I am rebuilding an old Pinarello cyclocross bike. The hubs are WTB's with grease guards and are in very good condition. The freewheel is a Durace and is six speed. It had been set up with a SIS Deore XT shifter set on a flat bar. Did the old SIS set ups require a different chain? I bought what was called a six speed chain and it seems to shift just fine. However, when it is on the small chainring in the front, it appears to be rubbing slightly on the inside of the large chainring and crank. Do I need to switch to a more modern, narrower chain and if so, will a 7-8 speed SRAM or 9 speed SRAM work? I don't want to purchase several different chains if I can avoid it.