Problem after tire install

Took my Nomad to a after market shop this past Friday to buy a new front tire. I bought a Kenda Kruz673 150/80/16 . Things seemed fine until I went for a ride today on the Interstate. All is well up to 60 mph, then, I start to feel a distinct vibration. Not a shaking like the tire is out of balance, but a vibration. I can feel it in my feet,legs, arms, and head. My wife says she doesn't feel it, as we were riding two up. I do. Maybe it is just the Kenda is a harder tire, and I am feeling every little bum in he road ? I don't know. What say you guys ?