Hummer H1 Beadlock Shims
When the bead of the tire is significantly higher than the rim it's necessary to insert shims so the locking ring will seat flat against the bead. If you don't shim the wheels you won't be able to correctly torque the beadlock ring down and could possibly bend the ring. The amount of shims varies from none to around 3 for the thickest off-road racing tires. The shims are .090 inches thick. The shims generally cost 20.00 per wheel for a single row. The 12 spoke racing wheel shown below ended up using 2 rows of shims per wheel.
The 12 spoke beadlock wheels allow for about .5 inches of bead thickness. The standard wheel allow for .375 inch of bead thickness. When you tighten down on the bead of the tire you will get a certain amount of 'crush'. The ideal crush amount is approximately .125 inches but you can tighten the ring down to get as much as .180 inches.
Lets say you have a tire that has a bead thickness of .740 inches and you want to install it on a standard wheel. . You take .740 less the standard wheel allowance of .375 less the crush amount of .125. This leaves you with .24 to make up. 2 - shims at .09 each will get you .180. So .240 less .180 still leaves you with .06. You can make up the difference by tightening the ring down to get a crush of .180. You would need to order 2 set of shims for each wheel.