O-Ring 126x5 NBR 70 ShA GRN

O-Ring 126x5 NBR 70 ShA GRN

O-Ring 126x5 NBR 70 ShA GRN is an elastomeric sealing ring with a nominal inside diameter d1: 126 mm and cross-section d2: 5 mm. It is manufactured from NBR - Nitrile Butadiene Rubber with a nominal hardness of 70 Shore A. The GRN product reference is 126X5.

The key technical identification is:

GRN + 126X5 + NBR + 70 ShA

O-Ring 126x5 NBR 70 ShA GRN - Technical Characteristics

The verified product identification includes:

Brand: GRN

Reference: 126X5

Product type: O-ring / elastomeric sealing ring

Material: NBR

Material name: Nitrile Butadiene Rubber

Nominal hardness: 70 ShA

Hardness scale: Shore A

Inside diameter d1: 126 mm

Cross-section d2: 5 mm

Nominal size: 126x5 mm

Cross-section shape: Circular

For correct identification, the 126x5 dimensions, NBR material and 70 ShA hardness should be considered together.

O-Ring 126x5 Dimensions

The designation 126x5 defines the two principal nominal dimensions of the O-ring:

d1: 126 mm - nominal inside diameter

d2: 5 mm - nominal cross-section diameter

The dimensional designation therefore means:

inside diameter x cross-section

or:

126x5 mm

Based on the nominal geometry, the outside diameter is:

nominal outside diameter: 136 mm

This value is derived geometrically from d1 and d2. It is not a third basic dimension in the O-ring designation.

For product identification and groove design, the primary dimensions remain d1: 126 mm and d2: 5 mm.

O-Ring 126x5 NBR Construction

The O-Ring 126x5 is a closed elastomeric sealing ring with a circular cross-section.

Unlike a radial shaft seal, an O-ring does not incorporate a metal case, garter spring or separately formed sealing lip. The elastomeric ring itself forms the sealing element.

When installed in a correctly designed groove, the circular cross-section is compressed between the mating surfaces. Elastic deformation of the NBR material creates the contact pressure required to establish the seal.

Sealing performance therefore depends not only on the dimensions of the O-ring but also on the geometry of the installation.

How Does the O-Ring 126x5 Work?

The fundamental sealing mechanism of an O-ring is controlled compression of its elastomeric cross-section.

For this specific product, the nominal cross-section is:

d2: 5 mm

After installation in an appropriately designed groove, the cross-section is deformed and the elastomer creates contact pressure against the mating surfaces.

In pressurized systems, differential pressure can additionally displace the O-ring toward the low-pressure side of the groove and affect the contact pressure distribution.

A maximum operating pressure cannot be determined from the designation 126x5 NBR 70 ShA alone. It also depends on installation geometry, clearance, temperature and operating conditions.

NBR Material

The material of this O-ring is identified as:

NBR - Nitrile Butadiene Rubber

NBR is a widely used family of elastomers for technical sealing elements.

Individual NBR compounds can differ in formulation and performance characteristics. Therefore, the generic designation NBR alone is not sufficient to assign an exact operating temperature range, detailed chemical resistance profile or other limiting operating values to this specific product.

Compatibility of the actual compound with the operating medium and conditions should be verified before installation.

What Does 70 ShA Mean?

70 ShA identifies the nominal elastomer hardness on the Shore A scale.

The confirmed material identification for this product is:

NBR 70 ShA

Hardness is an important O-ring parameter because it influences how the elastomer behaves under compression and load.

However, 70 ShA should not be used as the only selection criterion.

Two O-rings with identical 126x5 mm dimensions but different elastomer materials or hardness values are not necessarily technically equivalent.

O-Ring 126x5 vs 126x3.5

O-rings can have the same nominal inside diameter but different cross-sections.

For example:

126x5 - d1: 126 mm, d2: 5 mm

126x3.5 - d1: 126 mm, d2: 3.5 mm

These are two different O-ring sizes.

The difference in cross-section is 1.5 mm, which directly affects groove geometry and the required installation dimensions.

Therefore, O-Ring 126x5 NBR 70 ShA and O-Ring 126x3.5 NBR 70 ShA should be treated as separate products and should not be considered interchangeable based solely on their identical 126 mm inside diameter.

O-Ring 126x5 NBR vs Other Elastomer Materials

The 126x5 mm dimensions do not identify the O-ring material.

O-rings of the same nominal dimensions can be manufactured from different elastomers, including NBR, FKM/FPM, EPDM and VMQ.

Therefore, matching:

d1: 126 mm

and

d2: 5 mm

does not establish complete technical interchangeability.

For example, an:

O-Ring 126x5 NBR 70 ShA

should not automatically be replaced by an:

O-Ring 126x5 EPDM 70 ShA

simply because the nominal dimensions and hardness are the same.

Material compatibility with the operating medium and conditions must also be considered.

Selection and Interchangeability

When selecting an O-Ring 126x5 NBR 70 ShA, verify at least:

• inside diameter d1: 126 mm
• cross-section d2: 5 mm
• material: NBR
• nominal hardness: 70 ShA
• compatibility with the operating medium
• operating temperature
• pressure
• static or dynamic sealing arrangement
• groove geometry
• required O-ring compression
• installation clearance
• condition of the mating surfaces

An alternative O-ring should not be selected solely according to its inside diameter.

The cross-section, elastomer material and hardness must also be considered, together with the actual installation and operating conditions.

Technical Specification

FAQ

What are the dimensions of the O-Ring 126x5 NBR 70 ShA?

The nominal inside diameter d1: 126 mm and the cross-section d2: 5 mm. Its dimensional designation is 126x5.

What does 126x5 mean on an O-ring?

The first value, 126, identifies the nominal inside diameter in millimetres. The second value, 5, identifies the nominal cross-section diameter.

What is the outside diameter of an O-Ring 126x5?

Based on nominal geometry, the outside diameter is 136 mm. The primary identification dimensions remain d1 and d2.

What material is the O-Ring 126x5 made from?

This specific version is manufactured from NBR - Nitrile Butadiene Rubber.

What does 70 ShA mean?

70 ShA specifies a nominal elastomer hardness of 70 on the Shore A scale.

Are O-Rings 126x5 and 126x3.5 interchangeable?

No. Although both have a nominal 126 mm inside diameter, their cross-sections are different: 5 mm and 3.5 mm. They require different installation geometry.

Can an O-Ring 126x5 NBR be replaced by a 126x5 EPDM O-ring?

Not based on dimensions alone. NBR and EPDM are different elastomers, so compatibility with the operating medium and conditions must also be verified.

How should an equivalent O-Ring 126x5 NBR 70 ShA be selected?

Compare d1: 126 mm, d2: 5 mm, NBR material and 70 ShA hardness, then verify the operating medium, temperature, pressure and groove geometry.

AI Overview

GRN O-Ring 126x5 NBR 70 ShA is an elastomeric sealing ring with a nominal inside diameter d1: 126 mm and cross-section d2: 5 mm. It is manufactured from Nitrile Butadiene Rubber (NBR) with a nominal hardness of 70 Shore A. GRN reference: 126X5. Selection requires verification of dimensions, material and operating conditions.