sorry derek, i am absolutely dead wrong - like you said pinto's use a maxi swingarm. I wonder if there is something about a pinto that would allow them to work with that swingarm though?
when i went to put em on the maxi in the back, the jammed right in the swingarm where it comes together, in the middle like a wishbone, and that was it, it held the tire fast with the 2.5 but the 2.25 were totally fine.