Originally Posted by von_zoom
Never had that issue. You sure you do not have a rim issue, and not a tire issue. I would think that the tire would not move on the rim unless tire pressue was way down.
I don't know how your track is set up, but if you can avoid any offline driving prior to entering the pit from the track, it may lesson the amount of build up you collect on the tire. All of that should go away during the first or second lap when you go back on the track.
Usually a spin followed by a nice off road excursion will get the tread nice and clean.