Assuming the OP's crankset is 110 BCD, this might also be an option: https://www.interlocracing.com/shop/...triplizer-2808

It replaces the original inner chainring with a 34 or 36T ramped and pinned ring, with mounting points for a 74BCD inner ring, thereby creating a triple set where there was originally a double. A new wider bottom bracket may also be needed.