I began with a 42 x 18t (63") and have worked up to a 52 x 16t (88") with a 44 x 16t & 52 x 18t to keep them company. The higher gearing is certainly a challenge on hills, but I found trying to spin up a hill in the 63" more difficult. I like the control that a high gear gives, and the 40 mph at about 150 rpm is nice too. Most of my rides include hills or rollers.