make sure the tire is on tight.

if it still wobbles, remove the wheel, deflate the tire, remove the tire and the tube. put the rim back on without anything and spin it again. see if the rim needs to be trued(straightened) or rebuild. if it spins freely and true, check your tube for any odd looking things or shapes or deformed parts. do the same with the tire itself. put everything back together.

if you still can't find the prob. i'm down to learn from the real genuises here.