There’s a lot of talk about how to carry your fatbike on your car, with tons of custom jobs and modifications out there. Maybe I got lucky and had the style that works with all bikes, but after driving thousands of miles this past year with two fatbikes on my roof, I can say the Yakima Raptor roof-top racks work very well with fatbikes.
The only thing you have to change are the wheel straps. Take off the plastic factory ones and use nylon webbing with buckle straps or the orange ski straps. Done. Solid. Drive and forget about them.
Even with my 100mm wheels, the tires seat down in the raingutter track well enough to stay in place. If you encounter massively strong crosswinds, like blowing 50 mph in the Alaska Range, also strap the wheel to the rack arm that holds the downtube. This will keep the wheel in-line and from turning in the strong winds.
Surly downtubes are much friendlier than the biaxally ovalized downtubes of the 907s and Mukluks, as they are smaller diameter and uniformly round, which fits in the clamps a little more securely. Not a major concern, however, as the clamps still have bomber purchase on the wider tubes.
The racks also work well with other eye-catching items you might put on your roof, too.