I would LOVE to see a video of what you are describing.

 

I have no clue how to make a video to post online, all I've got is a flip phone and an old super 8 movie camera. I'm not even sure what we're seeing would show up in a video other than things on the dash jumping up and down or soda splashing around in the bottle.

When the truck accelerates, weight transfers to the rear, the front end raises up, it does this normally without the trailer, when the trailer is on the truck, it seems to bounce in the front end but only the tires seam to be taking the effect.
With this in mind, I inflated the tires to to the full 85 psi on the sidewall, front only at first, (they were at 55 psi as recommended on the door sticker). The rear tires were at 75 psi.
Raising the front tire pressure to the max reduced the bucking by nearly 3/4 or better, it was still bad but not so bad you couldn't speak or tune the radio.
I increased the rear tires to 85 psi as well, and saw no real change.
Over inflating the front tires to 95 psi reduced the bucking even more.
(I didn't leave the tires over inflated for safetly reasons but it shows that tire pressure helps).

The suspension on this truck is stiff, it always has been, but more so in the rear than the front. Its a solid front axle truck with leaf springs. It takes more than a thousand pounds of tongue weight to put the rear end down on the springs, but the front rides a bit softer. When empty, the rear of the truck rides nearly as if its on solid suspension judging by the way it rides. The front end is a bit more forgiving. I can stand on the drawbar in the hitch and bounce up and down and the truck doesn't move, I weigh nearly 350 lbs. The 1995 F350 isn't like this, its suspension is softer when unloaded, but it firms up once you get to the helper springs. However, the F350 springs aren't nearly as heavy duty looking as those on the 03 F250, the 03 main leaf is thicker the full length, where as the F350's springs are thin and more staged.
The F350 front end is sprung a lot stiffer though, which explains how brutal it is over bumps.
Of course, I'm not sure how much this all means here since again, the trailer doesn't buck on any other truck, including both of my F150's and my Ranger.

What I'm starting to think is happening is that any fore and aft motion occuring on the trailer due to weight transfer, is causing the truck to transfer that effect to the front. The rear suspension isn't dropping when the trailer applies down force, so the front end raises up or unloads.
Again, with this in mind, I dropped the rear tires to 45 psi and took a test drive, this nearly eliminates the bucking at higher speeds, but not at lower speeds. It settles down over 50 mph. The problem is I can't run the rear tires that soft and the front tires at max inflation. I tried bumping up the rear pressure to 55 psi but got the bucking back. With the tire pressure lowered, I could hear the drone of the tire tread changing as the bucking started and stopped and adjusting my mirrors down, I could see the rear tires bulging, in and out as the bucking occurred. With the tires that soft, the back end of the truck felt unstable as well, sort of squishy side to side, which is why I didn't leave it that way.

If it didn't do the same thing on a similar new truck, I'd say it was my truck, but having tried at brand new F250 4x4 like mine and gotten the same thing I don't really know what to think.

 

When you say the front of the truck lifts on take off like drag racers want for better traction out back I wonder if you can easily change Instant Center (IC): so the front will not lift much?
Dave ----

 

Put a ton in the bed of the truck as far forward as possible. See if that smooths things out.

 

Easy solution
A. Sell problem trailer
B. Purchase different trailer

 

The problem is that the truck has a tool box at the front of the bed, (full of tools), but anything behind that is over or behind the rear axle. (shortbed).

I've probably got about 450 pounds in the tool box as it is, and another couple hundred in the back of the cab.

I'm won't be able to try anything for the rest of the week, my buddy borrowed the trailer to go to Missouri to pick up a tractor he bought online.
He's pulling it with an older Explorer with a 5.0L motor.

Its fine behind his Explorer, as it is with just about anything but my F250.

I won't likely sell it because it tows fine behind all the other trucks.
Its the F250 that seems to have issues with it, but the F250 tows everything else just fine. With only 16k on the F250, its not likely going anywhere anytime soon unless I find someone who wants to swap me a long bed supercab diesel with the same low miles. At the current rate that I put miles on it, it'll be an antique long before it hits 50,000 miles.

