Suspension Question

[elemgee]

Hi. As I'm driving along at around 30-35mph, it feels like the car is bouncing up and down. Not dramatically, but its noticeable. it stops at around 40 mph or so, but then starting at around 70mph, I can feel some vibration in the front. I've had the tires balanced (by a place that used the Hunter GSP 9700), and a front end alignment, but the problem still persists. I've checked the front suspension - jacked up the car, tried shaking the tires side to side and up and down, but they dont move, and I dont see anything in the suspension that looks off (for insttance, no cracked CV boots and nothing underneath feels loose). I'm thinking maybe its either the tires, or the front axle. Any thoughts? Thanks.

Larry