A lower leg for a suspension fork has two tubes with, in each case, a receptacle device for receiving a stanchion tube displaceably mounted in the receptacle device. The device is deformable under an effect of a torque applied to the arm greater than that exerted by said drive shaft, and is capable of being placed back in the normal operating position by locked relative positioning of the arm and the drive shaft. The kit further includes a holder including a shaft and a hub including a receiving portion configured for housing a prosthetic valve. The brushes are triangular in cross section.