Since this old thread got bumped, I'll add in some Tri-Z hub details, based on post #13 they should fit the 225DX and quite a few other machines.
1985 Tri-Z hub measurements:
Bolt pattern: 4x100mm
Spine size: 25mm
Hub thickness (where it interfaces with the splines on the axle): 43mm
Offset: 8mm from axle bolt surface (inaccurate measurement with caliper + eyeballing)
The Tri-Z hubs fit on a 1984 TRX200 rear axle, and also a 1984 ATC200ES axle.