The mechanics of fishtailing

[lukem]

To answer your earlier question, sway increases during downhill breaking because the nose of your truck pitches down, the rear pitches up and makes the tongue weight even less. If it really starts swaying hit the TBC and apply breaks manually being careful not to lock them up or accelerate out of the sway.

I like the idea of a 2x12 halfway around the front of the trailer.

 

[wkpoor]

The amount of tongue weight needed to stabil a load will vary with the distance from the hitch point to the center of the axles. A dump trailer being short and some may have a 45/55 split on the axle placement makes for a lot more hitch weight than say a 24' trailer with 60/40 split and a longer tongue on the trailer. My deckover 14K 24' deck is 30' tip to tail and is practically impossible to load where it will fishtail. My dumptrailer even though its only 12' with a short tongue is pretty stable also but the axles are clear at the back end.

 

[SolarAndWood]

I've wondered about the axle location. Maybe I'll stop buy a few trailer places with a tape measure and see where it falls in the mix. While the trailer company is still in business, they don't make my configuration any more.

 

[JeffRey30747]

Gotcha, so kick up the gain so the trailer brakes are slowing the train down instead of the truck? Alternatively, stay off the Interstate through those sections with heavy loads so you don't have as much momentum at the top of a long descent. Seems like the Interstates are graded with much longer runs like that than the 2 lane roads where you can mange your momentum a little better.

Or you can use just the brake controller to apply the trailer brakes on their own. This will allow the trailer's mass to be a drag on the vehicle instead of pushing you.

 

[SolarAndWood]

On yesterdays load, I stacked the front of the trailer tight and then loose tossed the back half. Didn't notice that it really sagged the truck much but it looks like it did a little comparing the pics of the rear wheel well. Took it up to 75 and she behaved herself. Looks like I am going to have to put some side boards on it and really pack the front to make sure I get enough tongue weight.

 

[Bigg_Redd]

This trailer is usually pretty docile but was all over the place last night and I'm not sure why. On the flat it would start about 55 and on a decent downgrade it was out of hand at 50. I think the weight was pretty equally distributed, trailer pretty level, etc. Any idea what am I missing other than a Duramax and a gooseneck?

Yes. Tongue weight. You need more of it. Front load the trailer a little more.

If your trailer is loaded evenly and you're fishtailing it means the axles on the trailer are too far forward.

 

[mywaynow]

What about the tires? All are the same? Are they all filled to the same psi? If all is equal, than maybe running the fronts lighter would shift the wieght to the tongue?

 

[SolarAndWood]

4 matched with maybe a few hundred miles on them. Does raising the ball put more weight on it? It is a little low if anything.

 

[Bigg_Redd]

4 matched with maybe a few hundred miles on them. Does raising the ball put more weight on it? It is a little low if anything.

No. You want the tongue level. Raising the ball raises the tongue which actually takes weight off the tongue.

 

[lukem]

The road can have a lot to do with it too. I hauled a tractor over the weekend. The first couple miles sucked and I thought it was going to be a LONG ride home, but once I got off that road it was smooth sailing. If I wasn't stopping or starting, the 6k behind me wasn't that noticable.

 

[MasterMech]

Solar,

Little low on the ball is just fine and should help stabilize the trailer actually. Little low is preferrable to a little high. In your pics you can see a big difference in how much the trailer tires are squatting.

 

[Jags]

In your pics you can see a big difference in how much the trailer tires are squatting.

Yep, I noticed that too. Did you air them up or was the load a bit lighter?

 

[greg13]

Once again and I see it all the time, NOT ENOUGH TOW VEHICLE!! Trailer is not loaded correctly, Not enough tongue weight.

 

[SolarAndWood]

NOT ENOUGH TOW VEHICLE!!

NOT SURE WHAT YOU ARE YELLING ABOUT IT IS A 3/4 TON TRUCK TOWING A 6X12 TRAILER!!

 

[SolarAndWood]

In your pics you can see a big difference in how much the trailer tires are squatting.

Yep, I noticed that too. Did you air them up or was the load a bit lighter?

Front half is about the same as the first trip. I loose tossed the back half to the height of the box. So, probably a ton less in the back half of the trailer on the second trip.

