Those are the 3 piece rims with a lock ring that is separate from the full circle bead ring. As long as you find a tire shop with an old geezer who respects their possibility for problems during inflation, they're perfectly safe. Once those rims are assembled and inflated properly, it's virtually impossible for the pieces to come apart. If the tire goes flat or gets more than a few pounds low on pressure DO NOT try to reinflate it. Break it down and reassemble it properly. That style of rim can only be used with tube type tires, and a heavy inner flap that prevents the tube from chafing on the wheel. They're VERY hard to balance.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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