I want to share an experience I had that may help others avoid similar problems. The topic is fishtailing. There are some things that are known to cause fishtailing, but the subject is complicated enough that it is a poorly understood subject. I am not claiming to be an expert and what I know is not intended to be the last word. I do think that this subject is worthy of discussion in this forum because more understanding will reduce everyone’s chance of experiencing fishtailing.

I have towed for more than 100,000 miles over a 35 year period. Thirty years of this was before my first (& only) fishtailing experience. My Dad had mentioned fishtailing and the need for proper tongue weight when I was a kid. At a minimum any one who tows should know the old rule of keeping at least 10% of trailer weight on the tongue. Knowing this and doing it are not the same thing. The owner of the Sherline tabletop mills company had a bad personal experience with fishtailing and offers a scale for measuring the actual tongue weight. See:

http://www.sherline.com/scales.htm

If you are not measuring your tongue weight, sooner or later you will mis-estimate it when hauling an unusual load. If you always pull exactly the same rig, with controlled weight distribution, you may not need to measure every time, but if you have a wife who likes to collect rocks (as Lucy in “The Long, Long Trailer” movie) you may get an unwanted surprise. (How many of you in this forum knew that there was whole move about towing a trailer made in 1954?)

I will serialize my story to keep the posts manageable. Feel free to interrupt my post with comments, although holding questions until after my story is complete is probably a good idea as I hope to anticipate some of them.

 

I am a team truck driver and several months ago we almost got taken out by an idiot that started fishtailing real bad when i tried to pass him. I had to drive the truck into the median to avoid his whipping trailer from hitting us. He finally jacknifed onto the riight shoulder. He said after we went to check on him, "I guess i should have loaded some of the heavy stuff up front" Duh!~ He had insulation up front and 2 pallets of brick and 2 pallets of cementfrom the axles back to the very end.

 

I guess stressing tongue weight cannot be done too often. I agree that it probably is the cause of the majority of fishtailing. With heavy trailers the "armstrong" method of estimating tongue weight can result in a big error. The Sherline scales are pricey, but I guarantee you end up with bigger expenditures if you have an accident. I have a 1,000-pound grain scale, but I wonder if anyone else actually weighs their tongue.

 

Most of my towing was with a tandem-axle trailer with a GVW of 7,000 pounds, which I often towed with a full load on cross-country interstate runs. I never had any serious instability with this rig. The tandem-axle design tends to want to go in a straight line and this adds stability. This trailer had a very long tongue and that adds stability more than many would think. A long tongue gives the tow vehicle leverage on the trailer. In the other direction, a long overhang in the tow vehicle gives the trailer leverage on the tow vehicle.

My next trailer was an ancient road-roller trailer that I brought back to life. It used two 10-22.5 truck tires good for over 10,000 pounds. I had two new wheels and tires and had rebuilt the hydraulic brakes and put on a brand new surge brake system rated for 20,000 pounds - 2,000 pounds on the 2-5/16” coupler. My tow vehicle had a weight-equalizing hitch with heavy bars, but I already had three strikes against me and did not know it:

o Very short trailer tongue
o Long vehicle overhang
o Trailer weight greater than tow vehicle

Add surge brakes, with no ability to actuate separately from tow vehicle's brakes, and you have a recipe for disaster. Still, I made two cross country trips with no noticeable instability. First with a medium load. Then I hauled a Caterpillar D-2 tractor, giving me over 12,000 GCVW. I had no problem at all, including a panic-stop in LA traffic. Glad I put $$$ into having good brakes. On my 3rd trip things did not go so well . . .

 

Archie -

Darn, I'd forgotten about Lucy and her collect-the-rocks hobby! I also don't remember if Desi & Lucy's tow vehicle was a wagon or sedan.

Steve

 

Steve,

All I remember was the tow vehicle was a big convertible - I think it was a Lincoln.

(Nice to know I am not the only "dinosaur" on these forums.)

