This kind of ratio ( 56 ) works good in Vienna. It is not exactly flat here, in fact it goes up and down all the time. But (and here comes the point) the inclination of the roads is not very steep, instead they go up or down for long distances. That means riding on very high speed (half of the time). With a smaller gear I felt much like riding a sewing machine. Some of the upward-hills need extra attention ofcourse.