 

[lukem]

NOT ENOUGH TOW VEHICLE!!

NOT SURE WHAT YOU ARE YELLING ABOUT IT IS A 3/4 TON TRUCK TOWING A 6X12 TRAILER!!

You'd better step it up to a F550 to tow that trailer LOL!

 

[SolarAndWood]

lol, I'd need a cdl to pull that trailer with a F550 in NY.

 

[leaddog]

Watching trailer balance is REALLY important. If the trailer doesn't feel right STOP and fix it. I WATCHED a 30ft travel trailer being pulled by a 1/2 ton make a complete 180 at 60 MPH coming down a slight grade on a state highway. Ended up on the shoulder going the oposite direction and never left the road way. One bar came off the hitch, Truck frame was bent, total mess inside the trailer, and the driver, wife and kids I'm sure had to change underware. He said it started to sway and he touched the brakes--------------. They had filled the water tank in back, put there gear in back on the bed etc so they had a slight heavy back. They had equalizer hitch, sway bar and that wasn't enough. Oh, 1/2 ton was two small for a 30ft also. The next year had a 3/4 ford pulling a 22ft try the same thing same place only trailer fliped, truck went down the embankment, but was able to drive out and noone was hurt, Trailer was in a million pieces.
I had a load back heavy once with wood and just drove it home at 35mph. STUPID. after seeing what can happen never again. It only takes a couple minutes to throw some fron the back to the front.
leaddog

 

[bioman]

It's all about trailer weight distribution, simple as it is , Front is good, back is bad. if you put enough weight on the back it will lift the rear wheels of the tow vehicle & you will go nowhere, No matter what it is , load it right or don't haul it. we all share the road so be safe.

 

[savageactor7]

Hi SolarAndWood

I agree with the load balance advice. iirc over the over the road tow trailers are supposed to be loaded with 60% of the weight over and forward of the trailer tires.

 

[nate379]

I made the mistake this summer of loading too tongue heavy. I had bought 4 cords of firewood from a guy on Craig's List. I took my Ram 2500 diesel truck and my 10k 18ft car trailer. I had planned on loading the truck and trailer and making one trip.

Started loading the trailer at the front, corded the wood about 3-3.5ft high across the deck and then strapped it down (I don't have side boards). WELL... by the time I got to over the axles, I was out of straps. I had around 2 cords of wood on the trailer by then, somewhere around 3.5-4tons of wood. The way I had the truck parked, it didn't look like it was sagging too much, SO... I decided to load the bed of the truck as well.

I didn't realize how heavy I was loaded till I pulled forward onto a more level area.
I have airbags over the rear axle, and usually 60-70psi is more than enough to level the truck. I brought them up to 100psi and it was "ok". I didn't want to blow apart the bags so I didn't go anymore.
To compare I have hauled a 275gal tank of fuel in the bed (~2300lbs) and bags only needed around 50psi.

The trip home was maybe 15 miles, but it ending up being a 45-50mph trip. It felt like I was driving a boat, where you kind of turn and eventually it goes that way. Had I had a lighter duty trailer or truck I probably would have damaged something.

 

[Dune]

Solar, if it is possible , move the axels back. That is the safest way.

 

[SolarAndWood]

Solar, if it is possible , move the axels back. That is the safest way.

I thought about that but the design makes it nearly impossible. The big frame you see in front of the wheels ends where the rear of the fender connects and that is where the hinges are. I like the trailer because my tractor just fits in it. So, I think it is either use it as is and heavily front load it when I am loading material or get rid of it. The county has now decided that anything with 2 axles is commercial for the transfer station and the compost/mulch site. So, right now I am leaning towards getting rid of it and just using the little dump.

 

[MasterMech]

Wonder if a moving axle carrier like what's found on semi trailers would catch on for smaller trailers like Solar's dump? Those guys manipulate axle position all the time to allow maximum payload and keep the axle loading legal on the scales.

 

[SolarAndWood]

I suppose I could also just cut the last 30" of the box off behind the hinges. It would dump better and loading the front of a 12' trailer by hand is less than ideal anyway.