GRN® Rotary Shaft Seal 300x340x20 NBR 70 Shore A TC - Double Lip Oil Seal

GRN® Rotary Shaft Seal 300x340x20 NBR 70 Shore A TC - Double Lip Oil Seal

GRN® Rotary Shaft Seal 300x340x20 NBR 70 Shore A TC is a large-diameter, double-lip radial shaft seal with dimensions 300x340x20 mm. Manufactured from NBR (Nitrile Butadiene Rubber) with a nominal hardness of 70 Shore A, it features a spring-loaded primary sealing lip, an additional dust lip and a rubber-covered outside diameter. The original AO construction functionally corresponds to the commonly used TC double-lip configuration.

Technical data

300x340x20 mm dimensions

The designation 300x340x20 mm defines:

300 mm - nominal shaft diameter
340 mm - nominal housing bore diameter
20 mm - seal width

This is a large-diameter rotary shaft seal. When selecting a replacement, the dimensions should be checked together with the NBR material, 70 Shore A nominal hardness and double-lip construction.

What does AO/TC mean?

For this product, AO identifies a double-lip rotary shaft seal construction featuring:

• a spring-loaded primary sealing lip,
• an additional secondary dust lip,
• a rubber-covered outside diameter.

In international English-language product terminology, this construction is commonly described as TC - Double Lip Rotary Shaft Seal.

Seal designation systems can vary between manufacturers. Therefore, AO and TC should not be treated as universally identical manufacturer codes. The actual seal construction should always be verified when selecting an equivalent.

NBR 70 Shore A

The sealing element is manufactured from NBR (Nitrile Butadiene Rubber) with a nominal hardness of 70 Shore A.

In the designation 70 Shore A:

70 indicates the nominal hardness value of the elastomer, while Shore A identifies the hardness scale used for flexible elastomeric materials.

The letter A in Shore A should not be confused with an oil seal construction code.

NBR is one of the most widely used elastomers in rotary shaft sealing technology and is commonly used with mineral oils and greases. Actual suitability depends on the specific medium and operating conditions.

Double-lip TC construction

The GRN® 300x340x20 NBR 70 Shore A TC incorporates two lips with different functions.

The primary sealing lip operates directly against the rotating shaft surface. A garter spring helps maintain contact between the sealing edge and the shaft.

The additional dust lip faces the external environment and forms an additional barrier that helps reduce the ingress of dust and other contaminants towards the primary sealing area.

TC vs SC

The key difference is the additional dust lip.

TC - double-lip construction with a spring-loaded primary sealing lip and an additional dust lip.

SC - single-lip construction with a spring-loaded primary sealing lip and no additional dust lip.

A 300x340x20 TC and a 300x340x20 SC can have identical basic dimensions but different sealing constructions. They should not automatically be considered interchangeable.

TC vs B1

The designs differ in both lip configuration and outside diameter construction.

TC - double-lip design with a rubber-covered outside diameter.

B1 - typically a single-lip design with a metal outside diameter.

Matching the 300x340x20 mm dimensions alone is therefore not sufficient to confirm interchangeability.

Function of the 300x340x20 oil seal

A rotary shaft seal operates between a rotating shaft and a stationary housing.

The primary sealing lip helps retain a compatible lubricant or other medium within the operating area. The additional dust lip provides an extra barrier against external contamination.

With dimensions of 300x340x20 mm, this product belongs to the large-diameter rotary shaft seal category. The exact application should be confirmed from machine documentation or the specifications of the original seal.

Alternative designations and search references

This product may also be encountered under the following descriptions:

• GRN Rotary Shaft Seal 300x340x20 NBR TC
• GRN Rotary Shaft Seal 300x340x20 NBR 70 Shore A
• GRN Oil Seal 300x340x20 NBR TC
• Oil Seal 300x340x20 NBR TC
• 300x340x20 AO NBR 70 Shore
• 300x340x20 NBR AO
• 300x340x20 NBR TC
• NBR Oil Seal 300x340x20
• Double Lip Oil Seal 300x340x20
• Shaft Seal 300x340x20 NBR TC

Selecting a GRN® 300x340x20 NBR TC seal

Before ordering, verify:

• shaft diameter 300 mm,
• housing bore diameter 340 mm,
• width 20 mm,
• NBR elastomer,
• nominal hardness 70 Shore A,
• AO/TC double-lip construction,
• spring-loaded primary sealing lip,
• additional dust lip,
• rubber-covered outside diameter,
• sealed medium,
• operating temperature,
• shaft surface speed,
• shaft sealing surface condition,
• requirements of the specific sealing arrangement.

Matching the 300x340x20 mm dimensions alone does not guarantee full interchangeability.

Installation

Before installation, thoroughly clean the shaft and housing bore. The shaft surface in contact with the primary sealing lip should be free from sharp edges, burrs and damage.

The seal should be pressed evenly into the housing around its entire circumference without tilting or deformation. Uniform installation is particularly important for large-diameter seals.

The spring-loaded primary sealing lip should normally face the medium to be retained.

FAQ - GRN® Rotary Shaft Seal 300x340x20 NBR 70 Shore A TC

What are the dimensions of this GRN® oil seal?

The dimensions are 300x340x20 mm: 300 mm shaft diameter, 340 mm outside diameter and 20 mm width.

Is the 300x340x20 TC a double-lip oil seal?

Yes. It features a spring-loaded primary sealing lip and an additional dust lip.

What does NBR 70 Shore A mean?

It identifies NBR (Nitrile Butadiene Rubber) with a nominal elastomer hardness of 70 Shore A.

What does TC mean on an oil seal?

For this product, TC identifies a double-lip configuration with a spring-loaded primary sealing lip, additional dust lip and rubber-covered outside diameter.

What does AO mean?

AO is the original construction designation for this product. Its functional configuration corresponds to the commonly used TC double-lip design.

What is the difference between TC and SC?

TC has an additional dust lip, while SC is a single-lip design without an additional secondary dust lip.

Does Shore A refer to the seal design?

No. Shore A is a hardness measurement scale for elastomeric materials. It does not identify the seal construction.

Can any 300x340x20 oil seal be used as a replacement?

No. Dimensions, material, hardness, lip configuration, outside diameter construction and operating conditions should all be verified.

GRN® Rotary Shaft Seal 300x340x20 NBR 70 Shore A TC - key information

GRN® Rotary Shaft Seal 300x340x20 NBR 70 Shore A TC is a large-diameter double-lip oil seal with dimensions 300x340x20 mm. It is manufactured from NBR with a nominal hardness of 70 Shore A and features a spring-loaded primary sealing lip, additional dust lip and rubber-covered outside diameter.

GRN® rotary shaft seals have been part of the TG Ersatzteile Polska product range since 2007. Available from simmering.pl, a specialist supplier of rotary shaft seals, bearings and industrial sealing solutions. Stock in Poland with worldwide shipping.