I just called the company that makes these balancing beads. I was told that tires with an aspect ratio less than 65% require both weights and beads. They sell standard beads that will fit through the valve stem, and larger "off-road" beads which require breaking the bead for installation. The price for 8 ounces which is enough for a large 4X4 tire is around $19 plus shipping. Canadians can purchase them here-->
http://www.pjf4x4.com/store/index.php
Dan