That old hooiser front is cool. I wouldn't mind having that tire. But I wouldn't pay much for it cause I know the kind of cracking your talking about. I have a set of rear hoosier tri-tracs that are weathercracked very badly to go with it!
Some where I have a pic of a custom tri-z front hub made of aluminum that was probably designed to fit a 10" rim like the one you got. Not sure who made it, it could have been home-made. The rim you have is probably just the honda 250R model from what was then mitchell, now douglas.
see if the guy can get you the pic of the hub he sold.
1986 Tecate
1984 Tecate
1985 Tri-Z
1986 ATC350X
1985 ATC250R (2)
1985 ATC125M (2)
1982 ATC70 - Original Owner
175 TriMoto Frame with Pro-Tec Rear Suspension
3-Wheelin' since '82