an improved polymeric knuckle pin with at least one indented area that elastomer rings rest in . the indented area is strategically placed in an area on the shaft of the pin where the coupler - knuckle connection exerts impact , force , and stress on the pin . the elastomer rings in the indented area provide cushion to the pin from the impact , force , and stress , allow the pin to avoid hard contact with the coupler and knuckle , distribute the loads exerted by the coupler and knuckle more evenly , realign the coupler and knuckle positions , and protect the pin itself from surface cuts and scratches . the elastomer rings on the shaft of the pin improve the life of both the coupler - knuckle assembly and the pin .