your right barry in that dirt changes so much that one week prep 'a' works great, but the next week it doesn't......tires aren't dirt or aspahlt specific (at least the ones that i've ran!), but you have to keep different sets for the type of prep that you need. aspahlt on the other hand, get some heat into the tires and they don't necessarily need any prep at all. i have used some and felt the differences and i believe that SOME prep is good....not to the extent that i've seen dirt racers use, but getting the tires to fire right off is important whether on dirt or aspahlt. i've found that just a simple shot of wd40 or simple green helps to fire off at the drop of the green.....
jncyall....i race at watermelon capital speedway in cordele...granted it's not a road course, but it's a BIG oval and you get plenty of seat time!! not to mention that it's down right fun!
as far as dirt and asphalt tracks....historically, dirt tracks have been around a lot longer....most were created to fill the need for racers to have a place to go....so farmers cut tracks in the back 40...paving a track didn't come along until years later. most of it was cost to lay the foundation and paved the dang thing....and instead of this expense, tracks elected to stay dirt.
racing on pavement or dirt....well each have thier advantages, but when you really get down to it...racing on pavement can be said to be a precise, calculated and straightforward style of racing....whereas dirt? there is a lot to be said for slinging dirt, hitting a corner and slamming the kart sideway, drifting through the corners with the rears throwing dirt everywhere and watching the driver work the kart......
