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HERCULES URETHANE BACKUP Ring 90A DUROMETER

Description & Features

Rated at 90A durometer, this urethane backup ring is suited for hydraulic sealing applications where extrusion resistance is a priority. The 90A hardness rating makes it effective in moderate-to-high pressure environments, helping to support primary seals and prevent deformation under load. Urethane construction offers a practical balance of flexibility and wear resistance for dynamic and static sealing use.

The Hercules Urethane Backup Ring 90A Durometer is a Hercules Sealing Products component, a manufacturer recognized in industrial sealing for consistent material quality and dimensional accuracy. Backup rings of this type are commonly used in hydraulic cylinders, actuators, and fluid power assemblies where seal integrity under pressure is essential.

SKU: 575-250

Supplier Part Number (MPN): 575-250

Alternate Part Numbers: C1BU97

Specifications

Alternate Part Numbers Alternate Part Number C1BU97	Brand Hercules Sealing Products	Brand Hercules Sealing Products	Pack Size 1.00	UOM EA	Supplier Part Number 575-250	Product Weight 0.01 lbs

Product Questions & Answers (1)

Question by: Dwight M on Dec 20, 2025, 9:07 PM

backup ring says 90A durometer -- is that gonna hold up in a high-pressure cylinder or is it more of a light-duty thing

Answer by: Customer Support on Dec 22, 2025, 1:33 PM

90A durometer puts this squarely in the firm range for urethane, which is what you want when a backup ring is doing its job behind a primary seal under pressure. Softer materials tend to extrude into clearance gaps when things get loaded up. Urethane at this hardness resists that kind of deformation better than rubber-based options, so it's a reasonable choice for hydraulic cylinder applications where pressure is a real concern.