The 4:1 steel ones were the ones I had my eye on ��. I'm in western Pennsylvania and it's nothing but steep hills and mud and I've made a track for my Tiger in the woods but once the dirt starts to cake up it slows the tank to almost a stop and makes maneuvering a real challenge. Also would it be wise to put the metal tracks on the plastic Tiger or would it cause it to bend and bow in a long run?