She could see storming in the nearby mountains, and the prediction was for winds of up to 15-20 mph, which she'd driven in before with no problems.

Wind is unpredictable, though. Mountain ridges can begin far apart and then narrow, creating a funneling effect, concentrating the movement of air, creating a blast of wind as you turn a corner while rounding a knob of ridge. Other factors can also apply, all resulting in a sudden, concentrated gust of wind sideswiping your camper and creating trailer sway. That was Annie's experience as she was negotiating her way down the road, dealing with the 15-20 mph winds--a sudden blast.
"Then the trailer started to sway. I felt it before I saw it in my rear view mirror. My right hand moved to the trailer brake and hit the panic button and I kept an even speed. I’d visualized this situation, so I knew what I was supposed to do. For a few seconds, I felt the trailer falling back in line and I thought I was going to be OK. Then what felt like a big hand hitting the back of the trailer pushed it to the right and I felt the car go left and it all went wrong."
Annie Wynn was the subject of one of Green Goddess Glamping's Tiny Trailer Owner Profiles recently, on December 13, 2019 (Annie Wynn's Wonderful World: 3 Years on the Road). She's an experienced full-time camper and also an excellent writer, maintaining her blog Wynn Worlds, where she writes about her wind experience, "Going Off the Road." The article's worth a read. It includes experienced-based knowledge, and it's also just plain compelling reading. In an email to me she said, "The tow vehicle weight/tow capacity would not have made any real difference, according to the state trooper and two deputies. They have seen many sway accidents on this road over the years, and it's random, big and small rigs have gotten blown around. The root cause is bad weather up in the mountains comes sweeping down a few passes and if the winds are strong enough, they hit that section of road with no warning, and no visibility."

Reading Annie's article motivated me to research more about the subject of loading your travel trailer, hitches, and trailer sway. I decided to go to experts for my online advice, so I chose insurance companies, hitch manufacturers, and trailer rental companies for my information base. Below is a compilation of the information I gleaned, plus a couple of videos and some links to excellent additional information.

At this point, it might be good to provide a video of an actual towing "sway" or "whipping" event.

A good introductory article, "Trailer Towing Tips: How to Prevent Trailer Sway," is available at the Nationwide insurance company's website. The article includes a brief description of what causes trailer sway.
"Any trailer towed with a hitch set behind the rear axle of the tow vehicle can sway or fishtail while driving. The hitch acts as a pivot point in-between the centers of gravity of the two vehicles. Any trailer sway or side-to-side force will turn the vehicle and create an unexpected steering force. If that sideways force is strong enough, it can be more powerful than the road-tire friction for the drive wheels on the vehicle. This can cause the tipping over or separation of the trailer and maybe even the truck or car too."
The article continues with more explanation that sway can be exacerbated by trailer weight, balance, and weight distribution problems. The Nationwide article also links to an RVTravel article that further mentions how a poor match-up of trailer and tow vehicle can also cause sway problems, along with wind gusts caused by terrain or by large semi trucks.

Every article I've read stresses the necessity of having enough weight forward a trailer's axle so that the majority of the weight of the trailer load is to the front. From what I've read, the tongue weight of the trailer should be 10-15% of the trailer weight, or some say the trailer's load distribution between front and rear of the trailer should be a 60-40% ratio, with 60% forward of the axle. A concise article by Fastway summarizes this information.

Weight distribution is vital, and you have to be aware of how you are loading up your rig. This includes freshwater tanks and holding tanks--where are they situated on the trailer in relation to the axle? Are the holding tanks full and the freshwater tanks empty? The video below demonstrates the important of having a properly balanced distribution of weight front to back.

The Nationwide article includes a list of tips from the National Highway Traffic Safety Administration (NHTSA) for lessening the possibility of trailer sway.
  • Use the manufacturer recommended gear when towing.
  • Slow down. Moderate driving speeds produce less strain on your vehicle and trailer reducing the chance for trailer sway.
  • Don’t make any sudden steering maneuvers.
  • Release the accelerator and keep a firm grip on the steering wheel to control sway caused by large passing vehicles.
  • Check the tire pressure. Under-inflated tires reduce the load-carrying capacity of your vehicle or trailer, which can cause sway.
The NHTSA recommendations for dealing with trailer sway are basically four actions, which Annie mentions in her accident account and which are mentioned in later articles: let off the accelerator, activate manually the trailer brakes (Annie's "Panic" button), don't use the tow vehicle's brakes, and keep the tow vehicle's steering wheel straight ahead.

