Hello, I have an Alan Super Record with a Super Record rear derailleur. Don't know what year exactly; the derailleur is pictured in a 1984 catalog and has black trim and titanium bolt, if it helps. Until now I have used the derailleur with a 31T rear cog with good results. Now I plan to install a 34T freewheel. Will a 34T rear cog work or am I pushing my luck? Will it even fit?