Hi all,
My car: 2006 Chevrolet Cobalt SS/SC w/ 24,500 miles on it, mods in sig.

I have a very strange problem, going down the highway (and I tried this in at least 20 different places on the highway) at 70 mph the car rides very smooth and stable, however, as I climb to 80 mph I can feel shaking/shuttering in the steering wheel (and you can see it in bottles of water I had in the car) however, as I speed to 90 mph the shaking seems to start diminishing and at 95 mph it is completely gone and the car rides awesome!

I am very confused as to what this could be. My only thoughts were unbalanced tires or perhaps the rear spoiler (I have the high rise) causes shaking at high speed, however, the higher you go the faster the shaking so you don't notice it as much?

Any thoughts, I'm going nuts!

 

Most likely unbalanced wheels

Kevin

 

yea un balnced wheels

 

Do you know why I would feel it at a certain speed? Definately glad it's just the wheels!

 

Guessing its the wheels

 

Yes at a certain speed the wheels are spinning at a frequency that causes the vibration. Common problem and cheap.

 

Just have the wheels re-blanced ...

 

What happen is the ss\sc uses stick weights.
One can fall off (only held on by 2 sided tape) and knock out your balance.

I had that happen and had tires rebalanced and shaking went away.
Sound like the same problem youre having

 

Definitely wheel balancing. I would suggest taking it somewhere that road force balances. Much better way to be balanced as they will line up high and low spots on your rims and wheels to get you the best possible ride.

I had bad vibrations and it turned out that my wheels were no longer round. They were balanced, but the shaking never stopped.