scrubs

Just bought a second hand set of tyres for track use and they have a blue tinge all the way round. Heard this is caused by heat cycling and overheating and that the rubber will have hardened and lost some grip. But also heard this will scrub out Am I safe to use them on track or should I bin...

Really a question for Badger and the likes. What should I be looking out for when buying track day scrubs off of ebay? Any tips? What sort of price do you think is fair? I'm assuming Supercorsa Pro's or Racetecs are the way to go, soft front medium rear :dunno I see a certain marktalbot has a...