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HERCULES URETHANE BACKUP Ring 90A DUROMETER

Description & Features

The Hercules Sealing Products 90A durometer Urethane Backup Ring provides reliable sealing performance in hydraulic applications.

This HERCULES URETHANE BACKUP Ring 90A DUROMETER is designed to prevent o-ring extrusion in high-pressure environments, ensuring system integrity and longevity.

SKU: 575-318

Supplier Part Number (MPN): 575-318

Alternate Part Numbers: C1BV29, MI-01811171, MINO-00407Q30940

Specifications

Alternate Part Numbers Alternate Part Number C1BV29, Alternate Part Number MI-01811171, Alternate Part Number MINO-00407Q30940	Brand Hercules Sealing Products	Brand Hercules Sealing Products	Pack Size 1.00	UOM EA	Supplier Part Number 575-318	Product Weight 0.01 lbs

Product Questions & Answers (1)

Question by: Tony C on Oct 24, 2025, 8:23 AM

backup ring rated 90 durometer -- is that pretty stiff compared to what usually comes stock on most cylinders?

Answer by: Customer Support on Oct 25, 2025, 9:53 PM

Urethane at 90A durometer sits on the firmer end of the scale for backup rings. Stock seals often run softer, so swapping in a 90A urethane piece gives you better resistance to extrusion under pressure. For most hydraulic cylinder applications where fluid wants to push the primary seal out of its groove, that extra firmness is exactly what keeps the assembly holding together over time.