Measure the drum ID first. The old rule of thumb on refinish/discard drums was .060" oversize for passenger cars, and sometimes .090" for pickups, assuming the truck had the usual heavier-duty drums installed. If the drums are at or near max diameter, you might consider just machining the lip away, not taking a full cut across the drum surface.
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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