Solid riders or wear rings, AAVOLYN Type 450, are required where the ring groove on the
piston travels out into the valve area or cylinder counterbore. The solid, stretch on ring is
designed to stretch over the piston diameter and then fit tightly on the ring groove. Proper
strain and memory considerations are important to ensure that the solid ring remains tightly
on the piston during operating temperatures and pressures. Pressure relief designs are
available in high temperature applications where riders have a tendency to come loose on the
piston in service. This allows gas, trapped under the ring, to bleed away, thus eliminating
rapid wear of the ring and possible breakage.
