10% TW to 13% TW...did not seem to make any difference

Dan, the StableLoads are a product sold by Torklift. They aren't that expensive. I think I paid around 125 for the kit and another 100 for installation. They are basically steel fillers that go between the leaf springs and the overload spring. They disengage fairly easily to soften the ride when there is no load. That's why I'm not sure how they would work with airbags, but they do have a pretty good web site. If you decide to go that route, I strongly suggest you pay someone with a lift and a bit sharpener to do the in stall. I tried the DIY route and gave up quickly. The young man that drilled the holes for mine flat earned his $20.00 tip. Good luck.

The Hensley is indifferent to tongue weight in terms of sway control, but I've found towing on the way home with fresh water tank empty (ahead of the axles) and the holding tanks almost full (behind the axles) I get more porpoising than I do on the outbound with full fresh and empty holding tanks.

I agree with JBarca, sometimes it's just the road. Bilsteins will probably help some, but don't expect a magic cure to this one...these problems are unique to the rig/road combo. You many not have an issue on that stretch of I-90 and JBarca may not have an issue n that stretch of I-10, as was stated, sometimes all you can do is slow down.

My Dad used to commute to JFK in a VW Beetle, and on very gusty days he would say, "Sometimes all you can do is put on your blinker."

On a LWB HD truck there is nothing wrong with not returning all the weight to the front axle, in fact everything I have seen shows the OP as correct with about 50% restoration. Good luck trying to get 100% back, you will break things on a heavy TT.

It sounds like a road issue, but your shocks are probably worn out.

I would also hit the scales and check your axle weights and set tire pressure based on actual weight and not door placard. The door placard is based on FAWR/RAWR weights, not actual loading.

10% seems very low for a TH, even 13% seems low for a TH unless the garage is FULL. Do you weight the TW only each trip? Or the TAW too?

Have you tried bumping it to 15-16%. More TW will put more weight on the TV and might stabilize things out.

Also, does Hensly make an extended shank? It may be the position of the TV axles to TH axles and increasing it by 6" might do wonders. I know my TT tows much better on rough roads with the 6" longer hitch.

Lastly, what condition are the trailer tires in? Proper pressure?

Thnaks john for the thoughtful and informative post.

We are heading out of New Orleans this morning (to Florida and then to Maryland)...soewhere in that trip I suspect we will get the opportunity to test the theory and slow down a bit to see how it goes.

I will report back in a few days.

Thanks again to all for thier help...

cruz-in wrote:


1) with the hensely, sway and movement from passing trucks does not occur. In this regard the TT TY tows just like our previous 5th wheel.
2) Issue is just being bounced around in the truck. The pavement cracks, bridge joints, rough concrete roadway, etc. really beat us up. Mostly a very rough ride with some porpoising thrwon in.
3) Not looking for a "cadaliac" type ride, however our rigs poor behavior in these circumstances seemed extreme.
4) Speaking of the rig. It is a 36 foot toyhauler. Loaded weiht is a bit less than 12K pounds.
5) Rig drives like a dream on asphalt pavement. Smooth, no push/pull from passing trucks, etc...

Thanks again for all the advice

It "sounds" like you found the natural frequency so to speak of your truck and camper setup. And from what you and others have said, see if this fits as my F350 will set itself off as well on this one patch or road, approx 3 miles long.

In NYS heading east on I90 into Buffalo, you exit the Lakawanna toll booth, exit 55 I think, and that older set of concrete road sets my truck off into a bucking bronco. It is totally repeatable in either direction, east or west. We travel this road at least once a year. After about 3 years of this I figured it out. If I slow down to exactly 48 mph the whole rig just smooths out. If I hit 55 or higher it can get really bad. It is constant non stop front to back oscillation. I can drive other concrete road and no problem but that spot will light my rig off every time.

I have a buddy in western NY with his 2500HD Durmax and he has the Hensley too, it lights his truck off too.

Last year I changed out the orignal Rancho's and put the Blisten 4600 series and had high hopes they might help on that stretch or road. They did help the truck, especially since the Rancho's were going, I could compress them but they would not self extend. But they did not change the 48mph.... That road stretch length of concrete, the unevenness of slab to slab, my truck WB, the camper ball to axles and the WD, all add up against each other above 48mph.

I have 16% TW (1,600#) and I set the WD to be ~ 120# lighter on the front end then unhitched. I have rear helper springs and they just kiss the upper frame bracket and that helps act like a left to right roll bar for stability. I have no issues anywhere else.

If this is what you are up agasint, I'm not seeing how air bags are going to get you out of it, and odds are high, the shocks will not either. TW changes, I'm not seeing it shift this. A different camper, maybe.

Try slowing to the point it settles out. I realize that might be in that 48 to 45mph area and can drive you nuts driving a long time that way. But you will at least know.

Going much above 45mph is a critical speed point where it can set off an unstable rig into sway if the conditions are right. Neither you or I have the sway issues, but your rigs natural frequency, I'm not sure how you can practically shift that.

Hope this helps

John

"Also added stable loads to the springs"

Thanks for the info cmpigloo....could you eloborate on what "stable loads: are?

Thanks
Dan

I see you set your tire PSI by the door sticker.
Have you ever weighed it hooked up and seen the
actual weight?

Knowing your weight then you can adjust the PSI per tire manufacturer.
It may be too high.

Also I-10 can be brutal. Speed makes a difference there too.

Most of your problem is the expansion joints where the slab has sunk a bit. Think that's bad try I-55
I had the same problem. My 2012 Ram has leaf springs, so not sure about the airbags. I added a set of Bilsteins. Definafe improvement. Also added stable loads to the springs. Huge improvement. You might also try letting some pressure out of the rear tires. Not a lot, but some. Slowing down is the quickest easiest solution. After the shocks and spring helper, roads I used to run @ 45 I can usually run @ 60. Still some porposing but not enough to give you a headache.

Thanks all....

1) hoping it is I-10
2) Tried increaseing the WDH so front height was right back where it is unloaded...did not help
3) Tires are Goodyear Commercial T/As and relatively new.
4) Truck is 5 years ole and has 50K+ miles on it....no harm in upgrading the shocks...got a set of 4 Bilsteins for $250, delivered...so will at least give that a try...
5) Hoping most of it is I-10....

Thanks tons...and keep the thoughts coming...

cruz-in wrote:
Hi Team,

I appreciate you all's time and sorry for not being more specific.

1) with the hensely, sway and movement from passing trucks does not occur. In this regard the TT TY tows just like our previous 5th wheel.
2) Issue is just being bounced around in the truck. The pavement cracks, bridge joints, rough concrete roadway, etc. really beat us up. Mostly a very rough ride with some porpoising thrwon in.
3) Not looking for a "cadaliac" type ride, however our rigs poor behavior in these circumstances seemed extreme.
4) Speaking of the rig. It is a 36 foot toyhauler. Loaded weiht is a bit less than 12K pounds.
5) Rig drives like a dream on asphalt pavement. Smooth, no push/pull from passing trucks, etc...

Thanks again for all the advice

On my 5er TH I added centerpoint air suspension with shocks and a air pin box.