Old Man Mountain Rear Fit Kit – 169 – 178mm Thru-Axle M12 x 1.5. Upgrade from standard eyelet mounting to stable secure and reliable axle mounting. In addition to many eyelets being made for the minimal weight of fenders eyelet mounted racks rely on the strength of M5 bolts loaded in shear Old Man Mountain Fit Kits provide a low captured mounting point at the axle. Pucks provide a secure upper attachment point for the rack and attach with high strength UV stable zip ties. Safe for carbon steel titanium and aluminum bikes and forks.