Newbie - how to approach building stamina for road cycling
I have a newbie question on how much stamina do I have to have to begin road biking for distance.
I have a raliegh hybrid which I ride 8 miles a day at less than 10 mph. I've gone periodically to the local bike trail and usually do 13 miles at < 10 mph. I'd like to try a weekly trip that goes 23 miles with a halfway stop for breakfast. The speed has to be 10-12 mph. To test my stamina, I went to the local trail and did 6 miles at 15 mph, nonstop. I went a total of 8 miles that day because the temp was around 90.
My question is how to approach being confident that I can complete the 23 mile trip without making a fool of myself. I also ride a stationary bike 20 minutes a day with pretty good tension. Is there any kind of recommended program someone could suggest? On the daily rides, I ride with my wife. I can't increase the mph on those. Any suggestions would be welcome.