I have some 215's on the front and 225's on the back with 2 differnt tread patterns. The car had an alighnment about 2000 miles ago but at speeds over 60 mph the steering wheel has a slight shake to it.

Could this be due to the 2 sets of tires or no?

 

as long as you have the same tires side to side you are ok, a different tread pattern from side to side can cause a pull and possibly a steering wheel shimmy.

Its pretty safe to assume that you have a wheel/tire balancing issue, possibly some RFV (road force variation) as well.

Go to a shop with up to date equipment and get your front tires balanced and checked for RFV.

 

yeah, fronts are both the same and rears are both the same. So a balance issue then? never heard of rfv...

 

RFV is basically a "hard" spot in a tire, every time that spot hits the pavement it can make a noise and vibration. Think of an egg rolling, and the hard spot being the tallest point.

 

Have a good tire shop do a road force balance. That is the only way to see if one tire has a weak spot that can be causing the vibration. It can happen on a perfectly balanced wheel.