Last time I was at the track I noticed some vibration at high speeds. Specifically, above 90mph or so it feels like I'm going over a washboard surface. It's right around a resonant frequency, and at higher speeds the rear view mirror is bouncing so much it's unusable and seems like it will depart from the windshield. Needless to say, I don't think this is normal.

Someone I was talking to mentioned that if the alignment is off, the wheels can start to skip at speeds. Is this a possible problem?

The vibration is completely unrelated to engine speed - just road speed. I was also thinking it could be the driveshaft, but I can't imagine that would be enough to vibrate everything badly (though I really don't know).

Ideas?

-=Russ=-

 

Could be bad tires, tire pressure, alignment, bearings, and yes the driveshaft. However, driveshaft vibration is usually load dependant. My guess is its not that.

-Joe

 

Check for uneven wear in the tires and check the pressure first. Then I'd rotate and balance. And if that didn't work, align.

 

Ball joints- mine started right at 90 also...

 

Hm... how much of a pain are ball joints to replace?

I haven't rotated the tires, but I keep them properly inflated, and they don't *look* like they're unevenly worn. I doubt they're balanced though. I should take them in to a shop to be balanced. I want to replace them because they're old (and somewhat cracked around the edges), but I can't afford new tires right now, and they still have a lot of tread left on them.

-=Russ=-