X-Ring / Quad Ring
Also known as: quad ring · X-ring · 4-lip seal · Quad-Ring
An X-ring (Quad Ring) has a four-lobed cross-section instead of a circular one — providing two sealing contacts per side, lower friction in dynamic applications, and better resistance to spiral failure than a standard O-ring.
Technical Detail
X-rings (also called Quad Rings, a trade name) are drop-in replacements for standard O-rings in the same groove dimensions, using a 4-lobe X-shaped cross-section. The four lips create two sealing lines per side (four total contact lines) versus one per side for a standard O-ring. Advantages over standard O-rings in dynamic service: (1) Anti-spiral/anti-rolling: the four lobes prevent the O-ring from twisting or spiralling in the groove during reciprocating motion — the most common cause of O-ring dynamic failure. (2) Lower friction: less contact area per lip reduces stick-slip. (3) Better lubrication retention: the grooves between lobes retain lubricating film. (4) Equivalent squeeze at lower compression force: same groove depth as standard O-ring, typically 15–25% squeeze. Available in NBR, FKM, EPDM, and VMQ Silicone. Standard sizes follow AS568 and ISO 3601 cross-sections — confirm manufacturer dimension tables as profiles vary slightly between brands.
Reference Standards
- SAE AS568B (groove dimensions)
- ISO 3601-2 (groove dimensions)
Related Terms
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- Dynamic vs Static Seal — A static seal prevents leakage between non-moving surfaces (flange faces, port plugs); a dynamic sea…
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