I believe Terry has hit it by pointing at offset, but in case this is not clear, it refers to the offset of the rim with respect to hub (really, the centerline between the two spoke attachment flanges, but that might make it less clear). The point is, it's a matter of spoke adjustment that brings the rim to center between the forks. Having said that, on my swingarm model, there is about 18-20mm between the inside of the left fork and the spoke flange (kinda hard to get to for a casual measurement). If this does not equate to conditions for a plunger I suppose someone will point that out.
Richard L.