An autox type street tire would be a great choice but I don’t think there is much available above 275’s in 17" sizes.
something like an ra1 or r888 would be nice too and give good straight line grip and way more cornering ability than a drag radial. I think they have the same sizing problem though.
Caster on a wheel with no steering? I can’t tell exactly what the rear end is but it looks like a straight axle to me