It was hard to watch

I as on I95 this afternoon. Damp road from an earlier rain. A nice, late model Chevy pick up, full size 4 door, passed me towing what looked like a race car trailer, 24' or so. A few miles further and I was catching up with him. Then I noticed the trailer start to sway. Minor at first, but within 15 seconds it went to major, all over the road, scary. Then he jacknifed, sliding off the road to the right. I heard a very loud "snap", the front end of the truck came about 2 feet off the ground, and it came to a stop. Amazingly, on I95, nobody hit him. I have driven thousands of miles towing race car trailers, almost all of them crappy, and never came close to having this happen. What causes it? What can you do to stop it from progressing once it starts?

In my experience it usually happens because the load isn't properly distributed. (too far front, or back)

Whenever I get the "sways" when I'm towing, I'll hit the gas, to pull through the sway, and then slow it down gently.

scary stuff!

Joe Gearin wrote: In my experience it usually happens because the load isn't properly distributed. (too far front, or back) Whenever I get the "sways" when I'm towing, I'll hit the gas, to pull through the sway, and then slow it down gently. scary stuff!

+1 ease into the throttle or hit the trailer brakes if you have them. Once I went to a dually the sway is much easier to manage when/if it happens, but only because you have more of a chance to correct before it really starts moving the truck.

This happened to me once on a smaller scale. I was towing my mini to my first event with a borrowed ford ranger. Single axle trailer, with weight too far back. Swayed enough to put the trailer tires in the air on the sways. Scary. I was able to accelerate out of it, and quickly slowed back down and got off the interstate. Thankfully I had used about 8 tie downs to put the car on the trailer, so it all stayed together nicely. I was able to fix the issue with more weight forward on the trailer.

We watched an RV trailer pull this stunt years back coming down the Siskiyous. It started swaying, we all hoped we wouldn't see the brakelights but we did and that was that, it flipped on its side, almost rolled the truck, I vividly recall the house batteries continuing down I5 for quite some distance...

I live in the mountians (the smaller more easterly ones) and was wondering..

what is the plan if you start swaying when going down a (BIG)hill?

I tend to avoid towing because the stories of this make me uneasy. I had a bad enough time dealing with a uhaul trailer on a F150xlt crewcab (although its trailer brakes were SHOT with a duct taped master and the tires were dry rotted and the worst sway was attributed to one out of the 4 tires having disintegrated) (NEVER RENT UHAUL!)

Joe Gearin wrote: In my experience it usually happens because the load isn't properly distributed. (too far front, or back) Whenever I get the "sways" when I'm towing, I'll hit the gas, to pull through the sway, and then slow it down gently. scary stuff!

A flat rear tire on the truck will cause a lot of drama too.

Instead of hitting the gas when I get the wiggles I usually thumb the trailer brakes a little... but I've found that the best way not to get them at all is to load up the static tongue weight by putting the car as far fwd as I can. That seemed to cure 90% of the ills.

I once came upon a travel trailer that had flipped over on it's side on an interstate. I don't know what had caused it but it literally exploded as it went over and it's contents were spread all over the road for what seemed like a half a mile or so. The family was out trying to pick up some of their belongings. Clothes, food, pots and pans you name it.....all across the road.

been there, done that.. When towing a trailer, I always accelerate SLOWLY to both the speed I want to go and then to about 10 above for a just in case.. by taking care and feeling for what the car and trailer are doing, you can back out as it begin to sway and then stop and redistribute.

I use the bail out door on the left of the trailer as a guide. When the car door opens into the bail out door, it's far enough. The tool box and the spare tires are also in the nose of the box. It's all about tongue weight.

A good friend of mine loads his trailer thusly: he loads whatever on the trailer then moves the load forward till there is a slight down hill tilt (maybe 1 degree) toward the hitch. He's never had a problem.

