Well after seeing a couple of my buddies really do a double take on my beadlocks, I realized not many people really understand them. We all know they clamp the tire to the wheel, but its different to actually see it.
Here is one of my beadlocks wheels:
This is with the tire mounted, you can sort of see the tire bead in between the wheel and the beadlock ring:
All 32-bolts removed:
Once the ring is removed you can see the tire bead rests underneath the ring, but on top of the wheel:
This is with the tire removed, you can see the flat mating surface on the wheel for the tire bead:
For comparision, here is a standard wheel:
Side by side, a beadlock wheel and a standard wheel.
This is a closeup of a beadlock, I have spacers in there to simulate the gap of where the tire bead sits:
Close up of a standard wheel:
Ok, so that should clarify how they work, now why do you need them? Beadlocks do allow you to air down farther without blowing a bead, and they keep the tire from spinning on the wheel. However there are also other things to consider. One is weight, most beadlocks wheels are going to be heavy, adding unsprung weight, the ones in the picture weigh in at 43 pounds each, just the wheel. They are also quite a job to assemble. This is my stack of 128 bolts, all of which will be torqued no less than 10 times each, many times much more than 10 times each, to get an even clamp, and for the bead to seal.
Now that I have done it several times, it still takes me one solid hour of torquing, per wheel, the bolts to 12 ft-lbs, to seat the beadlock ring.
Personally I've never been hasseled over my wheels on the street, and the fact is there is no specific law against them (Here in my state at least). Next some say they are not DOT approved, however, niether is any other wheel sold here in the USA. Wheels generally don't carry DOT approvals, tires do. A quality beadlock wheel will not leak, and can be run daily if you so wish.
There are other options vs. buying beadlocks. You have two options too that will allow you to use your current wheels. [URL=http://bbb.quadratec.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=44;t=002282#000000]Kwrangln has a good post about making your own beadlocks. Your other option is internal beadlocks. [URL=http://www.ok4wd.com/product.asp?id=797]Staun Beadlocks are a common example of internal beadlocks.
This post will show the mounting procedure.