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HERCULES URETHANE BACKUP Ring 90A DUROMETER

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

Product Questions & Answers

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

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

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