paddle tire help.

I ride hill climbs in treverton Pa. the hils are old coal mines so they are loose stones and some rocks. I recently bought a paddle tire that was 2 ply for the hills. after one day of riding the paddles were starting to break down and had some big chuncks out of them. Does anyone know a good strong paddle tire that woud work for me? I know the one i have now is a 2 ply do would a bigger ply be stroger?
thanks

1999 yz400F