All right. I've searched and can't find an answer specific to my problem.

Had the car a couple months. Previous ownerlowered the car with coil overs.Don't know what kind.

Since I bought the car there's been aknocking noise from the right front wheel ifI go over a big enough bump. Not a big deal. Most of the time I don't hear it. However, if Iget the carover 70 MPH, the car starts tovibrate. Thesteeringwheel itselffeels smoothas silk, but the car is definitely shaking. I have no clue. The shake feels like it is also coming from the front right wheel. Is it an upper control arm? Lower control arm? Bushing?

Any ideas?

Tire/wheel out of balance? You could switch your two front tires and see if it moves to the other side.

Tires out of balance would shake the wheel, no?

not always, i did donuts in the wet for awhile and on the way home i went over 70mph my car shaked leaving the steering smooth but it went away... deff the tire, check for bald spots. u may need a new tired or a balance. probably not the suspension though which is a good thing

Upper control arm perhaps?

I'm voting for the off balance tire.

im pretty sure its not the arms...check by lifting the car on the jack and shake the wheel... if it shakes then its the control arms....