Robinson Racing Top Shaft,2 spd 17/22T:TMX RRP8525 Robinson Racing Steel Top Shaft 2-Speed 17/22T is constructed of hardened steel 2-Speed Top Shaft for the T-Maxx. One top shaft, and one 6x11mm bearing are includedThe included 6x11mm bearing fits over the threaded end of the topshaft. One of your 5x11 bearings (that you already have) will be needed for the other end of the topshaft. Please note that if you are running a double disc slipper, DO NOT use the spacer be