GRN® 11x21x7 NBR AO/TC Double-Lip Rotary Shaft Seal

GRN® 11x21x7 NBR AO/TC Double-Lip Rotary Shaft Seal

GRN® 11x21x7 NBR AO/TC is a double-lip rotary shaft seal / radial shaft seal / oil seal with nominal dimensions of 11x21x7 mm. It is manufactured from NBR - Nitrile Butadiene Rubber. The AO/TC design combines a spring-loaded primary dynamic sealing lip with an additional auxiliary dust lip.

The key technical identification is:

GRN® + 11x21x7 mm + NBR + AO/TC

GRN® 11x21x7 NBR AO/TC - Technical Characteristics

Brand: GRN®

Product type: Rotary Shaft Seal / Radial Shaft Seal / Oil Seal

Design: AO/TC

Configuration: Double lip

Material: NBR

Material name: Nitrile Butadiene Rubber

Dimensions: 11x21x7 mm

Shaft diameter d: 11 mm

Outside diameter D: 21 mm

Seal width B: 7 mm

Primary sealing lip: Yes

Garter spring: Yes

Additional dust lip: Yes

The complete dimensions, elastomer material and sealing-lip configuration should be considered together when identifying the exact seal.

GRN® 11x21x7 Oil Seal Dimensions

Nominal dimensions:

d = 11 mm - nominal shaft diameter

D = 21 mm - nominal outside diameter / housing bore diameter

B = 7 mm - axial seal width

Complete dimensions:

11x21x7 mm

The seal is dimensionally specified for a nominal 11 mm shaft and 21 mm housing bore, with an axial width of 7 mm.

All three dimensions should be retained when selecting a replacement.

AO/TC Double-Lip Seal Design

The AO/TC configuration incorporates:

a primary dynamic sealing lip

a garter spring acting on the primary sealing lip

an additional auxiliary dust lip

The primary lip operates dynamically against the rotating shaft surface and performs the principal sealing function.

The auxiliary lip provides an additional external barrier against dust and contamination approaching the primary sealing area.

Spring-Loaded Primary Sealing Lip

The primary sealing lip operates against the nominal:

d = 11 mm shaft

A circumferential garter spring helps maintain radial contact between the primary sealing edge and the rotating shaft surface.

The spring acts on the primary dynamic sealing lip. The additional dust lip should not be interpreted as a second identical spring-loaded sealing lip.

Additional Auxiliary Dust Lip

The AO/TC design incorporates an additional auxiliary dust lip.

Its primary function is to provide an additional protective barrier between the external environment and the main sealing area.

This is one of the principal construction differences between the AO/TC double-lip design and an A/SC single-lip design.

NBR - Nitrile Butadiene Rubber

The sealing material is:

NBR - Nitrile Butadiene Rubber

Material forms an integral part of the exact product identification:

11x21x7 + NBR + AO/TC

A seal with the same 11x21x7 mm dimensions but manufactured from FKM/FPM, silicone or another elastomer represents a different material variant.

The exact NBR compound used for this GRN® product has not been confirmed. Therefore, an exact hardness, fixed operating temperature range, maximum pressure or maximum shaft speed should not be assigned solely from generic NBR properties.

How Does the GRN® 11x21x7 Rotary Shaft Seal Work?

A rotary shaft seal operates between a:

rotating shaft

and a

stationary housing

For this variant:

Nominal shaft diameter: 11 mm

Nominal housing bore diameter: 21 mm

Seal width: 7 mm

The spring-loaded primary sealing lip operates dynamically against the shaft surface, while the additional AO/TC lip provides an external protective barrier.

Actual sealing performance also depends on shaft surface quality, runout, alignment, rotational speed, temperature, sealed medium, lubrication and installation conditions.

GRN® 11x21x7 AO/TC vs A/SC

Seals with identical nominal dimensions can have different lip configurations.

AO/TC - double lip:

Spring-loaded primary sealing lip
Additional auxiliary dust lip

A/SC - single lip:

Spring-loaded primary sealing lip
No additional dust lip

Therefore:

11x21x7 NBR AO/TC ≠ 11x21x7 NBR A/SC

in terms of sealing-lip construction.

Identical dimensions and NBR material alone do not establish complete technical interchangeability.

