On Tue, Dec 8, 2009 at 10:35 AM, Bicycle Specialties
> Harvey Sachs ridicules the Campag Sport single roller rear derailleur. The Sport was perfectly good for the purpose for which it was designed, that is Italian "around town" bikes with three sprockets, typically 16-18-20. There must be thousands of such bikes on the streets of Italy today, many of them still running around with those 1950s three speed derailleurs. Trouble is that North Americans couldn't understand why the Sport wouldn't handle a much wider range of gears than it was designed for. It wasn't a cheap version of the Gran Sport but a derailleur aimed at a much different market. A market just about unknown in North America.
> Now the Gran Tourismo. That is probably the worst derailleur that Campagnolo ever made or perhaps anybody else for that matter.
The Sport was a stupid idea because it couldn't do anything that a 2 pulley couldn't and it couldn't do things a two pulley could. There was no upside to single pulley designs, hence their quick and permanent demise. I'll bet the sprung upper pivot even cost more to make compared to an unsprung equivalent than the amount saved by using one less pulley.