I have notice to dangerious level. My car sorta swing very much on road crown. For examlple
1. If there is crown pull on the raod; its almost impossiable control back.
2. I have notice an inch play in steering
3. When ever car come out of bumps; it will try to go out of control
I do have odd tire setup,; but it was doing before too.......
I have now
Front 245-50-16 Dunlop
back 225-60-16 (Snow Tire) Dunlop Graspic(Winter Tire)
I had same problem when I had 285-40-17 GoodYear F1.
I think I need to get check out aligment.
Car can go straight with steering wheel straight.
there is no known wear and tear.
any ideas ?

 

It feel like I have too much postive caster
cause I feel that its happens at 70Mph

 

 

hmmm
What about Caster. u think caster can cause that ?

 

Anything is possible, but IMO, no.

Positive caster should help, not hurt. Zero or negative caster, which I don't think you can get within normal adjustments would make it almost undrivable.

Unevenly worn front tires and/or lots of toe out would make it darty.

Get it to a good alignment shop.

 

That mean NO dealer and Firestone places ?

 

I don't know about Toronto, but my Chevy dealer is good. Generally GM technicians around here are paid better than the guys in the Tire and Muffler shops, are more highly trained, and often do a good job.

I always ask for (and receive) a print out of the "before" and "after" alignment specs on my car.

Good luck.