Trailer vibration problem

[Sailor Chlud]

Hello, fellow DS sailors! New DS1 owner here with a puzzling trailer problem. I picked up a well-preserved 1969 or 1970 boat this weekend from an owner in rural PA that rides a Tee Nee trailer rated for 1250 lbs. The PO only trailered it on short local roads at speeds under 40 mph. He had installed two new tires on the trailer and greased the bearings. On my ride home, the trailer developed a bad shimmy at speeds over 55 mph - so much so that I drove about 50mph all the way home. The trailer has bunks that I consider too short for the boat, so I'll be beefing them up, but has keel rollers too. The boat was well-strapped, and so was the mast. By the way, the tow vehichle, 2002 Chevy Suburban, is in excellent condition and tows heavier trailers smoothly, as well as drove perfectly without the trailer attached.
Can anyone kindly suggest what I might need to check out to stop the vibration? Thanks for the help!

[jdubes]

Here's what i would look at in this order.

1. Bent/warped rim
2. The rim wasn't installed onto the hub correctly. See if the lugs are tight
3. One of the tires has an egg/bad spot on it. Jack it up and spin the tire.
4. When he greased the bearings he didn't tighten the hub enough leaving some play. Jack it up and see if you can wiggle the tire.
5. Bearings are worn. Jack it up and see if you can wiggle the tire.

[Alan]

Possibilities:

Tire tread separated internally (This can be caused by a severe tire impact, with a pothole, for example, and it makes a noisy vibration. There may not be any visible damage to the tire.)

Flat spot on tire

Bent wheel

Badly out-of-balance wheel and tire

Wheel lug nuts very loose, so wheel is wobbling on studs

Bearing failure about to happen (greasing may not have been enough)

I've towed a DSII through the long 75-mph stretches in Nevada and Idaho, on a Highlander trailer with 12-inch wheels, with no problems. The tow vehicle was a full-sized Toyota SUV, so our situations are similar.

[Alan]

Oh yeah, and what jdubes said about jacking it up and spinning the tire.

[algonquin]

Lots of good suggestions already. I would add to check the spring mounts and make sure that the axle hasn't shifted. Take a couple measures from the axle to a point forward on the trailer. Measure from each side to the same point and make sure they are the same number + or - an 1/8th inch. If they are out of tolerance you may need to loosen a spring mount and move the axle accordingly. Brad

[algonquin]

One more thought on the trailer. Check to make sure the axle isn't bent. Also have someone follow you while towing from slow to highway speed and observe the wheels and the tracking of the trailer in reference to your tow vehicle. Brad

[Sailor Chlud]

Thanks Folks - I have my work cut out for me this weekend!

[ctenidae]

I can't add anything useful, so I'm going to suggest it may have been an earthquake.

Either that, or a loose hub/bad bearing.

[GreenLake]

I can only contribute first hand experience of what happens when the bearings get so bad that they freeze while driving.

It was most impressive sound effect with burnt rubber smell. Luckily for me, the bearing parts were by then ground to such small bits, that the wheel began to turn again and I was able to tow the trailer back home (about 1/4 mile - lucky that one, too).

[Sailor Chlud]

Thanks to everyone with your helpful suggestions - the problem was resolved by removing the hubs and installing new seals, then re-installing the new races and bearings that were in there. I think one hub had the races improperly seated and there was play in the hub. After reinstalling everything, the trailer rode nicely at highway speeds, so we are good to go. Thanks for all your help!