Fatbike Fork mount Carrier Kuat Dirtbag 15x142mm - BlackFatbike Fork mount Carrier Kuat Dirtbag 15x142mm Black The Dirtbag is our down and dirty bike rack, a compact yet robust solution for cyclists that's affordable without being cheap. Simply bolt this accessory to the truck bed, floorboards, camper shell, or other suitable surface, remove your front tire, and secure your bike with a compatible thru axle or skewer. With eight size variations, the Dirtbag is the accessory you want on every trip.