Have had this since my car got back on the road after its rotisserie resto.. Front end shakes from 37-41 mph. Kinda of oscillates for a second or two, smooths out, then does it again.. 4500 miles.. Have had the front tire/wheels balanced 3 times by different places.. Everything new, did use poly graphite for front end, including lower..

Smooths out after 41 mph and runs great up to 100..

Only thing not new were used front tires ( age unknown) that had 15 miles on them.. All three rebalancers checked the tires and called em good...

Any thoughts here?