Posted by Jack Smith on May 12, 1998 at 16:59:29:
Reading over the various posts on rims that have appeared here, I fear that an uninitiated person will be injured due to confusion in terminology. There are two very different types of rims in common use on power wagons and military trucks. I hesitate now to refer to any of them as "split rims" because the two have been mixed up so often. I don't have any good scanned photos of the two types, so maybe someone can find these and place them up somewhere so everyone can take a look? One of these rim types has two half-rim sections that bolt together. This is what I traditionally called a "split rim". But I hear this term being applied to the other type of rim, the budd wheel with lockring. If you believe you have read safety instructions for a lock ring rim, and you proceed based on that, and it turns out you really read about a two piece wheel, you probably are going to be confused, possibly hurt. So, in an attempt to clear this up, I thought I would get this thread going. The lock ring type of rim seems to be more common, and this rim has only ONE bead flange, allowing the tire to be slipped onto the rim with ease. The lock ring forms the other bead flange, and fits into a groove in the rim where the other bead flange would be. It snaps into this groove with spring-loaded authority, and holds the tire when it is inflated. The danger arises when the bead seats, the tire forcefully expanding against both the fixed flange and the lock ring. If the ring groove is dirty or rusty, or the ring is not seated, or if the ring is deformed, it will let go of its hold in the groove and fly off like a missile. The ring itself has a machined slot in one inner end, for use of a special tool that usually comes on one end of the military tire tool. It looks like a bent flat hook, about a half-inch wide. It's supposed to be used by placing this hook into the slot and carefully prying the ring out of the groove on one end, much like a snap ring from a shaft. Once the end is free, one works around the ring carefully, bringing the rest of it free of the groove. It is here that most rings are bent or deformed. The rim can even be damaged, if the ring is pried carelessly from the groove. Once the ring or the rim are damaged, they are scrap. If your ring does not sit flat on the floor, or very close to it, don't attempt to reuse it. If the ends obviously are not going to meet at the same plane when its mounted, don't use it. If it slips out of the groove when you try to seat it fully, it'll also slip when the tire is inflated. As for the two-piece rims, they are simply held together by a circle of studs and nuts, each rim half having one of the bead flanges. I cannot imagine anyone removing these nuts and attempting to dismount the tire without first deflating it, or reinflating it without protection. But often, someone will forget to run the nuts back home before inflating. I have seen some unfortunate things happen due to confusion. Anyway, for safety, please have these tires dismounted and remounted at a good tire shop if you don't have the equipment and experience to do it properly. Neither type should be inflated without restraining and guarding the whole assembly with either a cage or a mechanical restraint chain or bar of some sort. While the lock ring was intended to allow tire service in field conditions with simple hand tools, the trucks we are fooling with here are all very old and worn, so why take a chance?
Regards,
Jack