My car has recently began to shake around 60 MPH............I took it to a local shop (my last resort is going to be going to the dealer becasue i have had issues there) and had all the wheels spin balanced, but the problem is still there.....

The wheels nuts are torqued correctly.

the mechanic cannot determine the cause.........

any thoughts ?

thanks

2006 LT . owned from new........new aftermarket brakes and pads installed a year ago, left front bearing assembly replaced 4 months ago

 

Could be a bad belt in one of your tires. Rotate them to see if there's a difference. Aside from that, it is very possible, however much you trust your local shop, that there is still a wheel that is not balanced correctly. I've had both of these scenarios occur more than once over the years.

 

I was going to suggest tire rotation too, front to back, and see if anything changes.

 

Questions.......

Do you have stock/OEM wheels?

When did the shimmy start? After ANY installations?