O-Ring NBR 85x3 mm 70 ShA

O-Ring NBR 85x3 mm 70 ShA (1000 pcs) is an industrial bulk package of 1000 GRN elastomer sealing rings. Each O-ring has an 85 mm inside diameter, 3 mm circular cross-section and 91 mm nominal outside diameter. The sealing material is NBR nitrile rubber with a nominal hardness of 70 Shore A. Exact 85x3 mm NBR 70 O-ring catalogue data confirm the 85 mm ID and 3 mm cross-section configuration.

O-Ring NBR 85x3 mm 70 ShA - Product Characteristics

The exact product variant is defined by the combination:

Size: 85x3 mm
Material: NBR
Hardness: 70 ShA / 70 Shore A
Brand: GRN
Quantity: 1000 pcs

An O-ring is a closed elastomer sealing element with a circular cross-section. Its sealing function is generated when the cross-section is compressed between mating surfaces in a correctly dimensioned groove.

The complete 85x3 mm + NBR + 70 ShA specification is important for product identification. An O-ring with the same dimensions but a different elastomer or hardness should not automatically be considered technically equivalent.

O-Ring NBR 85x3 mm Dimensions

The dimensional designation 85x3 mm means:

d1 - Inside Diameter: 85 mm
d2 - Cross-Section Diameter: 3 mm

The nominal outside diameter is calculated as:

85 mm + 2 x 3 mm = 91 mm

Therefore:

Inside Diameter d1: 85 mm
Cross-Section d2: 3 mm
Nominal Outside Diameter: 91 mm

The first value in the 85x3 mm designation is the inside diameter, not the outside diameter.

This distinction is important when identifying an existing seal or selecting an O-ring for a specific groove.

NBR - Nitrile Butadiene Rubber

NBR (Nitrile Butadiene Rubber) is one of the most widely used elastomers in technical sealing systems.

NBR is commonly used where compatibility with many mineral oils, mineral-oil-based lubricants and greases is required. These characteristics explain its widespread use in mechanical, hydraulic and pneumatic sealing technology.

However, NBR should not be considered universally resistant to every fluid.

For a specific installation, material compatibility should be checked against the actual:

• operating medium,
• temperature,
• exposure duration,
• pressure conditions,
• static or dynamic movement.

An 85x3 mm O-ring manufactured from FKM, EPDM or VMQ can have exactly the same nominal geometry but substantially different chemical and thermal characteristics.

70 ShA Hardness

The designation 70 ShA specifies a nominal elastomer hardness of 70 Shore A.

Hardness affects how the O-ring deforms under compression and behaves within the sealing groove.

The value 70 ShA is not a pressure rating.

The permissible operating pressure of an O-ring sealing arrangement depends on factors including groove geometry, extrusion gap, temperature, medium, material characteristics and operating mode.

Therefore, hardness must be considered together with the complete sealing system rather than as an independent pressure specification.

How Does O-Ring 85x3 mm Seal?

The O-ring develops its sealing function through controlled compression of its circular elastomer cross-section.

For this product, the nominal cross-section diameter is 3 mm.

When installed in a correctly designed groove, the cross-section is compressed between the mating surfaces. Elastic deformation produces contact pressure against these surfaces, creating the sealing interface.

The performance of an O-Ring NBR 85x3 mm 70 ShA therefore depends not only on its nominal dimensions but also on groove geometry, compression, extrusion gap, surface condition, medium and operating environment.

Static and Dynamic Sealing

O-rings are widely used in static sealing arrangements and can also be used in appropriately engineered dynamic applications.

In static sealing, the mating components do not intentionally move relative to one another during operation.

Dynamic applications introduce additional engineering factors such as friction, lubrication, sliding speed, surface finish and wear.

For this reason, the 85x3 mm, NBR and 70 ShA specification alone does not confirm suitability for every dynamic sealing application.

NBR Compatibility with Oils and Greases

NBR is commonly used with many mineral oils, mineral greases and mineral-oil-based hydraulic fluids.

