The only real difference you'd notice is that a larger ring will produce a lower chain tension and thus a longer chain life, plus a longer life for the rings and cogs, since more cogs contact the chain at a time. Over thousands of miles, you'll notice slightly longer chain life. On the tandem, I've been running the big ring down to the 3rd cog, the 26T. Tandems are hard on drive chains, and I notice the difference.