Tubeless 19.5" wheels are direct replacements for an 18" tube type tire and wheel setup. Around Nashville, the older bread trucks built on a 1 ton chassis used to run them, for some reason. Probably because roadside tire changes were quicker- - - - -leave the wheel mounted on the truck, pry the flat tire off and install the new one, and use starting fluid to pop it and create a bead seal so it could be aired up the rest of the way. Much faster than removing the wheel and fighting with a sectional wheel!
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
Love your enemies and drive 'em nuts!