Axles and spindle assemblies for wheeled vehicles. More particularly, in at least one embodiment, this invention relates to a substantially curvilinear axle for wheeled vehicles, alone or in combination with a spindle assembly, having a substantially continuous radius of curvature extending from one end of the axle to the other. In at least one additional embodiment, this invention relates to fabricated spindle assemblies having gusset arms for mechanical attachment to axle ends.