I've Got a Wobbly Butt

[sfsvx]

Not mine, the SVX. I got in to drive it after a few days of the car sitting idle, and there was a noticeable wobble (I can't think of any other word to describe it). It moves the whole car but doesn't really affect the steering wheel, which is why I think it's in the rear. It's the same sensation I've had with an out-of-round tire, but that came on gradually and this was not there one day, there the next. It's also similar to the side-to-side motion when my Explorer goes over bumps.

There aren't any new noises, rattles, groans, etc. - just a wobble - and my visual inspection didn't find any parts falling off. Except for the wobble, the car drives just as it did before.

It's really noticeable at speeds below 30. From 30 - 65, it smooths out some, and above 65 it vibrates noticeably, just like an out-of balance tire.

I'm away on business and can't get it looked at yet. Anybody have any ideas of what it might be? Tires? Drivetrain (please, God, not that!)? Should I not drive it and have it towed to be looked at?

Appreciate any insights, as usual.

[mattski]

I would check to see if the lug nuts are all tight and that there is no mud or other stuff stuck to your wheels anywhere, including inside.

Matt

[CigarJohnny]

It really sounds like a tire I had on my wagon. Did the same exact thing and came on suddenly. Have you hit any potholes lately or large rocks on the shoulder? It only takes one bad hit to create a bubble in the tire and it feels exactly like you described. I drove on mine for a while before I replaced the tire and eventually I could look at the tread and see where the bubble was due to the thinner tread depth at the bubble location.

An easy test would be to raise the rear tires off of the ground and slide a block close enough to the tire for it to lightly graze it while you turn the wheel by hand. If there is a bubble it will hit the block before the rest of the tire. If it is not out of round anywhere it will touch the block evenly around the tire. It's a quick, free test to try if you can see no other loose fittings or things on the suspension.

[immortal_suby]

Lug nuts are my first guess too but also check the tire pressure

[sfsvx]

Thanks to all you guys who took the time to respond to my paranoia about all things SVX. My departure was delayed, so instead of romancing the wife, I jacked up the SVX to look at the tires.

The lugnuts weren't loose - in fact, I think whoever put them on won the "whose air wrench has the most torque" contest. The right rear had developed a tumor on the inside half of the tread, about 10 inches long and probably about an inch high. I looked through the PO's records, and these tires were mounted in May of 1996, at 41,000 miles. 5 1/2 years and 58,000 miles later, there's plenty of tread left but I think the Texas summers and sunlight took their toll.

When I got the car this past August, the tires were Armor-Alled, which hid the numerous little cracks all over the rubber. Now it's worn off, and the tires look their age.

It's Yokohama AVS Dbs for me!!!

Thanks again for the help.

[CigarJohnny]

Glad you found the problem right away. Tires can suck. At least you didn't buy the tires when new and have to see them get messed up. It's easier when they were already on the car. Somehow it makes it easier to swallow replacing them all. Good luck with the new ones! Make sure you get the road hazard warranty in case it happens again. It's the only way they will warranty such defects because they claim you only get them from potholes and such.