Like clinesr said It's most likely a balance issue. I have had this on the front before. I think the MPH that I read years ago where you will feel unbalanced wheels is between 65-68mph. It should get worse and may even out a little when you go under or over those speeds.
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Typically when i replace suspension parts i would recommend both ie tie rods. But there are actually 4 tie rods. 2 inner 2 outer one of each on each side. Not trying to insult your knowladge on suspension. But your ball joints may also be worn. And well as your hub assembly. If you do some research look for a shop that has a good name and maybe even try auspension specialist
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