Abstract: A collapsible shaft assembly forming part of a universal coupling, such as in the steering system of a motor vehicle, has outer and inner sleeves, a co-axial elastomeric sleeve in radial compression there between, a shaft rotatably coupled to and axially slideable within the inner sleeve and a shearable lock to hold the shaft axially relatively to the inner sleeve up to a given, minimum axial load, such as in a motor vehicle collision.