Trucks & Trailers - Boat is bullying my Suburban, any suggestions.....

My boat, '83 Grady White 204 Fisherman Center Console with Suzuki DT 225. Probably around 5k loaded down, its certainly not a big boat but an old heavy battle wagon for that size boat.

We went to the lake this past weekend. We had a couple extra kids going with us to tube and swim so we pulled the boat with my wife's '06 Chevy Surburban (Z71 4wd). When I jumped on the interstate, all was good until we got between 60 and 65 mph, then the boat started whippin a little bit. What I'm tallking about is when it starts to whip back and forth. As I let off the throttle and got back to around 60mph, it would stop. It didn't do it real bad, but enough to make me slow back down to 60mph. At 60mph or less, it was as smooth as glass. I have no idea what caused it to do this. I've pulled the boat once or twice at highway speeds before with the Suburban and I don't remember it doing this. Maybe it did and I just don't recall, its been a while.

The hitch on the Suburban is a Reese 2" drop hitch in the receiver. I think the Suburban has a tow package since it came with light hookups, receiver hitch, etc.

My question is, what causes this? I believe I've read that its too much tounge weight, is that correct? The only thing I can think to do is to turn the hitch over to give it a little more lift, maybe that would help? With the stance of the Suburban and the 2" drop hitch, the Suburban and the trailer sit almost dead level. Nothing has changed with the trailer setup really, I had the bearings blow on one wheel a couple weeks ago and it was repaired by a reputable shop. The axles weren't moved or anything like that.

I typically always pull the boat with my Dodge 2500 diesel and its always pulled rock solid. I pulled it a little ways today as I was taking it back to where I store it. I got up to 70mph and I didn't really notice anything other than the road being a bit bumpy once or twice, certainly no whipping or pushing my truck around.

Any advice on how to help the Suburban out would be greatly appreciated.

Tongue weight can be a huge problem and cause issues as you described. As an owner of a Tahoe, I will tell you that I think the full size GM SUVs suck for towing as you approach 5k lbs due to their soft ride and short wheelbase. Power is fine but the instability of the platform is not confidence inspiring. Take it to a cerified scale and find out your weight distribution and adjust how you pack the boat. From there maybe airbags or a weight distributing hitch?

I have towed a 25 ft pontoon with 6 people in my suburban for over 100 mile trips on the interstate with no trouble. I don't think a short wheelbase is the issue - it is a suburban...

I'd try flipping your hitch as you suggested. There was another post on here asking if doing just that was safe. Tons of people replied they have been doing it for years, including myself. My money is on too much tongue weight.

I'll try flipping the hitch. It only does it when I hit right at 65mph on flat or a downhill grade. Less than 65mph or going uphill and its smooth as can be. I don't really ever tow with the Suburban but I'd like to be able to if I need the extra seating.

This is generally caused by tongue weight either too heavy or too light. 5K load should put about 350-500 pounds on the hitch.

Get a set of air bags for your rear end and stiff it up some will help but do what the other say first that will make a big difference.

Sounds like a tongue weight issue. You may be able to adjust your trailer by either sliding the front post (where the winch is) back a few inches or even moving the axles up a few inches. There is no problem for your tow vehicle for that size boat.

I am thinking too LITTLE tongue weight.

In additon to all that has been said, make sure the trailer tires are full and in good shape. Sometimes someone along the way installs a non-trailer tire.

I am thinking too LITTLE tongue weight.

If the trailer is swaying, your tongue weight is too light. Slide the boat forward a bit, if you can.

1. Make sure you have at least 500 lbs of tongue weight (based on your weight estimate of the boat and trailer).
2. adjust the hitch height to have the trailer level when sitting on the hitch.
3.Trailer tire pressure to the max shown on the sidewall.
4.Tow vehicle tires to the max pressure on the door frame.
Don't tow over 65 and you should be happy.

I am thinking too LITTLE tongue weight.


What ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ he said.

Another vote for the tongue weight being too light. The tongue weight also gets lighter as you increase the speed on the freeway and the wind provides some lift under the boat. Move the boat forward the problem should go away.