 

I got my trailer back a few days ago, it made the 1700 mile round trip behind my buddies truck with no issues at all.
The weather was clear and not too cold yesterday so I figured I'd try a few things to see if I could solve the bucking issue behind the F250.
First off I took a solid bar of 2" steel and made up a suitable drawbar, I attached a 1" plate to the bottom and proceeded to make up the shortest possible drawbar I could.
I hitched up the trailer and gave it a try, to my surprise it was a lot better, with no bucking until around 35 mph. I then tried moving the ramps from the vertical position to slightly folded forward by drilling a new hole in the support bars. Again, I took it on the road, this time I only got the bucking between 30 and 42 mph.
I went back and figured I'd load the trailer and try again. I dropped the ramps and pulled an F150 onto the trailer. While I was stepping out of the F150 on the trailer I heard and felt a loud snap or clunk. My first thought was that that the trailer springs were bound or stuck from backing around the corner into the drive, but I soon noticed that the hitch didn't look right. Closer inspection showed that the trailer hitch had failed. The 2" ID tube that actually holds the drawbar had broken away on the left side and was hanging down about an inch.

I jacked up the trailer and unbolted the factory hitch. The weld on the left side was intact but there was no penetration of the weld into the cross tube.
I proceeded to grind all the welds off the hitch and I rewelded all of the joints, painted it and put it back on the truck.
The bucking is gone, it rides perfect now.
Now the question in my mind is did the hitch fail due to the bucking and the new drawbar or ramp position change was just a coincidence or was it the issue the whole time.
Worse yet, I made several 300 mile trips with the trailer bucking on that hitch, each trip was without brakes. I suppose if the brakes were working, I'd have ripped the hitch apart and lost the trailer since the safety chain loops are welded to the bottom of the receiver tube which would have no doubt torn free. Only about an inch of weld was holding solid on the right side, the rest of the welds had no penetration at all.
I've also towed my other trailers more than 3,000 miles over the past 6 months, but not on the freeway, just locally around town with light loads. If the hitch didn't drop while I was standing on the trailer I'd likely not have noticed it till it ripped completely off, most likely on the road. I was only minutes from taking a road test with the F150 on the trailer when it broke in the driveway.

 

Good to hear you found the truck hitch before you got it on the road.


As for the truck hitch as you found and wonder how many are close to failing, was bad from the factory and may or may not have showed up years from now but showed up sooner than later.


Also good to hear you fixed the trailer to tow right when pulled with the truck.
Another test would be to see if you can "road test" that other truck again to pull the trailer for a test to see if it is fixed.
Dave ----

 

I would put the ramps back to the more vertical original position and use the same original drawbar that was used when the bucking was at it's worse and see how it tows. With everything else returned to worse case scenario status if the bucking is gone, then it would be safe to assume that it was the broken hitch causing the problem. Still curious about the new truck bucking the same way though................

 

The fact that it bucked behind a new truck also has me puzzled. I did return the ramps to the original position, but haven't swapped the hitch back yet.
I did take a few drives with the F150 on the trailer and there's no bucking.
Remember though, I had tried several hitches before that had no effect, so I doubt changing the hitch will make much difference. I think the last change of the hitch and ramp position just lessened the leverage the trailer had on the hitch since the drawbar is much shorter. I think the issue was the longer drawbar putting more leverage on the hitch.
What amazed me more is that it didn't break on either of the 300 mile trips I took with it bucking. The last trip had a 6900 lb tractor on the trailer.

Also, the load eq hitch that was originally on the F250 is currently on my 95 F350 with no issues behind that truck, so I doubt the hitch was at fault.

What also gets me is that I never saw any movement in the hitch or trailer while it bucked, as well as how a bad weld could create such a violent jerk or buck in the cab without just tearing loose.
In the end, I'm just glad the issue is solved.

 

If you're running 100 psi on an empty trailer, that is most likely the problem.

 

Trailer tire has a bulge on it?

I've had it happen more than once. Jack it up and spin them one by one
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