Vespa Simmerringe bgm PRO

bgm PRO shaft seals made of high-quality and ethanol-resistant (E10) FKM/Viton®*

New: Now also for Vespa Wideframe, GS3, Faro Basso etc.: We have expanded our shaft seal portfolio with modern Simmerrings from bgm and can now offer shaft seal rings made of FKM / Viton® for almost every classic Vespa:


The bgm PRO Simmerrings have the perfect dimensions that guarantee easy installation, optimum function and a long service life. The large shaft seal on the clutch side, e.g. on old Vespas, has an overall height of 7mm on the bgm PRO, instead of the 6.5mm usually used by other manufacturers. This means that the bgm PRO oil seal is based on the original Piaggio factory specifications. If you have ever taken apart an old and original Vespa engine, you may have noticed that a large oil seal with a height of 7mm was installed at the factory.


On old engines, the bearing of the crankshaft is ‘floating’. This means that the bearing is not fixed and it can be moved axially (horizontally sideways) in the engine housing. This displacement occurs, for example, under load due to the axial force exerted by the helical-toothed primary drive. If the crankshaft shifts too much, this can of course affect the ignition and also the function of the clutch. The aim should therefore be to have as little unnecessary play as possible. The stop and thus the play of this floating bearing in the Vespa engines is determined only by the oil seals. The tolerances in the old engines are large and, for example, we also use thicker housing seals today, so it makes sense to use 7mm oil seals!


The material FKM (fluorocarbon rubber) is extremely resistant against

  • Heat
  • Friction and
  • Fuel
  • Ethanol

Even super petrol fuel E5 in Germany currently already has up to 5% ethanol admixture, with E10 it is even up to 10%, and the trend is rising. And did you know that this can vary from country to country? Have you ever noticed in France, for example, that your engine runs differently? In other countries, the ethanol/alcohol content can be significantly higher. A conventional oil seal cannot tolerate this increasing ethanol content and can swell or soften when it comes into contact with ethanol-containing fuels. The bgm PRO FKM/Viton® shaft seals, on the other hand, offer lasting protection. In addition, our Simmering with Viton® is twice as temperature-resistant as conventional (blue) NBR shaft seals. Further advantages of these modern shaft seals:

  • extremely impermeable to gas
  • and very resistant to ageing


OK, so our radial shaft seals from bgm have

  1. optimal dimensions and
  2. most modern materials

but what are they suitable for now? An engine equipped with bgm PRO FKM/Viton® shaft seals can also be used without problems in engines that run on E10 fuel (10% alcohol content). The modern and high quality brown Viton®* sealing material is

  • permanently resistant to ethanol/alcohol and
  • also suitable for engines with high temperature
  • and high speeds.

bgm PRO FKM/Viton® shaft seals are therefore suitable for all engines! Just play it safe and install the modern Simmerrings right away. Whether for an original engine, mild tuning or extreme tuning and motorsport! For reasons of environmental protection and in favour of maximum flexibility of the sealing lip, we deliberately refrain from additionally coating the sealing lip with PTFE/Teflon®*


The bgm PRO shaft seals offer double sealing as an additional feature: All shaft seals that seal to the outside, to the atmosphere, have a so-called dust lip. This is positioned in front of the actual sealing lip and holds the seal in place

  • Dust,
  • Dirt and
  • Moisture.

This further increases the very good stability.


The bgm PRO oil seal set improves the installation clearance and offers an extremely long service life due to the excellent modern materials FKM/Viton®, combined with perfect fuel compatibility: it is even E10 resistant! The oil seals replace the old ones and of course fit without modifications. Tip: We offer the Simmerrings individually as well as in sets and in sets with bearings!

Select the matching bgm PRO Simmerrings here
*Viton®/Teflon® are registered trademarks of DuPont Dow Elastomers

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