Any suggestions for how to carry a B.o.B. Yak (or Ibex) on a roof rack? I drive a small station wagon and the trailer is a bit big to fit comfortably in the car with our other gear when we travel with the bikes.
The yoke spacing on the BOB Trailer is quite a bit wider then a typical front fork mount bike rack, you could probably modify one with wider spacers and use a trailer skewer (or similar fabricated part) to mount the trailer yoke. The wheel tray will need to be long enough for the span of the trailer and the fork mount will need to be high enough (or the tray low enough) otherwise the trailer will stall on the wheel tray when you try to mount the trailer yoke in the fork mount of the bike rack.
I had an extra roof top, frame clamping, bike rack on hand so I designed and fabricated a bracket that combines the yoke mounting of the trailer with the roof top mounting of the bike rack so it mounts to anything in the same way that the roof top bike racks mount:
First, get some tie-downs like these:
You can get them with different kinds of hooks on the ends, depending on what you have to attach them to. If you remove the flag and perhaps the front "tongue" frame (which attaches to your bike), the rest of it should be no problem to secure on top of the car. You could also remove the rear wheel to get a lower profile for the whole thing (then put the wheel in the car). If you keep the wheel mounted, tie a strap through it so it can't spin in the wind.