In this schematic the "Nut, Flange M10x1" is used most often.
The most reasonably priced component used on the Sf 2010 Eu (streetfighter) 9151-2892a 026a Rear Wheel Axle is the Circlip 85x3.
Parts such as the 026a Rear Wheel Axle: Screw, Chain Link, Nut, Clip are included in the Sf 2010 Eu (streetfighter) 9151-2892a 026a Rear Wheel Axle parts fiche.