Originally Posted by
desconhecido
When we were kids, Schwinn made a bicycle with a two speed coaster brake rear hub. To the best of my recollection, the hub was by Bendix. What visually differentiated the two speed coaster brake hub from the single speed Bendix coaster brake hub were several red bands painted on the two-speed. It is my recollection that there were grooves/indentations in the two-speed which were painted, but I never examined one sufficiently close to tell. On the net, there are some pictures of two-speed Bendix hubs with the bands painted yellow, but I remember red.
The way that the hub worked was by a very slight backwards torque. Too slight to engage the coaster brake, almost unnoticeable, but it would shift between the two gearings. I never owned one of these bicycles as they were way too expensive for us, but I did ride several owned by wealthier friends and my recollection is that they worked very, very well. My guess is that the two gears were low, and direct -- sort of like the two lower speeds on an AW hub. But that's a guess.
Probably, in addition to the colored bands there will be some sort of marking either on the hub itself or the coaster brake frame bracket which will identify the hub, though that's a guess too.
http://www.bunchobikes.com/auto.htm
For the Bendix version, the two-speed hubs are substantially larger than the regular coaster brake hubs.
I think there were two of the two-speed models: red and yellow. One has ratios for a smaller wheel (yellow, I think). In the US, anyway, the two-speed hubs are somewhat rare (that is, you'll see a very large number of bendix coaster brake hubs for every one two-speed that you come across).
Fichtel und Sachs also made a two-speed hub (I believe these are regarded as superior).
Edit: Ah, better info here:
http://www.trfindley.com/pgbndxhbs.html
Originally Posted by trfindley
The Automatic hub was made from 1960 to 1969. It was last listed in the 1970 Schwinn Catalog.
There were 3 types of Automatic Hubs, identified by band color: Red, Yellow, and Blue bands. The Red Band was made 1960-1964. The Yellow and Blue Bands were made 1965-1969.
The red and yellow band hubs have a low gear: 1 sprocket turn for .67 hub turn to go up hills easier. High gear is 1:1. The hubs would go on bikes with 26" and 24" wheels. They were also used on bikes with 20" wheels and 46-teeth sprockets. The red and yellow hubs have some different parts in them that won't interchange. Check the diagram for the different brake parts of each hub.
The blue band has 1:1 low gear, and high is overdrive: 1 sprocket turn for 1.5 hub turn. These are used on bikes with 20" wheels and 36-teeth sprockets to go further on flat roads.