[jocko]

There were locking rings with and without the break, you just happen to have both. A semi-truck or tractor repair shop is usually the best place to swap tires with those types of rims at a reasonable price. Some places won't work on them, but generally speaking, any place with a cage and that isn't run by 18 year-olds can do it. They can be dangerous, thus the cage or "chained" approach to changing them.

Not to hijack, but closely related to the subject - the use of bias-ply tires vs radial tires (on these older rims) has been a hotly debated subj in some forums - and I still don't know the right answer as I've never seen proof in writing of the opinions - other than "it hasn't killed me yet.." proof.. Clearly these wheels ran bias plies when new, but I've seen some statements about radials having a slightly narrower or at least different lip/bead than bias plies. I "suspect" someone was mixing the locking ring discussion up with the old 16" vs 16.5" tire discussion (because they do have distinctly different lips) - but does anyone have anything definitive instructions/references, etc as to whether it's ok or not ok to run radials on locking ring type wheels? I've always kinda wondered... I "think" the answer is yes, as long as radial tire tubes, boots, etc are run. But I just don't know for certain.