Wow just my luck!

 

60-70 MPH usually would associate with a balance issue, either tire/wheel or hub/rotor. I would clean all of the tar, mud and rocks off the inside of the rim.

 

Hub/Rotor were both good. I will take a look-see at the Tire/Wheel. I have known of 2 bent rims on my car, but with this problem I am having as being intermittent at the speed mentioned and not constant like the vibration I feel from the bent rim.

 

Surely there must be more suggestions. Come on guys..

 

A bent rim can cause intermittent oscillations in concert with another bent rim, as they can go in and out of cycle with each other. Kind of a sympathetic vibration. Hopefully that makes sense. :)

 

Sounds like a wheel out of balance.

 

@whopper as intermittent as when it's cold, nothing, when it's warm out, all the time?

Or going around curves it dulls down, and when going straight it gets worse?

@Twistedtat, that is something I have considered, but given the above mentioned symptoms, it has me wondering.

 

Swap the tires, front to back, back to front. If the vibration changes, then you'll know it's a tire or rim issue.

 

Rears criss-cross, and fronts roll straight back, right?

 

I wasn't saying rotate the tires. Move fronts to back, backs to front.
That way, if it's a tire or rim issue, it should be easier to determine.