The most comprehensive article I found on setting up your tow rig, loading your trailer, and towing safely was on the U-Haul website, "Trailer User Instructions." The article is comprehensive and uses good titles to provide information in a clear manner; therefore, I'm not going to try to duplicate the information in this article. Providing overall topics on the U-Haul towing instructions page should provide an incentive, though. The article defines "whipping" and "swaying," how to load a trailer, how to drive, weight distribution, hitches, and maintenance. You should read this article. However, at the risk of contradicting myself, here is a brief list regarding "combination disturbances." Capital letters usage is used for emphasis by the U-Haul site.
  • A “combination disturbance” is improper handling, whipping, sway, over-steering or other deviation of the tow vehicle or trailer from their intended path, due to one or more causes (improper loading, steering inputs, excessive speed, cross winds, passing vehicles, rough roads, etc.).
  • If a combination disturbance occurs:
  • Let off the gas pedal. NEVER speed up to try to control a combination disturbance.
  • DO NOT apply your brakes.
  • HOLD THE STEERING WHEEL in a straight-ahead position. DO NOT try to control the combination disturbance by turning the steering wheel.
An area that I am still learning about has to do with equipment, namely weight distribution hitches and sway bars. When I buy my new trailer, a lightweight Safari Condo Alto, the company recommends a weight distribution hitch with sway bars. The new hitch system will be installed at the travel trailer factory when I pick up the trailer. Some Alto owners have questioned whether the trailer, with its 1,867-pound dry weight, really needs the system. My Nissan Pathfinder tow vehicle has a towing capacity of 6,000 pounds and a tongue weight capacity of 600 pounds. I've chosen to err on the side of caution, though, and plan to include the weight distribution hitch with my purchase, and to have the Safari Condo factory team match up my trailer with my vehicle.

I do know that when towing my little standy trailer over the Appalachian Mountains last summer, there was one point when descending on a 12% grade and rounding a shoulder of a mountain, I wondered if the centrifugal force of negotiating the turn, combined with a gust of wind while edging around the mountain, would put me in danger. Annie Wynn certainly found herself in such a situation. Small decisions can matter. I do notice, for instance, that my trailer seems a bit more stable if I store my Yeti cooler in the camper door entrance walkway (in front of the axle) rather than storing the cooler in the back of the car. This is especially true if I have my bicycle rack and bicycle mounted on the back of the trailer. I intend, finally, to make friends with a large, established RV sales center in the town next to me. I'll be able to go there and have my weight distribution/tongue weight determined, which will provide me with some concrete data to use when loading up.

The towing equipment company, etrailer, lists on their website common questions and answers relating to weight distribution hitches. Below are the questions the etrailer article answers.
  • What is a Weight Distribution Hitch, and How Does It Work?
  • When Do You Need a Weight Distribution Hitch?
  • Does a Weight Distribution Hitch Increase Towing Capacity?
  • Can Weight Distribution Be Used with Surge Brakes?
  • What Are the Components of a Weight Distribution System?
One last hitch system and trailer brake safety feature I've run across relates to the placement of where on the tow vehicle the release cable should be secured. One article pointed out that securing the release cable to the hitch receiver (typically where the chains are connected) won't work to activate the trailer brakes on a disconnect from the tow vehicle if the receiver connector breaks off. The article takes a while to get to the point (to heighten suspense, I suppose) but does eventually show photos of the weld breaks and the unreleased trip cable. (Article from Camp Addict.)

My feeling is that if a trailer "whipping" event can happen to Annie Wynn, it can happen to anybody. Her cool-headed reaction to the event, which included activating her trailer brakes (she had practiced that maneuver in case it would ever be needed), minimized the danger and damage caused by the accident. Annie is taking this moment to replace her Suburu for a Honda Ridgeline, something she had planned to do anyway a year from now. "It's not because I don't think the Subaru is not a good tow vehicle. It's fine, especially for people who do occasional trips. For a full-timer though, I was always struggling with stowing stuff and then having to empty it out if I wanted to take passengers somewhere. The Ridgeline has almost twice as much storage space and can handle longer, bulkier objects better. So rather than wait a year, I am switching vehicles now."

Annie also added in her email a description on a driving experience that happened after the accident, involving her hood flying open while towing at 55 mph.
"There is an aftermath to the accident that I had not anticipated, and that was that what looked 'fine' was not in one important case: the hood latches. Eight hundred miles after the accident, driving on I-10 in a construction zone that was really bumpy, the hood latches released and the hood went flying up against the windshield as I was going 55 mph and towing. The hood had been opened and closed three times since the accident, with the usual solid thud as it slammed shut, so I had no reason to think it was damaged. But it was. So I guess the takeaway would be that after an accident, a complete car inspection would be my recommendation. I had the car up on a lift twice after the accident (check and tire fixed the day after, and wheel alignment a week later when I found a place to do it since I could feel the wheels were off) but no one, including me, thought to do a full check of everything. Maybe a Subaru mechanic would have spotted it, but their 17-point check doesn't include hood latches, either. So who knows if anyone would have caught it before the hood unlatched at speed."
As usual for me, I learn by interaction with experience and through research. Learning about trailer sway and how to handle it is just one more step in my growth as a tiny trailer owner. I'm thankful to all individuals and websites that added information for this article. Safe travels to everyone!

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  1. Replies
    1. Thank you! I learned a lot from researching and writing it.

  2. Great information. Something we all need to keep in mind when traveling.

    1. I'm a cautious driver, but researching this article was a real incentive for me to never drive too fast, especially while towing.

  3. Wow, wow, wow. That video of the swaying and overturning trailer made my heart stop. This is important information, thank you for sharing. Kind of makes me nervous, though, of every pulling a trailer of my own some day.

  4. If you substitute "nervous" for "cautious," then I think the task of learning to tow becomes manageable.