I had the same issue
I have a roof-mounted SportWorks rack and when I got my Rig, I couldn't (at first) figure out why it wouldn't fit. If you're having the same problem, you're not able to swing the retention arm up and over the tire...right?
If so, the trick is to extend the ratchet all the way, put the bike in the rack and lean it slightly away from the arm mechanism. Then swing the arm straight up (90 degrees to the tray) and THEN pull the bike and tire under the retention arm. Then secure as you would any other tire.
Hopefully this makes sense. Again, if you're having the same issue, once you figure out the lean-swing-straighten-secure it's pretty straight-forward and the bike DOES fit. And you're lucky...my rack is on top of my Montero. I'm tall, but that's still a long way up there.