Here's a head scratcher...

[billyman]

First, I hope everyone had a safe and fun-filled 4th of July.

I brought my boat home w/ out incident last Saturday. I go to take it out Tuesday night and as soon as I pull out of my drive way and head down the road I feel a noticable "jiggle" between 20-25mph. I say jiggle b/c it doesn't feel like a vibration. It literally feels like someone is standing in the boat and rocking it side to side, but only between 20-25mph. What's weirder is when I get up to speed and coast, the "jiggle" doesn't seem as bad as when I'm accelerating through the 20-25mph band.

I have checked the hubs and tires, had my g/f drive by me over and over looking and listening for any rubbing, grinding, tire wobble; basically anything abnormal and I see/hear nothing.

So... That being said, has anyone experienced this before? Let the troubleshooting suggestions begin.

 

[Davem3]

Re: Here's a head scratcher...

bad tire, maybe???
also, check the springs and axle???

worse case, it the weight balanced ?????

 

[ricohman]

Re: Here's a head scratcher...

How new are your tires? I've seen many tires bulge and go out of round as they age. And it happens suddenly. You will feel the vibes at a certain speed, not so much so at highway speeds unless you have a really big separation.

 

[billyman]

Re: Here's a head scratcher...

Thank you both for quick reply.

Davem3, I did check the springs/axle; they are solid and the boat is balanced on the trailer.

ricohman, I just bought the boat/trailer in April, but I believe the tires are the original tires that came on the trailer in 2004. They look good; no dry rot, decent tread however I have noticed some cracking around the base of the valve stems, but not on the tires.

I think you both may be right in citing the tires as the problem. While I didn't see any huge (noticible) bulges, I think it might be time to get new tires.

Thanks for the info.

 

[jeffnick]

Re: Here's a head scratcher...

I'd suspect a tire problem. Jack up one tire at a time and feel the tread as you rotate the tire. Also look for a spot with irregular wear. Could be on your car/truck as well.

 

[Philster]

Re: Here's a head scratcher...

The boat and trailer have a harmonic vibration because of how they are mated.

Is the boat sitting the way it always has on the front roller and the bunks? Is the front cinched down tightly as well as the transom straps.

I swear, most of these 'it vibrates around 30 MPH' type complaints are about the boat not sitting right on the trailer (should be damn snug/tight).

Seems fine to the ramp, then going home it isn't = something is different about how it's loaded. Maybe the straps loosened a bit when sitting. Maybe your driveway is on a hill and the boat moved. Maybe your driveway has a bump that jostles the setup.

Before you think the trailer developed a problem sitting, consider it is more likely the boat and how it sits and is attached to the trailer might not be quite like it was when this vibration didn't happen.

Also: dirt in trailer fender can collect and get heavy and contribute to the vibration.