I am thinking too LITTLE tongue weight.

x 4 or so, on the too little tongue weight. :grin:
I believe the Suburban has one, but if it doesn't, a rear anti sway bar would also make quite a difference in preventing trailer sway.

Move the boat up a bit. Here is a nice set up if you wabt to improve the Suburban tow.

http://www.activesuspension.com/

boats needs to move forward on the trailer. good luck

Thanks guys, I'll see what I can do to get the boat moved forward a bit.

I used to own a 84' grady white cuddy cabin and towed it with a 99 suburban. Towed it fine on long trips to the keys and never spun a tire at the ramp. Must be the tongue weight.

If the trailer is swaying, your tongue weight is too light. Slide the boat forward a bit, if you can.

^^ This^^ trailer swaying at speed is generally because weight is too far back on trailer (tongue light).

Tongue weight is too light, did you have a full tank of gas in the boat?
When I towed a similar size boat with my Suburban, I could tell if the boat had a full tank verses a 1/4 of a tank.
Changing the drop on the hitch will not help, you may need to move the boat forward on the trailer a couple of inches

Swaying in generally not enough tongue weight. I saw it on a snowmobile trailer I was following (we were in the same group) and mentioned it to the guy at the next rest area. We slid the sled as far forward as possible, and the swaying went away. You need proper tongue weight and a level trailer.

1. Make sure you have at least 500 lbs of tongue weight (based on your weight estimate of the boat and trailer).

Most boat trailer owners manual specify a MAXIMUM of 10% of the actual weight. No need to overload the long tongue. With the wheels way in the back of the trailer and no flat front, boat trailers are much more stable than travel trailers or cargo trailers. Minimum specified is usually 5%.

OP -
I would find a truck scale and get the axles weighed. Then go home and measure the tongue weight with a bathroom scale (http://hildstrom.com/projects/tonguescale/index.html) or tongue weight scale (http://www.sherline.com/lm.htm). My guess is you are ~3%. If your axles just bolt on, loosen the bolts, slide them forward a foot, and measure again. If they are welded on, slide the boat forward and adjust the bunks accordingly. I'd aim for about 8%.

If your axles just bolt on, loosen the bolts, slide them forward a foot, and measure again. If they are welded on, slide the boat forward and adjust the bunks accordingly. I'd aim for about 8%.

You got the axles part backwards.

You'd want to move your axles back to increase tounge weight, sliding them forward will lower the tounge weight.

OP, Just move your winch post fwd an inch at a time if you can. A little bit can make a big diference.

We went to the lake this past weekend. We had a couple extra kids going with us to tube and swim so we pulled the boat with my wife's '06 Chevy Surburban (Z71 4wd). I've pulled the boat once or twice at highway speeds before with the Suburban and I don't remember it doing this. Maybe it did and I just don't recall, its been a while.

I typically always pull the boat with my Dodge 2500 diesel and its always pulled rock solid. I pulled it a little ways today as I was taking it back to where I store it. I got up to 70mph and I didn't really notice anything other than the road being a bit bumpy once or twice, certainly no whipping or pushing my truck around.

Any advice on how to help the Suburban out would be greatly appreciated.

Your weekend trip with extra kids also likely included extra gear in the boat.
More gear than you normally haul.
On a regular basis I bet your tongue weight is right at the right amount.
I bet you did not have any of that stuff in the boat when you hauled it back to the storage yard with the Dodge.
Until you load that extra gear into the back of the boat, all is well.

I bet you do not have to change anything other than how you load stuff into the boat.
So as not to "teeter-tawter" the weight distribution aft.

Is it a single axle or twin axle trailer? Twin axle trailers seem to be more stable when you get moving at higher speeds/

You got the axles part backwards.

You'd want to move your axles back to increase tounge weight, sliding them forward will lower the tounge weight.

Dough! dreamin-on is absolutely correct! Axle needs to move BACK or boat forward.

I once had a boat i towed with a van, no problem. then bought a car and it swayed all over the place, what we figured out was the van blocked the wind from hitting the boat, but the car allowed the wind to get under the boat and it started to float. adding tounge was the fix.