 

Archie -

Yep, it was a ragtop, but looks like a Merc:

http://www.imdb.com/gallery/mptv/118...th_key=0047191

I insist that my wife calls me "MR" dinosaur!

Steve

 

Steve - At least it was a Ford product. It looks as if I have hi-jacked my own thread, better get back to business before someone notices . . .

 

On my 3rd cross-country trip with the "new" trailer, I had a small load - a metal-cutting shaper that was deceptively small for something that weighted 5,200 pounds. I added some more stuff and the trailer weighted 8,500 pounds - much less than the previous trip. I was careful to keep my tongue weight up and even re-chained and moved the load forward to do this. It was summer, so I left at night to get through the San Joaquin Valley before the heat of the day. At around 200 miles it was midnight in a beautiful night and life was good. Those of you who drive I-5 know that there are places where it is not the best stretch of road, and I hit one of these where rectangles of concrete had been cut out and patched with asphalt. There were a series that only were on half of the lane I was driving in. I thought to myself: “This sucks.” and about that time there were a series of alternating patches - left, right, left, . . . At each thump, I noticed that my rig was starting to slowly fishtail left and right, and even after I was on smooth pavement, this VERY SLOW fishtailing increased. I could not put on my trailer brakes manually, so I tried feeding in some gas to pull the rig straight. For the record, this helped, but when I eased slowly off the gas and went through 60 mph, the resonance built up again and there was nothing I could do. I fancy that I have at least as much driving skill as the average “bear”, but there was really nothing that worked. As the oscillations increased, the short trailer tongue finally pushed me around sideways. Sideways at 60 mph! I thought: “What next?” and then the tires grabbed and over I went. I clearly remember watching the world revolving through my windshield & thinking: “Is THIS the last thing I ever see?”

After 1-1/2 turns, I skidded off the road on my roof, hanging upside-down from my seat belt. The trailer had popped off its ball, torn the safety chain off the frame, and was only a short distance away on its side. I released the seat belt and rolled out on the ground, very glad to be alive. Then all the sound (which apparently had been suspended) came rushing back. What was that familiar sound? My 390 engine was happily idling away upside down, so I reached in and shut off the ignition. It took two rollbacks four hours to get all my mess off the shoulder, but I was happy to be alive to pay the $800 bill!

 

Archie -

Sorry, I helped with the hijack too!

Your experience is one more example of what in-cab control of trailer brakes could have prevented. Glad it only cost you $$$ and not much, much worse.

Steve

 

This is why NOW that I know what I do about trailer brakes and loading I will never tow anything without a full WDH and SWAY CONTROL with a Brake Controller even a fraction over 55, will use back roads so that I don't even get CLOSE to 55, and will happily spend all day for a three hour haul just to get there with everything in one piece.

Myself included...

Things to avoid:

1) High center of gravity on the trailer.

2) Low or negative tongue weight.

3) Mechanical (surge) trailer brakes in poor condition.

4) Crosswinds (slow down!)

5) Rough roads (slow down!)

6) Downgrades (slow down!)

7) TALL Trailers.

8) (Straight out of Monty Python) THOU SHALT NOT PASS!!
-Passing a truck with an iffy load on you is likely to make the truck you are passing speed up. If you try to tuff it out, the bow-wave of air from the other truck will INSTANTLY cause fishtailing. I tried to pass a jackaxe once who was doing 40 in a sixty five zone with a bad load on. Sure enough, the next thing I knew we were going 65 verging on seventy side by side because the creep decided he wasn't going to let me by...

One guess what happened! I'd still like to find that guy and knock him out...
In front of his girlfriend, matter of fact.

*The reverse of this is also true. If someone with a funky load is PASSING YOU, or trying to - DON'T speed up to cut them off. BACK WAY OFF and get ready for evasive action. anything else may lead to disaster.

9) You may not have an LDH, but you can add a SWAY CONTROL device very inexpensively.

10) Plain old IMPATIENCE. You're going to get there, don't sweat it. If time of arrival is that big a deal, you are TOO LATE anyway. Figure that from the beginning. It's better to be late and have everything safe, than it is to not make it at all.

