Assembly instrumented for rocket axle and mounting METHOD

An assembly for instrumented stub axle comprises a stub cap (26) having a bottom (26.1) provided with at least one hole (26.3) and a skirt (26.2) defining a geometric reference axis (ZZ) , the skirt having a distal end (26.6) opposite to the bottom face and constituting an axial bearing, the spindle cap having a larger outer diameter D1, and a magnetic encoder ring (36) secured to either a support (40 , 50) fixed relative to the spindle cap (26) having a diameter D3, in axial overlap with the spindle cap (26), either directly to the spindle cap (26) and has an outer diameter D2 less than D1 and / or D3.