Fichtel & Sachs Duomatic & Automatic
Fichtel&Sachs has produced several types of kickback two speed planetary-gearhubs: Duomatics. They came on the market in 1964; the low-gear is the direct-drive. There were two models: the 101, a two speed freewheel hub, and 102 a two speed with coasterbrake. The type 101 is rare.
All duomatic hubgears by Fichtel & Sachs, have code for the production year . Often found beside the abriviation “F&S” or beside the spokenumber. In FIG.1a we can see the logo Torpedo changes after 1966 (J); on the left we see the modern logo 1967 (K).
(G =1964; H =1965; J =1966; K =1967; L =1968; M =1969; N =1970; O =1971; P =1972; R =1973; S =1974; T =1975; U =1976; V =1977; W =1978; X =1979).
From ' 74/ ' 75 there is a code on the brakelever, and sometimes a second code for the month .
In FIG.1a we see the type 102 the left , on the right is the 101. Beside the F&S mark on the shell, we can see the code of the production year (J for 1966 and K for 1967); the writing of the word “Torpedo” was changed after 1966.
FIG.1a The first series Duomatics; left type 102, with a coasterbrake and on the right type 101 without brake, produced from '64'- '73
The 102 , FIG.1b, was often used in foldingbikes, which were starting to become popular after the introduction of the Moulton Stowaway. The quality of chrome, sealing and bearings of the first series of Duomatics is better, than the later versions. Furthermore the flattened axle could handle the torque.
FIG.1b Exploded view hub 102
FIG.2 The hubs Automatic A 2110 en Duomatic R 2110 are almost identical; the Automatic is somewhat wider.
FIG.3: in 1973 they produced a new version of the 102, labeled R2110; the oil-nipple disappeared. The axle is round now and the torque should now be handled by the dented friction bearingcone on the drive side of the hub. The dented cone must grip firmly into the dropouts of the frame. Do not use shims on the inside of the frame! The round axle will rotate and the bearings of the hub will turn tight.
FIG.3 Exploded view of the Duomatic hub R2110.
It always has a coasterbrake; production ceased early eighties.
In 1974 Sachs introduced a new automatic shifting hub, based on the R2110: the A2110 Automatic. This is a rare product. The gearshifting is done by flywheel action at a certain rotation-speed of the hub. There were two versions: the redband and the blueband. The redband needed a higher rotation-speed to shift, and was used in small-wheeled foldingbikes.
http://hubstripping.wordpress.com/fs-torpedo-automatic/ ; maintenance instructions in english: http://sheldonbrown.com/sutherland/CB-IGH-3-sachs.pdf
FIG.4 EXPLODED VIEW OF THE AUTOMATIC HUB A 2110
The production of Duomatics/Automatics ceased around 1980, but there is a rivival of those two old gear/brake systems.
SRAM started making new Automatics recently! http://mccraw.co.uk/sram-automatix-review/ ;
Sturmey Archer started making new Duomatics! http://hubstripping.wordpress.com/2010/09/23/sturmey-archer-s2c/
OTHER MANUFACTURERS WITH SIMILAR OLD HUBS (1960s/1970s)
BENDIX 'AUTOMATIC' 2-SPEED HUBS (1960s)
From 1960 to 1969, the American firm Bendix made a 2-speed hub, (called the "Automatic"), with a coaster brake. The gears were changed by back-pedalling. This hub was made in several different versions, each version was marked with 3 coloured bands around the hub body.
They had 3 Red bands (1960 to 1964), or 3 Yellow bands (1965 to 1969), or 3 Blue bands (1965 to 1969), for 20" small wheel bikes.
Generally these hubs were used for beach bikes, and cruising models, by large volume cheap bike makers (like the American 'Schwinn' brand). In Europe, these hubs are hard to find. For further information about Bendix hubs see the American website : www.trfindley.com/pgbndxhbs.html
SHIMANO 'AB-100 AUTO-2' AUTOMATIC 2-SPEED HUB (1975)
In 1975, Shimano Introduced a new automatic shifting hub, (named the 'AB-100 Auto-2'). This hub used a similar mechanism design to the Sachs A2110 hub, where the gear shifting was done automatically, without rider control, based on the centrifugal motion of two small fly-weights against return-springs (at low rotational speed the springs move the fly-weights inwards, at high rotational speed the weights fly outwards against the springs, and engage the higher gear). The Shimano AB-100 Auto-2 was unique and different from the Sachs A2110, because it was fitted with a large plastic ring on the outside of the hub, next to the drive sprocket (14T to 20T). By rotating this plastic ring, (clockwise or anti-clockwise), the rider could increase or decrease the spring tension inside the hub, regulating the speed when the hub shifted gear. The plastic became fragile after a few years and shifting ring was easily damaged. Like the Sachs A2110 this was also an unusual product, and like the A2110 the gear shifting was done by flywheel action, depending on the rotation speed of the hub. Probably only a few thousand AB-100 Auto-2 hub gears were ever made, so they are now extremely rare, and very difficult to find, especially in an unbroken and working condition.
STURMEY ARCHER S-2 TWO SPEED 1966
Sturmey-Archer (UK) also proved they could make a two-gear (no brake) hub, which shifted by pedaling backwards ; they named it the 'S2' ; the high-gear was the direct drive ( their new S2 model has a low-gear direct drive! ).