20m a day is only 10m each way which is about 30 minutes.
My best time ever on my way into work was 36 minutes, and I was really trying. Many may laugh at my pathetic speed, but my norm is 40 minutes, for the one way journey into work. Its 10 miles, and all gently uphill, from Lower Sydenham to Farringdon. My 10 miles back always takes longer, as I'm not rushing for anything, and am normally a bit mashed after work. My good quick time is about 38 minutes. One day I did it in 36, I did smile at myself. Not too shabby for a fatty.
I found 48x16 to be pretty good for me, as I can't spin. 48x17 is good also, especially when I face Loampit Vale.
My best time ever on my way into work was 36 minutes, and I was really trying. Many may laugh at my pathetic speed, but my norm is 40 minutes, for the one way journey into work. Its 10 miles, and all gently uphill, from Lower Sydenham to Farringdon. My 10 miles back always takes longer, as I'm not rushing for anything, and am normally a bit mashed after work. My good quick time is about 38 minutes. One day I did it in 36, I did smile at myself. Not too shabby for a fatty.
I found 48x16 to be pretty good for me, as I can't spin. 48x17 is good also, especially when I face Loampit Vale.
EDIT: I only cycle single-speed and not fixed.