[s-cars] Problem vibration in the front end?

[colin cohen]

I am experiencing an odd but very pronounced front end vibration with my SQ and wonder if anyone has experienced the same thing with an Urq?

It starts at about 60/65 and gets progressively worse with lots of wheel-shake up to about 80 and then reduces somewhat but does not disappear;

Almost undetectable when I drop below 55/55.

Here is what I have eliminated: swapped wheels and tires - completely different sets; new shocks and upper strut bearings (same as Urq); checked for tie rod integrity which seem tight with no play; and checked for bearing play.  There is a slight oscillation when braking as if the rotors were warped but no run out when tested on the car.

Any input gratefully accepted.

Colin