Simmer ring/radial shaft seal designs

Simmer ring/radial shaft seal designs

Item designation in the store: dd-DD-WW XX
dd = Shaft diameter in mm
DD = Outer diameter in mm
WW = Width in mm

All dimensions are separated using a "-" minus sign. Spaces in the designation are not permitted!

XX = Code letters for the design type (see below), e.g. BA, BASL, BAOF, B1, B2, VIT.

Shaft seals without dust lips

Design BA

For shaft seals, certain speeds are specified depending on the peripheral speed of rotation. On request, we can provide you with a chart which will allow you to easily see the speed for a given shaft diameter.
Standard shaft seal, DIN version A, original manufacturer Simrit version BA Standard shaft seal. We stock them in a number of standard diameter sizes from 6 to 450 mm.


Description The BA version is the ideal shaft seal for many applications. It has a sealing lip. Seals to approx. 0.5 bar of pressure, therefore keeping unpressurised oil in a housing, for example. Higher pressures than 0.5 bar are not possible with the BA version.

The outside of the BA shaft seal is made entirely from NBR elastomer, a black rubber (acrylonitrile-butadiene rubber).

A metal reinforcing ring is completely and invisibly vulcanised. A tension spring made from non-stainless steel pushes the seal lip against the guided shaft.

Alternatives to the BA shaft seal

  • BA shaft seals have no protective lip against dust and dirt. If you require a shaft seal with a dust lip, order the BASL version.
  • We also have shaft seals made from FPM/FKM (“Viton” brand name) for significantly higher speeds, temperatures over 110 degrees Celsius and better chemical resistance even against “aromatic hydrocarbons” (petrol). These have the suffix VIT.
  • If the tension spring has to be made of stainless steel, we recommend ordering small quantities of the VIT design (see below). We can source BA shaft seals with stainless steel springs for quantities over 100 pc. and 1 – 4 months delivery time.

B1 design

Standard shaft seal, DIN version B, original manufacturer Simrit version B1

Metal version of the BA design. The metal ring is open; it is not vulcanised. It is therefore easier to push in than the BA version. The sealing effect of the outer ring is not as high as the BA version and should therefore be installed with sealant if required. The B1 shaft seal is closed on one side and open on the other. It has a regular steel spring.

B2 design

Standard shaft seal, DIN version C, original manufacturer Simrit version B2

Solid version of the BA design. Metal ring, closed on both sides. Can handle extreme loads, even when installed in confined spaces. Includes spring.

VIT design

Shaft seal made from FRM
VIT version; very durable. Made from DuPont "Viton" (fluorine rubber, also referred to as FPM/FKM). Provides outstanding resistance against heat up to 200 degrees Celsius and even beyond this if with a shorter service life. Tables can be found on DuPont’s website. VIT is compatible with oils and acids, petrol, benzene, other fuels, vacuum, ozone and silicone oils. Significantly higher speeds (2 to 3 times) than with BA/BASL shaft seals are also possible.
The spring is made of corrosion-resistant and acid-resistant steel 1.4301 (according to Dichtomatik data sheet). Details available on request.

Shaft seals with dust lips

BASL design

Standard shaft seal, DIN version A, original manufacturer Simrit version BASL BASL BA shaft seal with SL protective lip (shown in red in the diagram), made from NBR rubber as with the BA version.

B1SL design

B1 with SL dust lip. Metal ring, closed on one side. Includes spring. This item is not always in stock.

B2SL design

B2 with SL protective lip. Reinforced design. Metal ring, closed on both sides. Includes spring. Only certain sizes in stock.

Special designs

BAOF design

Special springless version; otherwise the same as the "BA” version.


Storing shaft seals

Generally 5 to 25 degrees Celsius, in dark environment, 70% air humidity, maximum 5 – 6 years for NBR shaft seals (BA, BASL, B1, B2, BAOF) and 9 – 10 years for FPM/FKM shaft seals (VIT). However, the shaft seals we stock do not get old as they sell quickly.
Ozone, created by laser printers, electric motors and certain lamps for example, is particularly harmful. If shaft seals are placed on PVC or metal, chemical processes may take place over time. Rubber products are best stored in their original packaging and used quickly.

Order sizes not listed in the shop by special procurement

For seals in inches, O-rings and other sealing products not listed in the shop, we would happy to make you a personalised offer. Send us your enquiry by e-mail or use our contact form. We look forward to your message.


These key points are to provide you with initial, general information. For definitive information, please refer to the data sheet which we will happy to send to you on request. You can also find a wealth of practical information on the manufacturers’ websites.