i had similar problems,in the end i took it to a 4x4 centre who have a state of the art wheel machine,2 wheels that kwik tit said ok were miles out and needed re balancing,the other 2 the tyre fitter marked the tyre with chalk using the tyre valve as a guide took the tyre of and rotated it 180deg then refitted and balanced it,not had a problem since they were done and that was a few good weeks ago now.