Different tires hole shots and knock offs are junk from my experience on the 500. My bike turns them into oiled racing slicks no matter what surface I'm on for the first 3-4 gears. I've found for wet slippery terrain a heavy 6 ply "mud" style tire hooks up good if you have 1-2 psi in them. A great hooking tire for the rear is the ohtsu mr501's which came stock on 400ex's and can still be purchased for about $150 a set and will require a 9" rim.