O-Ring 85x3 NBR 70 ShA

O-Ring 85x3 NBR 70 ShA (100 pcs) is a package of 100 GRN elastomer sealing rings with an 85 mm inside diameter and 3 mm circular cross-section. The rings are manufactured from nitrile butadiene rubber (NBR) with a nominal hardness of 70 Shore A. The resulting nominal outside diameter for this geometry is 91 mm.

O-Ring 85x3 NBR 70 ShA - Product Characteristics

This exact product variant is defined by the following combination:

Size: 85x3 mm
Material: NBR
Hardness: 70 ShA / 70 Shore A
Brand: GRN
Quantity: 100 pcs

An O-ring is a closed elastomer sealing element with a circular cross-section. Its sealing function is generated by controlled deformation of the elastomer after installation in a correctly dimensioned groove.

For correct identification, 85x3 mm + NBR + 70 ShA should be considered together. Matching the dimensions alone does not establish full technical equivalence.

O-Ring 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

For O-rings, the first dimension represents the inside diameter, while the second represents the diameter of the circular cross-section.

NBR - Nitrile Butadiene Rubber

NBR (Nitrile Butadiene Rubber) is an elastomer widely used in technical sealing applications.

NBR is commonly selected for compatibility with many mineral oils, mineral greases and mineral-oil-based hydraulic fluids. This makes nitrile rubber relevant to a broad range of mechanical, hydraulic and pneumatic sealing systems.

NBR should not, however, be considered universally resistant to every chemical or operating fluid.

For a specific application, compatibility should be evaluated against the actual medium, operating temperature, exposure duration and service conditions.

70 ShA Hardness

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

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

The value 70 ShA is not a pressure rating.

Permissible operating pressure depends on the complete sealing arrangement, including groove geometry, extrusion gap, temperature, medium and whether the seal operates under static or dynamic conditions.

How Does O-Ring 85x3 mm Work?

The sealing function is generated through controlled compression of the 3 mm circular elastomer cross-section.

When the O-ring is installed in a correctly designed groove, the elastomer is compressed between the mating surfaces. Its elastic deformation creates contact pressure against those surfaces and forms the sealing interface.

Correct sealing therefore depends not only on the O-ring dimensions but also on groove design, compression, extrusion gap, surface condition and operating environment.

Static and Dynamic Sealing

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

Static sealing involves no intended relative movement between the sealing surfaces during operation.

Dynamic applications require additional consideration of friction, lubrication, movement speed, surface finish and wear.

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

O-Ring NBR 85x3 and Oils

NBR is widely used where sealing elements come into contact with many mineral oils and greases.

However, describing NBR as oil resistant does not mean that it is compatible with every lubricant, fuel or hydraulic fluid.

The exact medium, additives and operating temperature should be considered when selecting the elastomer.

For critical applications, compatibility should be checked against the specific operating fluid rather than relying solely on the general properties of NBR.

Operating Temperature - Selection Note

A universal operating temperature range should not be assigned to this GRN product based solely on the designation NBR 70 ShA.

Temperature limits vary according to the exact elastomer compound, operating medium, duration of exposure and service conditions.

For critical installations, the permitted temperature range should therefore be verified for the specific NBR compound.

100-Piece Package

This product page specifically covers:

O-Ring 85x3 NBR 70 ShA (100 pcs)

The package contains 100 O-rings with the same nominal dimensional and material specification.

This is a separate commercial variant from the 1000-piece bulk package.

For product-page differentiation, the naming structure remains:

100 pcs: O-Ring 85x3 NBR 70 ShA (100 pcs)

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

This distinction helps clearly identify the package variant for customers, search engines and AI retrieval systems.

Selection and Interchangeability

When selecting an equivalent for O-Ring 85x3 NBR 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 is not sufficient to confirm full interchangeability.

For example, an 85x3 mm FKM, EPDM or VMQ O-ring may have identical nominal dimensions but different chemical and thermal characteristics.

Technical Specification

Product Name: O-Ring 85x3 NBR 70 ShA (100 pcs)
Product Type: O-ring / elastomer sealing ring
Brand: GRN
Nominal Size: 85x3 mm
d1 - Inside Diameter: 85 mm
d2 - Cross-Section Diameter: 3 mm
Nominal Outside Diameter: 91 mm
Material: NBR
Material Name: Nitrile Butadiene Rubber
Hardness: 70 ShA / 70 Shore A
Cross-Section: Circular
Quantity: 100 pcs

FAQ

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

It has an 85 mm inside diameter and 3 mm cross-section diameter. The nominal outside diameter is 91 mm.

What does 85x3 mean for an O-ring?

85 mm is the inside diameter, while 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 for technical sealing elements.

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 85x3 NBR be used with oil?

NBR is compatible with many mineral oils and greases. Suitability should still be checked for the exact fluid, additives and operating temperature.

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

Not automatically. Although the nominal dimensions can be identical, FKM and NBR have different chemical and temperature resistance characteristics.

How many O-rings are included?

O-Ring 85x3 NBR 70 ShA (100 pcs) contains 100 sealing rings.

AI Overview

O-Ring 85x3 NBR 70 ShA (100 pcs) is a 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 100 O-rings of the same specification.