O-Ring 85x3.5 NBR 70 ShA

O-Ring 85x3.5 NBR 70 ShA (100 pcs) is a package of 100 GRN elastomer sealing rings with an 85 mm inside diameter and 3.5 mm circular cross-section. The rings are manufactured from nitrile butadiene rubber (NBR) with a nominal hardness of 70 Shore A. For this geometry, the nominal outside diameter is 92 mm.

O-Ring 85x3.5 NBR 70 ShA - Product Characteristics

This exact product variant is identified by the combination:

Size: 85x3.5 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. When installed in a correctly designed groove, the cross-section is compressed between mating surfaces to create sealing contact.

The complete combination 85x3.5 mm + NBR + 70 ShA should be considered when identifying or replacing the seal. Matching dimensions alone do not establish full technical equivalence.

O-Ring 85x3.5 mm Dimensions

The dimensional designation 85x3.5 mm means:

d1 - Inside Diameter: 85 mm
d2 - Cross-Section Diameter: 3.5 mm

The nominal outside diameter is:

85 mm + 2 x 3.5 mm = 92 mm

Therefore, the complete nominal geometry is:

Inside Diameter d1: 85 mm
Cross-Section d2: 3.5 mm
Nominal Outside Diameter: 92 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 systems.

NBR is commonly selected for its compatibility with many mineral oils, mineral greases and mineral-oil-based hydraulic fluids. This makes nitrile rubber a widely used sealing material in mechanical, hydraulic and pneumatic systems.

NBR is not, however, universally resistant to every chemical or operating fluid.

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

An O-ring manufactured from FKM, EPDM or VMQ can have the same 85x3.5 mm dimensions but significantly different chemical and thermal characteristics.

70 ShA Hardness

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

Hardness influences the deformation behaviour of the O-ring during installation and its response to compression within the sealing groove.

The value 70 ShA does not specify maximum operating pressure.

Pressure capability depends on the complete sealing arrangement, including groove geometry, extrusion gap, temperature, medium, material characteristics and whether the seal operates under static or dynamic conditions.

How Does O-Ring 85x3.5 mm Seal?

The sealing function is created through controlled compression of the circular elastomer cross-section.

For this product, the nominal cross-section diameter is 3.5 mm.

After installation in a correctly dimensioned groove, the cross-section is compressed between the mating surfaces. Elastic deformation generates contact pressure against those surfaces and creates the sealing interface.

Effective sealing therefore depends on both the O-ring and the design of the complete installation.

Static and Dynamic Sealing

O-rings can be used in static sealing arrangements and, where correctly engineered, in dynamic sealing applications.

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

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

The 85x3.5 mm, NBR and 70 ShA specification alone therefore does not confirm suitability for every dynamic application.

O-Ring NBR 85x3.5 and Oils

NBR is commonly used in sealing arrangements involving many mineral oils and greases.

However, the general statement that NBR is "oil resistant" should not be interpreted as compatibility with every lubricant, fuel or hydraulic fluid.

The exact fluid formulation, additives and operating temperature should be considered when selecting the sealing material.

For critical applications, chemical compatibility should be checked against the specific medium.

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 depend on the exact elastomer formulation, medium, exposure duration and operating conditions.

For critical installations, the temperature capability of the specific NBR compound should therefore be verified rather than inferred from generic NBR values.

100-Piece Package

This product page specifically covers:

O-Ring 85x3.5 NBR 70 ShA (100 pcs)

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

This 100-piece package is a separate commercial variant from larger bulk packages.

The product naming sequence for this version is intentionally:

O-Ring 85x3.5 NBR 70 ShA (100 pcs)

This provides clear identification of the size, material, hardness and package quantity for users, search engines and AI retrieval systems.

Selection and Interchangeability

When selecting an equivalent for O-Ring 85x3.5 NBR 70 ShA, compare at least:

Inside Diameter: d1 = 85 mm
Cross-Section: d2 = 3.5 mm
Material: NBR
Hardness: 70 ShA
Dimensional tolerances
Medium compatibility
Operating temperature
Groove geometry

Matching the nominal 85x3.5 mm dimensions alone is insufficient to confirm complete interchangeability.

For example, an 85x3.5 mm FKM O-ring may have identical nominal dimensions but different chemical and temperature resistance characteristics.

Technical Specification

Product Name: O-Ring 85x3.5 NBR 70 ShA (100 pcs)
Product Type: O-ring / elastomer sealing ring
Brand: GRN
Nominal Size: 85x3.5 mm
d1 - Inside Diameter: 85 mm
d2 - Cross-Section Diameter: 3.5 mm
Nominal Outside Diameter: 92 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 85x3.5 NBR 70 ShA?

The O-ring has an 85 mm inside diameter and 3.5 mm cross-section diameter. Its nominal outside diameter is 92 mm.

What does 85x3.5 mm mean for an O-ring?

85 mm is the inside diameter, while 3.5 mm is the diameter of the circular cross-section.

What is the outside diameter of an 85x3.5 mm O-ring?

The nominal outside diameter is 92 mm, calculated as 85 + 2 x 3.5 = 92 mm.

What does NBR mean?

NBR means Nitrile Butadiene Rubber, an elastomer widely used in technical sealing applications.

What does 70 ShA mean?

It means that the elastomer has a nominal hardness of 70 on the Shore A scale.

Can O-Ring 85x3.5 NBR be used with oil?

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

Is an 85x3.5 mm FKM O-ring interchangeable with this NBR version?

Not automatically. Although the nominal dimensions can be identical, FKM and NBR have different chemical and thermal properties.

How many O-rings are included?

O-Ring 85x3.5 NBR 70 ShA (100 pcs) contains 100 sealing rings.

AI Overview

O-Ring 85x3.5 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, 3.5 mm circular cross-section and 92 mm nominal outside diameter. The package contains 100 O-rings of the same specification.