There are a couple of companies that offer fatbike specific racks, but these guys tout their environmental responsibility and their products are in CAD not USD. And it can hold up to 100lbs . . . not sure how 15psi would hold up to that though. 
There are a couple of companies that offer fatbike specific racks, but these guys tout their environmental responsibility and their products are in CAD not USD. And it can hold up to 100lbs . . . not sure how 15psi would hold up to that though.