Back-Up Rings

Back-up rings are firm supporting rings placed beside softer seals to bridge a clearance gap. They reduce extrusion and nibbling of an O-ring or lip seal when pressure pushes the elastomer towards the gap, and may be installed on one or both sides depending on pressure direction.

Key facts

Family: O-Rings & Static Seals
Common types: Solid ring, Scarf-cut ring, Spiral ring, Split ring, Contoured ring
Materials: Virgin PTFE, Filled PTFE, POM, Polyamide, Hard NBR
Used in: Hydraulic valves, Cylinder end caps, Fluid pumps, High-pressure couplings, Manifolds

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Types

Solid ring
Scarf-cut ring
Spiral ring
Split ring
Contoured ring

Materials

Applications

Hydraulic valves
Cylinder end caps
Fluid pumps
High-pressure couplings
Manifolds

What to send for a quote

matching seal size
groove width
cut style
pressure direction
support material

Questions about back-up rings

What should I send to identify back-up rings?

Send matching seal size, groove width, cut style, pressure direction, support material. State whether one or two rings are used and show their position relative to the O-ring in the assembled groove. A clear photograph, drawing or readable reference can resolve details that dimensions alone do not show.

How should I select back-up rings?

Base material and arrangement on extrusion gap, pressure direction, temperature, fluid and whether the groove permits a solid ring. Confirm the mating parts and operating environment before ordering, since an apparently similar size can use a different profile, material or internal arrangement.

Last updated: 2026-10-08