>Hi group, I may be wrong but I always had the impression long
>horizontal dropouts were needed for double fixed rear hubs.{1930's
>and 40's road racing} The two sprockets could be somewhat different
>tooth counts Eg. optimum for flat terrain, plus one with a higher
>tooth count for hills.
By the 1930, most European racers used a 3-speed freewheel on one side of the hub, and a fixed cog on the other side. Obviously, without a chain tensioner, you needed a long dropout to take up the chain slack. (The Campagnolo Cambio Corsa was a way to automate the shift, rather than having to get off the bike.)
By that time, French cyclotouring bikes with derailleurs already used vertical dropouts. Cyclo introduced those in the early 1920s...
The Super Champion dropout makes sense when you consider that back then, many bikes had a 3-speed freewheel with a Super Champion derailleur and a single fixed cog on the other side of the hub. The 1939 Oscar Egg in "The Competition Bicycle" is a good example. So you get a 4-speed, of which three cogs are freewheeling and can be shifted on the move, but the fourth (smallest) cog is fixed and shifted by flipping the rear wheel around.
I imagine the 2-position dropout helped when flipping the wheel from the fixed cog to the freewheel - no need to align the wheel correctly, as it dropped into position. Since you did that during the race, any help is useful.
If you wonder why the racers didn't just use a 4-speed cog - there are a variety of reasons. One important one is chainline. Through the late 1940s, racers refused to run the chain more than one cog off the perfect chainline. And as Jack Taylor pointed out in the Bicycle Quarterly interview (Summer 09 issue), the long chainstays on older racing bikes also served to keep the chainline as straight as possible.
Jan Heine
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