How to control fore and aft rocking

MuskyHunter · 07-15-2007, 07:08 PM

Man, had a rough trip this weekend towing my boat. My stomach feels like it has been put into a paint can shaker. I was (and still am) popping Rolaids like candy.

The situation is that there are a few stretches of road has a slight rise near what would be the expansion joints. (For the guys in Wisconsin, the stretch of 151 from Sun Prairie to Beaver Dam and hwy 41 from Nenah to Appleton).

Pot holes are not the issue. The best way I can describe the road is like you are rolling across waves. I think heat causes the concrete roads to buckle up a bit instead of staying flat. What I got was a nose to tail rocking at highway speeds for hours and regardless of what speed I chose, I couldn't get a smooth ride.

It seems like that when the rear wheels move upwards because of the rise in the road, when it comes down the extra weight from the trailer pushes down causing the front to rise. When the front comes down, the back rises again.

The boat and trailer is about 2400 lbs, tongue weight is not significant. Truck has 16,000 miles. I ran into the same problem with my old GMC. I have played around with tire pressures going higher and lower with no real noticable changes.

My trailer is not perfectly level as it is about 13.5" off the ground at the receiver and about 15" at the back. I have a 4" drop receiver. What I am wondering is will leveling this out help in this situation? I can go with a 2" drop making the front slightly higher than the back.

Also, is this a situation where airbags can help dampen the ride a bit?

Thanks in advance.

**Kronos1965** · 07-15-2007, 08:43 PM

1. Anti sway bars for your truck.
2. Helper springs. Airbags will level the load for sure but since they don't adjust "on the fly", you will still get some pitch.
3. Consider upgrading your shocks.
4. Get a load-leveling hitch set up...

Treebasher · 07-15-2007, 08:47 PM

Sounds like the boat could be balanced on the trailer better. More weight on the trailer tires/suspension and less on the trailer tongue could have reduced that bouncing on the multiple trucks you've used. It's amazing what moving a boat 6 inches back(moving the winch post, if possible) on a trailer does for the vehicle ride. Obviously, too much is not a good thing either.

MuskyHunter · 07-16-2007, 03:03 PM

Quote:

Originally Posted by Treebasher

Sounds like the boat could be balanced on the trailer better. More weight on the trailer tires/suspension and less on the trailer tongue could have reduced that bouncing on the multiple trucks you've used. It's amazing what moving a boat 6 inches back(moving the winch post, if possible) on a trailer does for the vehicle ride. Obviously, too much is not a good thing either.

The trailer is surprisingly good over all. I do not have the ability to move the boat back any further on the trailer, which then means moving the axle forward. Too bad as the trailer tracks nicely even in windy conditions. My buddies truck does this a bit as well, but is less noticable with his longer wheelbase and lighter boat.

Looking at the easiest solution first, and the common denominator being the same ball mount/4" drop, will leveling out the trailer help in this kind of circumstance with less of a drop?

MuskyHunter · 07-16-2007, 03:08 PM

Quote:

Originally Posted by Kronos1965

1. Anti sway bars for your truck.
2. Helper springs. Airbags will level the load for sure but since they don't adjust "on the fly", you will still get some pitch.
3. Consider upgrading your shocks.
4. Get a load-leveling hitch set up...

Thanks. Swaybars will help in the cornering, but I don't quite see how they will help in this situation. Have you had luck with this addition? My eyes are on the option of adding on airbags with an onboard compressor and would be great. With that or helper springs, I wonder if making the back more stiff would only aggravate the problem? A shock upgrade will be a definite but will hold off until these wear out.

Treebasher · 07-16-2007, 07:01 PM

Quote:

Originally Posted by MuskyHunter

The trailer is surprisingly good over all. I do not have the ability to move the boat back any further on the trailer, which then means moving the axle forward. Too bad as the trailer tracks nicely even in windy conditions. My buddies truck does this a bit as well, but is less noticable with his longer wheelbase and lighter boat.

Looking at the easiest solution first, and the common denominator being the same ball mount/4" drop, will leveling out the trailer help in this kind of circumstance with less of a drop?