I have to wonder about how to fix the downhill sway thing as well. Assuming there were no trailer brakes, the only thing I can think of, ride it out and do NOT try to brake. With a trailer brake controller, I'd say don't touch the tow vehicle brakes but ease the controller slide over, slowly feed power to the trailer brakes.

its pretty simple, guys. find something thats 500lbs, and put it in the bed. with that load in the bed(as far back as it can get, nothing hooked to the truck) measure the height in inches from the hitch to the ground. now you load the trailer (remove the 500lbs from the truck) until you get the same measurement. now you have a 500lb tongue weight, which is the accepted load value of a class 2 hitch. do this, and you should have FAR less issues with towing.

add to that equal air pressures all 4 corners, trailer too, and not mixing size/brand tires on the trailer, good brakes, and proper driving and braking procedures, and youll likely never have an issue.

-J0N

there's an equation relating the position of the trailer load and the speed at which any steering input will induce sway. i don't know the equation, i'm just saying that it's out there. google probably knows it.

anyway, one of the last products i got to test at TRW was the "trailer sway control" feature of our vehicle stability control system. by monitoring yaw rate, lateral acceleration, and steering wheel position, it can tell when the tow vehicle is being "forced" by the trailer, and times the individual corner brake applications to scrub speed while stabilizing the oscillations.

closed course, professional driver, don't try this at home, etc. it was a bad-ass demonstration how sometimes technology is our friend. i'd still rather have a properly loaded trailer, but trailer sway control is friggin cool nonetheless.

Jensenman wrote: With a trailer brake controller, I'd say don't touch the tow vehicle brakes but ease the controller slide over, slowly feed power to the trailer brakes.

+1, although getting the tongue load right and having a straight trailer helps a lot. My buddy bought a $500 20' open job that wouldn't tow straight for anything and gobbled up tires. Turns out the axles weren't parallel.

I hate to see a truck and trailer piled up on the side of the road. Unfortunately it happens a lot. Inexperience in loading and towing a trailer can end up badly. Towing with too small vehicle will also cause problems. When the trailer out masses the tow vehicle the tail can end up wagging the dog.

To correct sway I usually hold the steering straight and let off the gas. Also when towing at interstate speeds I turn the gain and power on the trailer brakes to max. That way when you need to slow down, the trailer brakes first and hardest and you don't have to find that little lever to to engage the trailer brakes. It also makes emergency stops much safer.

Bumper pull trailers should have 10-15% of the trailer weight on the tongue. To little tongue weight causes sway. To much causes bucking and makes steering vague. A 5000# trailer should have 500-750# of tongue weight. Where you load depends on where the axles are located and how much tongue weight the trailer has empty. My enclosed trailer I end up loading the car as far back as possible to get the tongue weight right. My open trailer I end up loading with the car centered over the axles. My utility trailer I ended up moving the axle back 6" because it was impossible to load right. Tongue weight is critical. If in doubt, too much tongue weight is less dangerous than to little. If you get it right, you can almost forget the trailer is behind you. It will drive and ride good with little to no sway and you won't feel like you are about to be thrown out of the drivers seat. You also won't have to worry about how to correct sway.

Copied off another site.

TYPE OF TRAILER

PERCENT OF WT. ON TONGUE

Single Axle 10% minimum/15% maximum

Tandem Axle 9% to 15%

Travel Trailer 11% to 12%

5th Wheel 15% to 25%

If you are towing a trailer with a car onboard, the weight distribution of the car makes a difference. A fwd car will have to be farther back than a rear engine car.

Towing is without a doubt the most dangerous part of the car hobby. My shortest tow to a track is 4 interstate hours so we have had all sorts of adventures and experiences. My main advice is that you need excessive tow capacity in your tow vehicle. Good balance on the trailer is a must. Unfortunately you will never wear out a set of trailer tires; they will dry rot first. Remember that the trailer needs just as much maintenance work as the tow vehicle.
My mantra is that I dont want to make the headline of newspaper for "racing lawyers defective trailer kills family of five"

It happened to me once and I tow ALOT. I just gently accelerated while gently applying the trailer brakes. Came right back in line.