Could be an out of balance wheel too. I've had that happen a couple of times. and the vibration comes and goes at the same road speed.

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1978 Ford F-150 351M
2002 Kia Spectra 1.8l 5-sp
1985 Volkswagen Scirocco 8V 1.8l 5sp
1985 MB 300D Turbo California

"Die Natur verabscheut Vakuum"