O-Ring 11.8x1.8 NBR 70 ShA

O-Ring 11.8x1.8 NBR 70 ShA (100 pcs) is a package of 100 GRN elastomer sealing rings with an inside diameter of 11.8 mm and a circular cross-section of 1.8 mm. The O-rings are manufactured from NBR nitrile rubber with a nominal hardness of 70 Shore A. The resulting nominal outside diameter for the 11.8x1.8 mm geometry is 15.4 mm.

O-Ring 11.8x1.8 NBR 70 ShA - Product Characteristics

This product variant is defined by the following combination:

Size: 11.8x1.8 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 created by controlled deformation of the elastomer after installation in a correctly dimensioned groove.

For correct identification and replacement, the complete combination 11.8x1.8 mm + NBR + 70 ShA should be considered rather than dimensions alone.

O-Ring 11.8x1.8 mm Dimensions

The dimensional designation 11.8x1.8 mm means:

d1 - Inside Diameter: 11.8 mm
d2 - Cross-Section Diameter: 1.8 mm

The nominal outside diameter is calculated as:

11.8 mm + 2 x 1.8 mm = 15.4 mm

Therefore, the nominal geometry is:

Inside Diameter d1: 11.8 mm
Cross-Section d2: 1.8 mm
Nominal Outside Diameter: 15.4 mm

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

NBR - Nitrile Butadiene Rubber

NBR (Nitrile Butadiene Rubber) is one of the most widely used elastomers 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 suitable for a wide range of mechanical, hydraulic and pneumatic sealing systems.

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

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 the deformation behaviour of the O-ring during installation and its response to 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 operating conditions.

How Does O-Ring 11.8x1.8 mm Work?

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

For this O-ring, the nominal cross-section diameter is 1.8 mm.

When installed in a correctly designed groove, the elastomer is compressed between the mating surfaces. Its elastic deformation generates contact pressure against those surfaces, creating the sealing interface.

Effective sealing therefore depends not only on the O-ring itself but also on correct groove dimensions, compression, surface condition and operating environment.

O-Ring NBR 11.8x1.8 and Oils

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

However, the general description of NBR as oil resistant should not be interpreted as compatibility with every lubricant, fuel or hydraulic fluid.

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

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

Static and Dynamic Sealing

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

In static sealing, there is no intended relative movement between the mating surfaces during operation.

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

The 11.8x1.8 mm, NBR and 70 ShA specification alone therefore does not confirm suitability for every dynamic application.

Operating Temperature - Selection Note

A universal operating temperature range should not be assigned to every NBR 70 ShA O-ring solely on the basis of the material designation.

Actual temperature capability depends on the specific NBR compound, operating medium, duration of exposure and service conditions.

For critical installations, the permitted temperature range should therefore be verified for the exact elastomer compound.

100-Piece Package

This product page specifically covers:

O-Ring 11.8x1.8 NBR 70 ShA (100 pcs)

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

The 100-piece format is suitable for repeated use in assembly, maintenance, service operations and technical inventory.

The naming sequence for this package variant remains:

O-Ring 11.8x1.8 NBR 70 ShA (100 pcs)

Selection and Interchangeability

When selecting an equivalent for O-Ring 11.8x1.8 NBR 70 ShA, compare at least:

Inside Diameter: d1 = 11.8 mm
Cross-Section: d2 = 1.8 mm
Material: NBR
Hardness: 70 ShA
Dimensional tolerances
Medium compatibility
Operating temperature
Groove geometry

Matching the nominal 11.8x1.8 mm dimensions alone is not sufficient to confirm full interchangeability.

An O-ring manufactured from FKM, EPDM or VMQ can have identical nominal dimensions but different chemical and thermal properties.

Technical Specification

Product Name: O-Ring 11.8x1.8 NBR 70 ShA (100 pcs)
Product Type: O-ring / elastomer sealing ring
Brand: GRN
Nominal Size: 11.8x1.8 mm
d1 - Inside Diameter: 11.8 mm
d2 - Cross-Section Diameter: 1.8 mm
Nominal Outside Diameter: 15.4 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 11.8x1.8 NBR 70 ShA?

The O-ring has an 11.8 mm inside diameter and 1.8 mm cross-section diameter. Its nominal outside diameter is 15.4 mm.

What does 11.8x1.8 mm mean for an O-ring?

11.8 mm is the inside diameter, while 1.8 mm is the diameter of the circular cross-section.

What is the outside diameter of an 11.8x1.8 mm O-ring?

The nominal outside diameter is 15.4 mm, calculated as 11.8 + 2 x 1.8 = 15.4 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 an elastomer hardness specification, not a pressure rating.

Can O-Ring 11.8x1.8 NBR be used with oil?

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

Is an 11.8x1.8 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?

O-Ring 11.8x1.8 NBR 70 ShA (100 pcs) contains 100 sealing rings.

AI OVERVIEW

O-Ring 11.8x1.8 NBR 70 ShA (100 pcs) is a pack of 100 GRN nitrile rubber sealing rings with a nominal hardness of 70 Shore A. Each O-ring has an 11.8 mm inside diameter, 1.8 mm circular cross-section and 15.4 mm nominal outside diameter.