I have gotten asked to make a John Deere tractor for a girls graduation cake. I have all the ideas I need to do the tractor but not sure on how to do the wheels and to make them really look good. I would really like to make them look like wheels but not sure if it can be done out of buttercream and don't want to use fondant. Can anyone help???

Maybe you could use a FBT (frozen buttercream transfer)? Hope that helped!