Dynamic Seals

Radial Shaft Seals

The Simmerring®

The original and its innovative advances

Simmerrings® seal rotating shafts reliably and are used in millions of applications and a variety of equipment in general industry and the automotive sector. This radial shaft seal ring is based on know-how gained from years of experience. It continually undergoes further refinement based on the latest technological developments, and is particularly functionally reliable, flexible and extremely stressable.

Always “up-to-date”

The tried-and-tested original Simmerring® keeps up with the times. Our experts have continued to develop it, for example, with improvements in seal lip profiles. This has made it possible to further improve its reliability and functionality across a broad range of applications. The improvements include a friction-optimized design to decrease fuel consumption, which leads to reductions in CO2 emissions.

Freudenberg Sealing Technologies offers a comprehensive selection of products suited to a variety of requirements. The range is further expanded by creating combinations with other components and additional functions.

Simmerrings® must be adapted to varying operating conditions to achieve friction-free operation:

  • Diameter and rotational speed of the shaft 
  • Temperature 
  • Pressure 
  • Dirt accumulation from outside
  • Dirt accumulation in the assembly to be sealed 
  • Media to be sealed off (lubricating oil or grease, other liquids, paste-like or gaseous media)


The professional solution for your task

Our selection includes Simmerrings® adapted to all these parameters and different ranges of use. You can find more information about them in our product catalog.

The advantage:

  • High functional reliability: The Simmerring® minimizes downtime and ensures reliable operation. 
  • Long operating life: This increases the operational efficiency of your facilities and equipment, along with the security of the investment. 
  • Easy mounting: Simmerrings® can be mounted quickly. This saves time and reduces costs.

Our products in detail



For the development of the innovative Gerromatic G 61 our engineers have taken nature as a role model. The special design of the sealing lip distributes the pressure, so that a wider contact zone for the fluid film between the shaft and sealing lip is used. The benefits for the process industry are better friction, less wear and a low heat generation, which extends the lifetime of the seal.
RWDR Simmerring 75 FKM 260466

75 FKM 260466

The material innovation of Freudenberg Sealing Technologies for industrial gear units is called 75 FKM 260466. This especially wear-resistant material made of fluoro rubber has been especially developed for use in synthetic oils, especially polyglycols (PGs). These lubricants are used in power transmission aggregates, such as worm gears, for various reasons. With the coordinated combination of 75 FKM 260466 and PGs, the challenges of sealing edge wear and shaft inlet can be mastered and operating life increased compared to other seal materials.

Sealing Modules

As integrated solutions, Sealing Modules have the advantage of using fewer components, offering easier installation, reducing weight and saving space.
Blue Seals


The BlueSeal design and its low friction PTFE POP® lip are based on long experience with the PTFE Simmerring®. The weight savings of 40% and an installation space reduced by 50% support future requirements for emissions reductions.
RWDR Simmerring CMS


The Contact Minimized Simmerring® (CMS) delivers greater durability with less friction for the small shaft diameters, 5-20 mm, typically found in sensor, actuator, pump and throttle applications.
RWDR Simmerring ESS


The Energy Saving Seal® (ESS) minimizes friction on the crankshaft and camshaft and in transmissions. This significantly reduces fuel consumption and emissions. The reduction of friction also extends the seal’s operating life while increasing the machine’s reliability.
RWDR Simmerring Kassettendichtungen

Cassette Seals

Cassette Seals consist of a Simmerring® and an optimized wear sleeve (either hard or soft unitized). They are used to seal shafts in heavy construction and agricultural equipment that, for example, are exposed to high stresses. They also effectively protect engines, transmissions, differentials and axles against dirt, water and other environmental influences. The latest developments in elastomers also make it possible to achieve optimal sealing without a spring. This reduces friction even at high temperatures. Combi seals consist of a Simmerring® (individual or double lip) and a polyurethane wiper. They increase the protection against external contaminants while allowing axial and rotary movement.
RWDR Simmerring Kombidichtungen

Combi seals

Combi seals consist of a Simmerring® (individual or double lip) and a polyurethane wiper. They increase the protection against external contaminants while allowing axial and rotary movement.
RWDR Simmerring LFS


