Originally Posted by
dabac
Best assumption I can come up with from the pic:
Your rear hub is probably not entirely symmetrical, with one flange being further inboard than the other. If they'd laced the most inboard flange to the same side row of rim holes, maybe the spokes had ended too close to vertical for a reliable build.
So they laced the most inboard flange to the opposite side of the rim to get a better lateral (sideways) spoke angle.
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I think you may be onto something. The gear side does look off-set. There's at least the width of a locking bolt (or 2) difference from the "other side"....perhaps to gain some clearance from the fork(?)