xrtime, what tires does your roadster have? PS2's or Continentals? The reason I'm asking is that the PS2's have deep in-line grooves that can sometime track with imperfections on the roadway -- kind of like what can happen when you drive on a section of road that has rain grooves cut into it. I have noticed this from time to time when pulling up to stoplights, especially if the road is badly rutted by truck traffic.