vibration

DGW · 10-06-2010, 08:22 AM

I drove the car yesterday, and 08 987, and noticed a vibration that I don't think I have ever experienced in a car. I suspect its tires but on the off chance its something more serious I though I would check here.
It became most noticeable around 60 mph up through 70 which is as fast as I went. It would start in my feet and come up through the seat. Then it went away and started over and continued to cycle like this.

Its not the road, I've driven other cars on the same road without anything like this. We took a 3000+ road trip about 3 weeks ago and this vibration did not occur. I had new rear tires mounted on the car before the trip. The tires are Continentals.

Flieger · Flieger's Garage

Sounds like a harmonic vibration caused by the tires. Maybe a wheel weight fell off?

DGW · 10-08-2010, 09:34 AM

I hate problems that fix themselves. I drove the car again yesterday on the same road and most of the described vibration was gone. I still have a bit in the steering wheel but the cycling quit. I probably need to have all the wheels balanced to see if that provides a permanent solution.

BYprodriver · BYprodriver's Garage

Tires do not go in & out of balance. If the car is not driven for days especially when it is cold they develop a flat spot that will cause vibrations until the tire heats up. When a tire is slightly out of balance the vibration occurs at a specific speed range, usually around 65mph.

Grant Lenahan · 10-20-2010, 12:07 PM

maybe some dirt or other material got on the inside rim - and now washed away?

Grant

DGW · 10-22-2010, 03:09 PM

The solution was 15 oz of weight added to one of the front wheels. There is no explanation for how or why it was out of balance.

Grant Lenahan · 10-22-2010, 03:35 PM

15 Oz? A pound? On one wheel? That's obscene. Are you sure? not 15 grams? Or 1.5 oz?

We can only assume either something fell off, or belts have shifted, or?????

Grant