If you had asked me this 6 months ago I would have said 10 miles; 3-4 months ago, 15; 2 months, 20. But since I have been off the bike for 3 weeks now and sidelined for the remainder of the season, 1 mile is a long way. For me short has always been about half to 2/3 of my most regular distance covered. So if you normally ride 20, the about 10-12 would be short.