Have you thought about changing the chain rings instead? I ride something like a 50-45-26 crank and a 14-28 freewheel. I never use the granny around town, but I can climb walls with it if needed. Having a half-step granny gives lots of different gear ratios for cruising. I would worry about shifting performance with such a large rear cog, but, of course, I am not all that familiar with new technology. My newest bike is celebrating its 20th birthday! Hell, I would take off the integrated shifters/levers and stick a pair of old-fashioned friction shifters on the downtube, as God intended…