I was feeling pretty beat when I got home last night, 1st full week fixed (5 days, 120 miles straight commute and then there were errands). I think it's the mileage not the gearing but whatever, the route and the bike are both still pretty new to me. Interesting, this was the 3rd week of this route and my 8 yr old was finally picking up an almost the whole thing (his share of the whole thing, he does 8 of my 24 commute miles per day), not consistently going the wrong way at each turn any more. Although actually he went on a 16 mile ride w/ his camp in the middle of the day too, so he earned some time in the comfy chair w/ his ds for sure.