Fichtel & Sachs Torpedo AUTOMATIC (A 2110)
General:
When the AUTOMATIC hub was developed the DUOMATIC hub was already on the market. This was the Wirtschaftswunder (booming economic) years in Germany. Even the sky was no limit anymore. With this background the developers and engineers from Sachs in Schweinfurt had a heroic goal.
Developing a 2 speed hub with a pure mechanical AUTOMATICAL shifting mechanism and without any kind of bowden cables. They achived already a pure mechanical shifting mechanism without bowden cables with the DUOMATIC. Now the next objective was to automate the shifting mechanism.
This was a tricky but the solution was found. The centrifugal force! A force which is was never used again in the history of internally geared hubs.
While reaching a certain rear wheel cadence (rotation frequency) a centrifugal weight moves to a outer position and shifts from gear one into gear two. When you reduce the cadence the centrifugal weight will stay in the outer position and shifts down in the moment you´ll reduce the pedal force.
The shifting point for the AUTOMATIC hub was defined between 16 – 18 km/h. To achive this feature for different wheel sizes there were two versions available:
- Red Version (see picture above) for 20″ up to 24″ rear wheels (centrifugal weight 15 gr.).
- Blue Version (see picture above) for 26″ up to 28″ rear wheels (centrifugal weight 15 gr.).
The shifting point is defined by a little spring which is in contact with one of the centrifugal weights. This means that the centrifugal bodies have the same weight (15 gr./body. I stripped the hubs and checked this!)
This is great because stretching or pushing this little spring makes it easy to optimize the shifting point for your purpose.
When you use the Red version in a 26″ to 28″ wheel the shifting point will be at a higher speed (19 – 20 km/h). The Blue version will shift at a lower speed in a 20″ to 24″ wheel (10 – 14 km/h).
The AUTOMATIC hub is the only hub which uses the centrifugal force to shift between the two gears. The DUOMATIC hub was already a never reached kind of autarkic mechanism with fantastic german Maschinenbau competences indside. Beside the DUOMATIC hub the AUTOMATIC represents the edge of mechanically shifting internal geared hubs.
This hub is the rarest Fichtel & Sachs hub. It was produced since 1966 and only for a few years. The customer prioritized the amount of gears higher than a maintenance and adjustment free hub! The majority of these hubs comes with 28 spoke holes for the Klapprad 20″ purpose. Only a minority with 36 holes. These were hubs were mainly sold in the Netherlands, Denmark and Sweden. There were some all year cyclists in these countries who rated ease of maintenance and adjustment higher than the amount of gears. Two are enough!
The AUTOMATIC internal gear hub owns 2 gears:
Gear 1 Ratio 1:1
Gear 2 Ratio 1:1,36
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