Abstract: In packings for hydraulic pistons or piston rods with a packing ring comprised of a tough elastic synthetic material as the contact packing between a stationary machine part comprising an annular groove and a moving machine part comprising an initial slope and of a rubber clamping ring clamping the packing ring radially and providing a sealing action with respect to the annular groove in the stationary machine part, an annular surface is located between the end face of a step at the high pressure side and a conical surface adjoining the latter on the low pressure side, which annular surface forms an obtuse angle with the conical surface of such a value that when the packing travels in over the initial slope the resultant F.sub.res of the normal force F.sub.N and of the frictional force F.sub.R halves the sealing edge angle. When using conventional materials and conventional angles for the conical surface and the inlet slope, a value of 45.degree.