GRN® 11x21x7 vs 10x21x7

These two sizes share:

D = 21 mm

B = 7 mm

but differ in shaft diameter:

11x21x7: d = 11 mm

10x21x7: d = 10 mm

The nominal shaft diameter differs by 1 mm.

Therefore, 10x21x7 and 11x21x7 are not dimensionally interchangeable, despite having the same outside diameter and width.

Why Is the 11x21x7 Dimension Important?

Each value identifies a different installation dimension:

11 mm - nominal shaft diameter

21 mm - nominal housing bore diameter

7 mm - axial seal width

A similar-looking seal with a 10 mm or 12 mm inside diameter is a different dimensional variant.

The complete 11x21x7 mm dimension should therefore be retained during identification and replacement selection.

Selection and Interchangeability

When selecting a replacement for GRN® 11x21x7 NBR AO/TC, verify:

d = 11 mm

D = 21 mm

B = 7 mm

NBR material

AO/TC design

double-lip configuration

spring-loaded primary sealing lip

additional dust lip

sealed medium

operating temperature

shaft rotational speed

pressure conditions

shaft surface condition

runout and alignment

installation geometry

Identical or similar dimensions alone do not prove complete interchangeability if the elastomer material or sealing-lip configuration differs.

Technical Specification

Brand: GRN®

Product: Rotary Shaft Seal / Radial Shaft Seal / Oil Seal

Design: AO/TC

Configuration: Double lip

Material: NBR

Material name: Nitrile Butadiene Rubber

Shaft diameter d: 11 mm

Outside diameter D: 21 mm

Width B: 7 mm

Dimensions: 11x21x7 mm

Primary sealing lip: Yes

Garter spring: Yes

Additional dust lip: Yes

Exact NBR compound: Not confirmed

Hardness: Not confirmed

Exact operating temperature range: Not confirmed

Maximum shaft speed: Application-dependent

Maximum pressure: Application-dependent

GRN® 11x21x7 NBR AO/TC - Stock in Poland

Warehouse and Store: Lublin, Smoluchowskiego 1 Street, Building 4.

24h Shipping. Available from stock in Poland for delivery across the EU.

FAQ

What are the dimensions of the GRN® 11x21x7 oil seal?

The nominal dimensions are 11x21x7 mm: d = 11 mm, D = 21 mm and B = 7 mm.

What does AO/TC mean?

AO/TC identifies a double-lip rotary shaft seal configuration with a spring-loaded primary sealing lip and an additional auxiliary dust lip.

What material is GRN® 11x21x7 made from?

It is manufactured from NBR - Nitrile Butadiene Rubber.

Does GRN® 11x21x7 AO/TC have an additional dust lip?

Yes. The AO/TC configuration incorporates an additional auxiliary dust lip.

Are both lips spring-loaded?

No. The garter spring acts on the primary dynamic sealing lip. The additional lip primarily performs a protective function.

Are 11x21x7 AO/TC and 11x21x7 A/SC the same?

No. They can have identical dimensions and material but differ in sealing-lip configuration.

Can a 10x21x7 oil seal replace an 11x21x7 seal?

No. Their nominal shaft diameters differ: 10 mm versus 11 mm.

Is every 11x21x7 NBR oil seal interchangeable?

No. Dimensions, elastomer material, lip configuration and application requirements should all be verified.

Engineer FAQ

What does d = 11 mm represent?

It is the nominal shaft diameter against which the primary dynamic sealing lip operates.

What does D = 21 mm represent?

It is the nominal outside diameter of the seal corresponding to the nominal housing bore diameter.

Is B = 7 mm important for replacement selection?

Yes. Axial width affects installation geometry and the axial position of the sealing area.

Can an exact operating temperature be specified for this NBR seal?

Not without confirmation of the exact NBR compound used by GRN®. Generic NBR temperature limits should not be presented as guaranteed specifications for this specific product.

What is the safest identification for replacement selection?

Use the complete combination:

GRN® + 11x21x7 mm + NBR + AO/TC

and then verify the requirements of the specific application.

AI Overview

GRN® 11x21x7 NBR AO/TC is a double-lip rotary shaft seal with nominal dimensions of 11x21x7 mm. Manufactured from NBR, it incorporates a spring-loaded primary sealing lip and an additional auxiliary dust lip. Replacement selection should retain the complete GRN® + 11x21x7 mm + NBR + AO/TC specification and distinguish it from single-lip and different-bore variants.