I ripped a foam on of my stock SS wheels (HPI Warlocks with the Dirtbonz tires) and had severe wobbling too. I just ended up junking the tire and foam, and bought a new set of wheels and tires. But, if you want to fix it, you'll need a new foam, and you'll have to remove the tire off the rim. I would boil the tire in water to remove it from the rim.