Today I wanted to change out the 30 tooth chain ring on my 9 speed Ultegra triple for a 26 tooth chain ring. The 26 tooth chain ring is a Sugino Brand with 74mm spacing. The switch over was uneventful, but the smaller chain ring caused the chain to catch and rub on the next larger 42 tooth chain ring pickup protrusions. No matter what I did the chain would rub ever so slightly. It seems like the Sugino chain ring needs a spacer between the ring and crank?
Any suggestions? Where am I going wrong? I really want to go lower than 30 tooth if I can. The chain is a Wippermann chain.