The low-friction Simmerring® (LFS) is a combination of advanced, high-performance and friction-optimized ACM materials.
RWDR Simmerring Lube Seal

Lube & Seal

The customer benefits all around when – and only when – the seal and the lubricant work in perfect harmony – with friction-free processes, cost-effective systems, and market-driven solutions. Based on this insight, Freudenberg Sealing Technologies and the Freudenberg Group’s Klüber Lubrication have bundled their ground-breaking know-how to create Lube & Seal, an innovative sealing system from a single source.
RWDR Simmerring PTFE POP


The PTFE POP® seal (= Power Optimized PTFE) demonstrates its robustness as a PTFE Simmerring® by adjusting material and geometric characteristics for minimal friction.
RWDR Simmerring Encoder

Simmering & Encoder

The combination of a Simmerring® with an integrated encoder not only seals the shaft reliably but captures its rotational speed as well. The collected data are fed into the engine control unit, allowing the optimization of the combustion process. The result: less fuel consumption and lower emissions. Other advantages include a reduction in the number of components and in the size of the installation space, along with easier mounting and a decrease in weight.

Related documents

Sales Sheets


The original Simmerring® is a premium quality radial shaft seal conforming to DIN 3760 and ISO 6194-1 with an elastomeric outer diameter. The Simmerring® can be used in numerous original equipment applications across a broad spectrum of market segments (e.g., gearboxes, transmissions, axles, engines, and pumps).


Since 1929, the Simmerring® has stood for outstanding quality and today is known worldwide as a synonym for radial shaft seal rings.


The Freudenberg Sealing Technologies Imperial Standard Range (ISR) Simmerring® shaft seal is a premium quality seal typically used in applications such as gearboxes, axles, transmissions, and engines.


Medium pressure seals, such as the BABSL, can be used in many applications including pumps and motors in hydro-units, mechanical power transmission gearboxes, and 2-stroke engines.


Typically, with medium pressure seals, high friction and hollow wear occur due to pressure deformation at the elastomeric flex section of the seal—resulting in an enlarged contact band width.


The BlueSeal is one design suited for future engine dynamic sealing. This patented radial shaft seal technology offers weight savings of 40 percent compared to a conventional seal, and it requires only half as much installation space.


Freudenberg Sealing Technologies radial shaft Energy Saving Seals (ESS™), demonstrate significant reduction of power loss in drive assemblies as opposed to standard sealing elements. By combining a special elastomer and a revolutionary new design, this shaft seal is able to maintain the pressure force at a consistently low level over a wide range of RPM, even at a higher sealing operating temperature. The low radial force of the main lip ensures the optimization of sealing function, abrasion resistance, and friction.


The High/Low Pressure Seal (HLPS) from Freudenberg Sealing Technologies is a field-proven, specialty-designed high pressure radial shaft seal. The HLPS is a severe duty pressure seal and has a unique design with several features that greatly improve its overall performance.


The Freudenberg Sealing Technologies Imperial Standard Range (ISR) Oil Seal is a premium quality seal typically used in applications such as gearboxes, axles, transmissions, and engines.


Values to the customer. ACM 380DF: better relaxation characteristics and bigger temperature range (–40°C to 175°C) compared to classic ACM. Lower friction compared to conventional sealing lip profile: 15 to 20%.


MileMaker is engineered for superior performance. The new MileMaker heavy duty wheel seals deliver significant energy savings and increase the reliability and durability performance expectations for wheel seals in the heavy duty truck and trailer industry.


The Freudenberg Sealing Technologies PTFE POP Seal is designed for reduced friction in automotive drive assemblies as opposed to standard sealing elements.


Freudenberg Sealing Technologies Track Roller Seals (Floating Seals) commonly used in heavy equipment and construction machinery are noted for their reliable seal endurance characteristics. These durable seals are resistant to moisture, natural contaminants such as sand and fiber, and harsh weather including radical temperature fluctuation, ozone, and extended UV radiation.


The Freudenberg CASSETTE-S4 is the most advanced Freudenberg solution for construction and agriculture mobile machinery wheel hubs and undercarriage applications.

Relevant market segments

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