So, I swapped out my summer tires for winter ones over Thanksgiving and since then I feel like the ride of my car has changed. Sometimes at around 55 or 60mph crusing on the highway I can kind of feel a rhythmic vibration underneath me. The weird thing is that I don't feel that at all in my steering wheel. My steering wheel doesn't wobble and stays perfectly calm. I only feel the vibration underneath my butt and my legs. I can't tell if it's just the road causing the car to kind of bump up and down (only at certain speeds though?), or if it has something to do with the new wheels or tires. I bought used stock wheels from another forum member and put a set of Michelin Pilot Alpin Pa3s on them. Should I get them checked out or am I just being paranoid? Sometimes I think I'm just being over-sensitive to it. Ideas anyone? Thanks!