275/80R22.5 was introduced by Michelin. IIRC it is (was) a european size. The equivalent sise is 295/75R22.5. Both tires carry the same load at 110psi (G Load range) or 120 psi (H load range). Both tires are, for most purposes, interchangeable.
Over the road trucks are using both sizes. So demand really depends on if there is a glut of casings in either size.
Tom, Patty, Hannah "The Big Dog" and Abby Kat, Indianapolis, Indiana 2000 36' FDS 72232 Our Photos
We live out in our old van. Travel all across this land. Drive until the city lights dissolve into a country sky, me and you - hand in hand.