Hi All, a few months back i replaced all my tires according to the spec and recently i noticed a strange problem when braking at highway speed ~60mph that the steering vibrates and once i am down to 40mph o do not see that issue, any information on this will be appreciated.

thanks

 

Normally brake rotors would vibrate at lower speeds too. But check them anyway.

Check for loose balljoints & bushings?

 

after reading about this and talking to a friend think this has to do with the wheel balancing , it has been 7k+ miles since i replaced new tires, BTW i replaced my brakes in 2007 Dec and at that time the rotors were resurfaced

 

If the wheels were out of balance, you would essentially see vibration at any speed, not just under braking. Since its only under braking as you say, chances are rotor(s) are warped.