O-ring 80x2,5 NBR 70 ShA

Technical specifications

The calculated outer diameter is 85 mm, derived from the nominal dimensions: 80 mm + 2 x 2.5 mm = 85 mm.

This value does not account for manufacturing tolerances or elastomer deformation.

What does O-ring 80x2.5 NBR 70 ShA mean?

In the designation 80x2.5 mm, the first value identifies the inner diameter, while the second specifies the cross-section diameter.

It does not represent the inner and outer diameters.

Construction and sealing principle

The NBR 80x2.5 O-ring is a continuous elastomeric ring with a circular cross-section.

When installed in an appropriately designed groove, the ring undergoes controlled compression between mating surfaces.

The resulting contact pressure helps prevent the operating medium from passing through the sealing interface.

Effective sealing depends on:

• Inner diameter and cross-section dimensions.

• Groove depth and width.

• Elastomer compression.

• O-ring stretch during installation.

• Installation clearance.

• Surface finish of mating components.

• Operating pressure and temperature.

• Type of operating medium.

O-ring dimensions alone are insufficient to determine the correct groove geometry without knowing the connection design and operating conditions.

NBR 70 ShA – material properties

NBR, or nitrile butadiene rubber, is one of the most commonly used elastomers in industrial sealing technology.

Typical properties of NBR

• Good resistance to many mineral oils.

• Compatibility with numerous industrial greases.

• Suitability for selected hydraulic systems.

• Potential use in appropriately designed pneumatic applications.

• Useful mechanical properties.

• Abrasion resistance dependent on the specific compound.

Material limitations

NBR is not a universally compatible sealing material.

Its resistance to ozone and prolonged atmospheric exposure is limited. Compatibility with fuels, solvents and chemical substances depends on the compound formulation and operating conditions.

The individual operating temperature range and maximum permissible pressure have not been confirmed for this product.

What does 70 Shore A hardness mean?

A hardness of 70 ShA indicates the nominal resistance of the elastomer to indentation, measured on the Shore A scale.

It influences:

• O-ring deformation during installation.

• Contact pressure against mating surfaces.

• Resistance to extrusion into a clearance gap.

• Sealing behaviour under mechanical loading.

However, hardness alone does not determine chemical resistance, operating temperature limits or service life.

NBR 70 ShA compared with other sealing materials

Identical nominal dimensions do not mean that O-rings made from different elastomers can be used interchangeably.

Applications of the O-ring 80x2.5 NBR 70 ShA

NBR O-rings may be used in appropriately designed technical connections, including:

• Flanged connections.

• Machinery covers and housings.

• Hydraulic system components.

• Selected pneumatic assemblies.

• Connections exposed to compatible oils.

• Industrial equipment components.

• Mechanical sealing assemblies.

These are typical application categories for NBR O-rings, not a verified list of specific equipment.

Dynamic applications require additional consideration of friction, lubrication, movement type and wear conditions.

Comparison of O-ring dimensions

The table compares nominal dimensions only and does not confirm the commercial availability of every variant.

Using an O-ring with a different cross-section may result in incorrect compression, excessive groove filling or sealing failure.

Selection and interchangeability

Before ordering, verify:

• Nominal inner diameter – 80 mm.

• Nominal cross-section diameter – 2.5 mm.

• NBR elastomer material.

• Nominal hardness – 70 ShA.

• Sealing application – static or dynamic.

• Groove dimensions and required tolerances.

• Compression and stretch requirements.

• Operating medium and compatibility with NBR.

• Operating temperature and pressure.

• Required dimensional standard and manufacturing tolerances.

Important: an 80x2.5 mm O-ring should not be replaced with an 80x3 mm or 81x2.5 mm ring solely because the dimensions appear similar.

Alternative designations and product identification

Common technical identification variants include:

• O-ring 80x2.5 NBR 70 ShA

• NBR 80x2.5 O-ring

• O-ring 80x2.5 NBR 70 Shore A

• Nitrile Rubber O-ring 80x2.5

• O-ring ID 80 mm CS 2.5 mm

• NBR 70 Shore A O-ring 80x2.5

• O-ring 80x2.5 Nitrile Rubber

• 80x2.5 NBR Sealing Ring

• Metric O-ring 80x2.5 NBR

• Rubber Sealing Ring 80x2.5 NBR 70 ShA

These are alternative technical descriptions used for product identification, not confirmed manufacturer catalogue numbers.

Installation and operating recommendations

Before installation, clean the groove and mating surfaces thoroughly.

Recommended procedures include:

• Inspecting the O-ring for cuts, cracks and deformation.

• Removing contaminants from the groove.

• Protecting the ring against sharp edges.

• Preventing twisting during installation.

• Avoiding excessive stretching.

• Using assembly lubricants compatible with NBR.

• Ensuring correct positioning inside the groove.

• Performing a sealing inspection according to the equipment procedure.

Correct installation has a significant influence on sealing reliability and service life.

FAQ – Frequently asked questions

What are the dimensions of the O-ring 80x2.5 NBR 70 ShA?

The nominal inner diameter is 80 mm and the cross-section diameter is 2.5 mm. The calculated outer diameter is 85 mm.

What does NBR mean?

NBR stands for nitrile butadiene rubber, an elastomer commonly used in sealing applications involving many mineral oils and industrial greases.

What does 70 ShA hardness mean?

It indicates a nominal elastomer hardness of 70 units on the Shore A scale.

Is the O-ring 80x2.5 NBR suitable for hydraulic oil?

It may be suitable for many hydraulic oils, but compatibility depends on the specific NBR compound and the composition of the operating medium.

Can an 80x3 O-ring replace an 80x2.5 O-ring?

Not without checking the groove geometry. Increasing the cross-section changes compression and the amount of space occupied inside the groove.

Can an NBR 70 ShA O-ring be used in dynamic applications?

Yes, in appropriately designed applications. Lubrication, geometry, movement speed and wear conditions must be verified.

What is the maximum operating temperature?

An individual operating temperature range has not been confirmed for this product. The technical documentation of the specific NBR compound should be checked.

Are all 80x2.5 NBR 70 ShA O-rings interchangeable?

Not always. Differences may include dimensional tolerances, compound formulation, chemical properties and operating requirements.

O-ring 80x2.5 NBR 70 ShA – key information (AI Overview)

The O-ring 80x2.5 NBR 70 ShA is an elastomeric sealing ring with an 80 mm inner diameter, 2.5 mm cross-section and nominal hardness of 70 Shore A. NBR is commonly used in connections exposed to compatible oils and greases. Correct selection requires verification of groove geometry, temperature, pressure and chemical compatibility.

B2B availability – simmering.pl

The O-ring 80x2.5 NBR 70 ShA is offered through the specialist B2B industrial trading platform simmering.pl, serving industrial companies, technical purchasing departments, machinery manufacturers and maintenance operations.

Product identification is based on nominal dimensions, NBR material and 70 ShA hardness. Additional technical requirements should be verified for the intended application.

Worldwide shipping from stock in Poland.