I did a forty miler yesterday morning. Didn't seem too bad setting out so I took my fixed gear. It became very windy and cold shortly after I left and I did the last 20 miles or so through open countryside with no shelter being pelted by hailstones and into a hellish head wind at 10 - 11mph, struggling to maintain a decent cadence on a gear that was way too high for the conditions. My legs were burning.
If only some bright spark could invent a device which allows a cyclist to have a selection of about 18+ gears to choose from....