I wouldn't think you'd see much improvement by just leveling the trailer with a less drop ball mount. The weight will still be on the tongue. A load leveling hitch might be a pretty good option because of the way they spread the hitch weight on the truck and trailer. The hitch weight should be 10-15% of the trailer load weight. I like to go more toward the 10% ratio. If you're over that maybe a load balance hitch setup is and option.

Smoke05 · 07-16-2007, 08:24 PM

Hate to say this, but it sounds like your problem is your boat and trailer set up, not your truck. You mention it has done the same thing behind 2 different trucks you owned and is a little better behind a friends longer wheelbase truck. That is a trend. If your boat weighs 2400lbs and your tongue weight is 10-15% your Titan should not even notice it back there anymore than 300lbs of cargo. Wheelbase may be an issue, but I don't really think so in your case as I tow a similiar weight boat and also a 29ft travel trailer and to get what you describe only occurs on a REALLY wavey road with the travel trailer. How far does your hitch bar extend from your receiver? It should be as close as possible to the bumper, but allow clearance as to not bind. I would weigh your boat and find your tongue weight. You may be suprised. Weight distribution would not do you any good as you do not have enough tongue weight for it to work if all weights you mention are accurrate. My brother owned a 19ft travel trailer that did what you describe now that I think of it. The trailer was rear weight biased and he could not get enough weight to the tongue to use weight distribution.

Derwud · 07-17-2007, 12:22 PM

First it's a wheel base thing, both of the truck and trailer.. What can you do to solve it. Get the nose of the boat down, better shocks, air bags - maybe.

As for weight dist. hitch, the only one I know of that will work with boat trailers is the Equal-I-Zer hitch. But I don't think it will solve your problem.

Derwud · 07-17-2007, 12:23 PM

Oh, call the state and complain about the road. It needs to be milled flat again...

FLA-Titan · 07-18-2007, 10:04 AM

Seems the tongue weight needs to be adjusted. Most likely you need to add more weight to the tongue. This occurred with my boat and i had to move it forward. My boat weighs in around 3500 pounds plus trailer. i adjusted (moved boat forward) the tongue weight to around 350 pounds. Easy to measure with a heavy duty scale and wooden block. No more bouncing or tugging on the rear.

jguns2002 · 07-18-2007, 11:23 AM

A pic of your truck w/the boat hooked up may help us. Seeing the whole thing together might give one of us an "Ahah" idea. I would try to get one of the truck and trailer in one pic & one of just the boat and trailer from the tongue back.

ptvolly · 07-18-2007, 06:10 PM

Pretty much everybody is correct here!!!
Cheap and easy?....Level it out more. Even if the tongue weight doesn't change it does affect the towing mannerisms.
I haven't used air bags, but I'm sure they would help.
Your problem is typical of not enough tongue weight, but if you can't change the position of the boat I'd start with leveling it all out.

MuskyHunter · 07-18-2007, 06:24 PM

Quote:

Originally Posted by jguns2002

A pic of your truck w/the boat hooked up may help us. Seeing the whole thing together might give one of us an "Ahah" idea. I would try to get one of the truck and trailer in one pic & one of just the boat and trailer from the tongue back.

Thanks for all the advise guys. I'll get some pictures this weekend as I will be out on the water again.

**loufish** · 07-18-2007, 09:20 PM

Quote:

Pretty much everybody is correct here!!!

Uh..not quite...
Sway bars for truck? Nope - Not for straight line
Air bags for such small tongue weight...Nope - More spring will just kill the kidneys

Need to add tongue weight and get better shocks, maybe add some weight in the bed. For some stretches of hiway you can get a harmonic effect that is as you already know built into the road, and just a bugger to deal with...

jguns2002 · 07-19-2007, 04:58 AM

Quote:

Originally Posted by MuskyHunter

I do not have the ability to move the boat back any further on the trailer, which then means moving the axle forward.

In order to increase tongue weight, you'll need to move the boat FORWARD on the trailer!!!