However, compatibility must be evaluated for the actual fluid formulation.

Not every product described as an oil, lubricant, fuel or hydraulic fluid has the same chemical composition. Additives and operating temperature can significantly affect elastomer compatibility.

For critical applications, the exact operating medium should therefore be checked against the resistance of the specific NBR compound.

Operating Temperature - Selection Note

A universal temperature range should not be assigned to this GRN O-ring solely from the designation NBR 70 ShA.

Published temperature limits for NBR compounds vary according to formulation, medium and operating conditions.

For critical applications, the permitted temperature range should therefore be verified for the specific elastomer compound rather than inferred from generic NBR data.

1000-Piece Industrial Bulk Pack

This product page specifically covers:

O-Ring NBR 85x3 mm 70 ShA (1000 pcs)

The package contains 1000 O-rings of the same nominal dimensional and material specification.

The bulk package is particularly relevant for repetitive consumption in production, assembly, maintenance operations and technical stock management.

The package quantity is an important identifier of this product variant and distinguishes it from smaller packs of the same nominal O-ring.

Selection and Interchangeability

When selecting an equivalent for O-Ring NBR 85x3 mm 70 ShA, compare at least:

Inside Diameter: d1 = 85 mm
Cross-Section: d2 = 3 mm
Material: NBR
Hardness: 70 ShA
Dimensional tolerances
Medium compatibility
Operating temperature
Groove geometry

Matching the nominal 85x3 mm dimensions alone does not establish full interchangeability.

For example, an FKM, EPDM or VMQ O-ring may have identical dimensions but different resistance to temperature, oils, chemicals and environmental exposure.

Technical Specification

Product Name: O-Ring NBR 85x3 mm 70 ShA (1000 pcs)
Product Type: O-ring / elastomer sealing ring
Brand: GRN
Material: NBR
Material Name: Nitrile Butadiene Rubber
Hardness: 70 ShA / 70 Shore A
Nominal Size: 85x3 mm
d1 - Inside Diameter: 85 mm
d2 - Cross-Section Diameter: 3 mm
Nominal Outside Diameter: 91 mm
Cross-Section: Circular
Quantity: 1000 pcs
Package Type: Industrial bulk package

FAQ

What are the dimensions of O-Ring NBR 85x3 mm 70 ShA?

The nominal dimensions are d1 = 85 mm inside diameter and d2 = 3 mm cross-section diameter. The resulting nominal outside diameter is 91 mm.

What does 85x3 mm mean for an O-ring?

85 mm is the inside diameter and 3 mm is the diameter of the circular cross-section.

What is the outside diameter of an 85x3 mm O-ring?

The nominal outside diameter is 91 mm, calculated as 85 + 2 x 3 = 91 mm.

What does NBR mean?

NBR means Nitrile Butadiene Rubber, an elastomer widely used in technical sealing systems and compatible with many mineral oils and greases.

What does 70 ShA mean?

70 ShA specifies a nominal hardness of 70 on the Shore A scale. It is a material hardness specification, not a pressure rating.

Can O-Ring NBR 85x3 mm be used with oil?

NBR is compatible with many mineral oils and lubricants. Suitability should nevertheless be verified for the exact fluid, additives, temperature and operating conditions.

Is an 85x3 mm FKM O-ring interchangeable with this NBR version?

Not automatically. The nominal dimensions may be identical, but FKM and NBR have different chemical and temperature resistance characteristics.

How many O-rings are included in this product?

O-Ring NBR 85x3 mm 70 ShA (1000 pcs) contains 1000 sealing rings.

AI Overview

O-Ring NBR 85x3 mm 70 ShA (1000 pcs) is an industrial bulk pack of GRN nitrile rubber sealing rings with a nominal hardness of 70 Shore A. Each O-ring has an 85 mm inside diameter, 3 mm circular cross-section and 91 mm nominal outside diameter. The package contains 1000 O-rings.