 

One of the reasons I hope a lot of people read (& contribute to) this thread is that I thought I understood fishtailing from a theoretical point of view. I now see what mistakes I could have avoided:

o short tongue on trailer
o long overhang on tow vehicle
o not slowing down on dubious road (thanks Greywolf)

Another mistake was not ignorance, but lazyness. As I put this trailer back on the road, I chose the surge brake system. I knew it had limitations because of the lack of manual control. I had plans (& still do) to put a manual vacuum actuator on the tongue that would apply the surge master cylinder. I still have the trailer and the necessary components (interited from my Dad who was vacuum trailer brake fan in the '50's). I am still putting off the project, but you can bet that I will not have a full load on the interstate until the trailer has a longer tongue, with the vacuum system installed.

Another thing to stress is that my instability came as a complete surprise. The road pavement was the "trigger", but I had towed this trailer over 12,000 miles with no hint of instability. Thanks also to Greywolf's list of other "triggers". I have talked to many people who had had major fishtailing incidents. It is sort of like having a heart attack: you hear about "chest tightness" but after you have it, there is a whole new meaning to those words and you find that you are now in a fraternity that you did not choose to join. One of my Dad's most respected friends was very experienced in towing and when I started telling my story, he picked it up and told me, amost word-for-word what happened.

I know there are terrible "accidents waiting to happen" out there - I have seen them go by me wondering how the driver could continue on with a constant minor fishtailing. On the other hand, I recommend the rest of us to remember that a tow rig with a hitch at the back of the tow vehicle is already in the "zone" of being unstable and avoiding anything that would "put it over the top" should always be on your mind when hitching up. Going slower is always an option - I know I would not have had my accident if I had been going 50 or even 55, but 60 was too much.

 

While speed was certainly a contributing factor, I hope those who read this will understand the other factors are equally important. A close call with my first camper on its first outing taught me the importance of tongue weight - tried to push my truck on the first downhill turn, only doing about 40. I had foolishly loaded it neutrally, thinking less weight on the rear of the truck would be a good thing. Fortunately, shifting a couple large coolers was all that was needed to remedy the situation.We go up to the races at NHIS with a group of about a dozen campers, and when someone new to towing joins the group, we often hear them complain about the handling without knowing why. ( Unfortunately, it doesn't seem to matter how much this has been discussed in front of some folks until they've experienced it). I carry lots of extra water for the long weekend, and lending them a 5 gallon jug or two to put in the front of their misloaded camper is generally all it has taken to get them pulling in control. You don't have to be unbalanced by much, for it to make a huge difference in safety. People screw this up all the time towing vehicles too - they often load the car with the engine to the rear of the trailer - creating a very dangerous situation. If the rear of your tow vehicle can't handle the weight, don't do the tow ! A weight distributing hitch can make a big difference.

 

Shifting coolers and other passive objects are a problem, but you can't beat an ACTIVE load for causing trouble. My cousin was towing a long stock trailer hitched to the bumper of a '60 F-100. He only had two heifers in the back. They started "dancing" around while he was on a down-grade and the whole rig went for a wild ride. The truck didn't go over, but the trailer got laid on its side. (Yes, they went to a goose-neck.)

 

While I've had my share of "wild" rides because of misloaded trailers, I've never had one cause an accident. We witnessed one a few years ago though, a fellow had bought a new F150, driven it to the lot where he had bought a new TT(do you see where this is going?), hooked up and headed to a CG about 100 miles away. He had made it about 40 miles when he passed us going probably 70MPH and let the trailer drop off on the shoulder when he pulled back in. When he snatched it back, it started to fishtail and the whole rig ended up rolling 2 times right in front of us. I was pulling a 1500lb popup with a BroncoII at the time and had to do some fancy driving to keep out of the accident myself.
I had a 26' 5er try to sway on me once on the interstate, swung twice, then straightened out. Really have no idea why it did it, no wind, no passing trucks, just a quick reminder to stay alert I guess. Never did it again in 25K miles pulling it.