Tires: New tires and car vibrates, cv joints, steel rims

Question
I brought my car into the dealership to get some winter tires and steel rims put on. After i got my car back and was leaving i found that my car was vibrating. It wasn't vibrating all the time but seemed to do it mostly when i was decelerating. So i went back to the dealership and they said that when you get new tires the air in them can settle creating an unbalances tire. They said after driving it would go away. So i drove around for 20 min and i guess i could say that it improved but it all seems weird to me. I live in Calgary Canada and it has been really cold which might make the air settle i guess. Really i just want to know if this sounds like a possible reason for the vibrations because i have never heard of this before.

Answer
Tim,

There are a couple of possibilities:

1)  Flat spots.  Tiresd that sit in one spot for a long time tend to deform to the shape of the object they were against.  If it is the road, then a flat spot will form there.  Taking a hot tire (one that has just been operated) and allowing it to cool aggravates the situation.  Of course the longer a tire sits in one position, the stronger the flat spot.

You can sometimes drive these out, but it generally takes an hour of high speed driving to really affect it.

2)  You mentioned steel wheels.  Sometimes these are designed to fit on several different types of cars, so the center hole of the wheel isn't machine to snugly fit on the center hub.  This means the wheel is being centered only by the lug nuts - not a good way to do this.  So the wheel might be mounted off center.

3)  But what I really think is going on is you have a drivetrain component going bad.  The clue is feeling it mostly on deceleration.  CV joints or u joint probably.  The change in tires just aggravated the situation - plus you started looking for any signs of a change.

Hope this helps.