I've explored the limits of this derailleur; you can almost certainly do better than a 28T cog. Not sure if you can get enough swing to go more than 7 speeds, though; that's the most I used it on.
Here's mine eating 34T; which it would only do if the axel was positioned at exactly in the right spot in the dropout. The length of the derailleur hanger (which varies a bit from bike to bike, I think) also makes a difference.
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● 1971 Grandis SL ● 1972 Lambert Grand Prix frankenbike ● 1972 Raleigh Super Course fixie ● 1973 Nishiki Semi-Pro ● 1979 Motobecane Grand Jubile ●1980 Apollo "Legnano" ● 1984 Peugeot Vagabond ● 1985 Shogun Prairie Breaker ● 1986 Merckx Super Corsa ● 1987 Schwinn Tempo ● 1988 Schwinn Voyageur ● 1989 Bottechia Team ADR replica ● 1990 Cannondale ST600 ● 1993 Technium RT600 ● 1996 Kona Lava Dome ●
Last edited by Lascauxcaveman; 04-28-14 at 01:00 PM.