Id have suggested checking , and if theres any doubt replacing, the upper and lower, ball joints, and using better shocks, I had a 1980, datsun 4x4 truck that had a bad vibration, at between 50 mph and 57 mph, that I talked to the dealership service writer about, he suggested replacing the ball joints, and shocks needed replacing, , but he wanted an outrageous price, too do the work,
(a couple hundred dollars back in the early 1990s)
I decided to price out the parts (less than $90 then at the dealership,then, and even less now )
( from rock auto,)
and do the work myself then have a local tire shop re-align the truck.
replacing the ball joints and shocks, and getting a re-alignment, and a tire balance ,completely eliminated the problem
(and yes Id had an alignment and tire balance done shortly before and it had no effect.)
http://www.rockauto.com/
you might try swapping the front tires with the back tires just as a test to see if anything changes and putting the car frame on a lift or jack stands and checking the ball joints and wheel bearing would be a basic logical starting point
https://www.amazon.com/exec/obidos/ASIN/B0028QGT86/ezvid02-20
https://www.costway.com/21pcs-ball-...ce-remover-installing-master-adapter-car.html