So I went on a Poker Run this weekend. When I got about a 1/2 mile from my house on the way home I noticed a new sound. It is a humming sound that coincides with the wheel speed. I really start to hear it at abour 30 miles an hour. If I had to guess I would say it sounds like a bearing? The sound is unchanged by letting in or out the clutch and seems to be directly related to wheel speed. Are there little bearings in the wheels? Are they hard to replace?