Sachs Torpedo Automatic A2110
The F&S Torpedo Automatic model A 2110 produced from the mid-seventies to the mid-eighties is a centrifugal auto-shifting two-speed hub that, although initially produced in much fewer numbers than the contemporary Duomatic R2110 hub, later became very popular and the mechanical design was also the basis for the later SRAM Automatix hub from the 2010s.
Two variants were produced: A blue banderole version meant for 24-28 inch wheels and a red version meant for 20-22 inch wheel. The only mechanical difference between the two is the torsional spring that holds back the centrifugal weights. The blue shifts earlier into second gear than the red.The general consensus is that the blue version generally shifts too early for getting proper pedaling cadence at lower riding speeds and the red version's shifting point is actually better suited for 28"/700c wheel sizes. The spring can be modified to change the shift point:
(See also the Automatix page for more information regarding the spring modification)
The hub partially disassembled:
(Note: The small driver ball ring was broken on this particular hub, so it was replaced by loose bearing balls.)
There are more disassembly photos of the Automatic hub model on the Duomatic page.
Diagram with measurements for wheel building and fitting into a frame:
See also the complete parts list in German, English and French.
Page last updated 2024-08-24 17:56. Some rights reserved (CC by 3.0)