Bigger hitch capacity or weight distributing hitch?

[Skyco]

The one problem I was hoping this would help was the way the truck/trailer combo would "pogo" on the freeway due to the ripples from the way they screed the concrete.

I think this has to do with resonance due to certain wheelbase combinations coupled with spacing between joints in the concrete. Do you find it varies a lot with speed? I have experienced this myself on certain roads. Might try different drawbar lengths to see if you can move the resonance point to a different speed.

In the 80's we were on vacation from SC to CO..got on this one concrete freeway in CO that bounced the Ford Van plus Tent Trailer terribly in a rythym. So bad that every 10 miles or so the back door of the van would unlatch partially! I would have to stop and slam it shut again. Never happened anywhere else in thousands of miles of towing!

 

[tommu56]

I think this has to do with resonance due to certain wheelbase combinations coupled with spacing between joints in the concrete. Do you find it varies a lot with speed? I have experienced this myself on certain roads. Might try different drawbar lengths to see if you can move the resonance point to a different speed.

I had the same issue in Jersey years back It would buck like a bronco every once and a while at certain speeds I would have to stop once I found the speed I just stayed over or under it (usually over)

I never measured the wheel base of the truck and truck rear axel to the trailer but they might have been the same????

tom

 

[Dmace]

The one problem I was hoping this would help was the way the truck/trailer combo would "pogo" on the freeway due to the ripples from the way they screed the concrete. I do not have this problem when traveling w/o the trailer. This, sadly is also unchanged.

Then the hitch is not setup properly, tighten up the chains a little. It's easier to hook up the chains and lock the brackets before lowering the weight of the trailer full onto the truck.

 

[Reg]

Update:

I thought it might be nice to close the loop on this, if only to say thanks for those who helped and to leave some advice for any future searchers.

I got the WD hitch. It took a while for all the parts to show up, but I got it all settled and working about a week ago or so. I haven't had time to use my tractor lately, so it took a while to get everything ready but I haven't needed it until the past week, and I've been towing it a bunch the past week or so.

Here is my opinion on this: I should have just got a higher rated receiver for the truck. It would have been simpler in many ways.

I never had any sway instabilities with this setup before (when I was running over the hitch rating w/o WD). I still don't = no change. Steering in the truck is unchanged. Basically everything I could feel is unchanged. The one problem I was hoping this would help was the way the truck/trailer combo would "pogo" on the freeway due to the ripples from the way they screed the concrete. I do not have this problem when traveling w/o the trailer. This, sadly is also unchanged. So while I am now safely within the limits of my hitch, I have the added hassle of dealing with the WD hitch whereas if I got a bigger receiver, I could just hitch and go like before. Installing a receiver would have been a simple unbolt old,/bolt in new, so that isn't anything difficult, and the initial setup of a WD hitch takes a bunch of time also as you try to get all the settings correct. I think that would have been a wash either way.

Since I will have this truck a long time, I would have been far better off getting a heavier receiver. Not that the WD hitch use will be too difficult, but I could have avoided all that extra effort forever forward.

Other folks with different situations may have different answers to this. This is mine. I'll live with the WD.

Thanks again for all who helped, and I hope this helps someone in the future.

-Dave

Yeah, well, kinda/sorta...
Pogo'ing doesn't go away COMPLETELY until you go to a gooseneck trailer and get the ball AHEAD of the rear axle center line - but that is a whole 'nother discussion.

If it is still BAD then you probably need to adjust tongue load and then the hitch bar tension (again).
It can be a reiterative process, but worth it.

The load re-distributing hitch (should have) at least reduced the probability of sway.
Even if you never experienced it you were still prone to it - there is a first time for everything, etc.
Exactly the wrong combinations of road surface, cross winds, speed, steering input, etc. can start a sway in a rig that has been driven fine for many thousands of miles with no previous symptoms of sway.
Just saying you have wider margins now - unless you use 'em up (-:

 

[Diamondpilot]

Yeah, well, kinda/sorta...
Pogo'ing doesn't go away COMPLETELY until you go to a gooseneck trailer and get the ball AHEAD of the rear axle center line - but that is a whole 'nother discussion.

(-:

This is not always the case. The worst beating I have taken was in a 1 ton pulling GN on I 65 around Louisville. My neighbor says the same stretch beats him to death every time they go to Florida pulling a 5th wheel.

Chris

 

[Ford tractor]

The one problem I was hoping this would help was the way the truck/trailer combo would "pogo" on the freeway due to the ripples from the way they screed the concrete. I do not have this problem when traveling w/o the trailer. This, sadly is also unchanged. So while I am now safely within the limits of my hitch, I have the added hassle of dealing with the WD hitch

-Dave

Dave, if the rig in your avatar is how you load, then a lot of your pogo problem is due to the way you have it loaded.

Looking at the picture (with my famous eyeball scales) it looks like you have more weight to the rear of the trailer than the front. No way is there 15% of the total load weight on the ball. Try this, with the WD bars not connected back the tractor on the trailer so the winch in up against the front lip. I'll bet money that the back of the truck sags to beat the band. That's OK, now put the WD bars on and it should bring the back end up to near level. It probably won't pogo when loaded that way. The pogo is often from too little ball weight.

happy hauling.

 

[Diamondpilot]

Dave, if the rig in your avatar is how you load, then a lot of your pogo problem is due to the way you have it loaded.

Looking at the picture (with my famous eyeball scales) it looks like you have more weight to the rear of the trailer than the front. No way is there 15% of the total load weight on the ball. Try this, with the WD bars not connected back the tractor on the trailer so the winch in up against the front lip. I'll bet money that the back of the truck sags to beat the band. That's OK, now put the WD bars on and it should bring the back end up to near level. It probably won't pogo when loaded that way. The pogo is often from too little ball weight.

happy hauling.

I think he is right.

Chris

 

[catskinner]

Looking at the trailer, the wheels are almost centered, like a balance. I would agree with hitch weight also. Best bet would be to go to a truck scale and find out. I would try to get aleast a 3" to 3 1/2" droop on your truck before locking in the wd bars if possible. You were correct on getting the wd setup, just need the weight more forward for that style trailer.

 

[hawkeye08]

We bought a tongue scale (yes I know about the bathroom scale setup) to make sure we selected a trailer (we bought used and looked at a bunch before buying) that we could tow. It is very surprising how just a few things effect tongue weight so easily... like whether you have a full tank of fresh water (we either have a full tank or an empty tank, no sloshing around for us) and where the tank is located, how much in the fridge, etc.

 

[Highbeam]

Keep trying, the porpoising is a common problem that can be somewhat fixed but I would always expect a bit of it. This is not the fault of the WD system as you point out. So now you are legal. I do believe that your trailer is very tough to load properly with the wheels so far forward.

Here's a photo of mine from this weekend. The weight is perfectly distributed. Very smooth ride. With more weight to the aft, such as when the mower is on the tractor, the combination porpoises noticably more.