go down to the hobby shop and tell scott or nate to hook ya up with one. tell them not the magnetic ones . jimbo rod and i are using the same ones from down there and they have boxes of clay that will last you a long time.
makes a BIG difference even in the way the truck jumps, in the air. dont remember the company but they know which one. ive been using a car hub to place between the cones because the hole in the rim is bigger than the cones