Ok, so I know this will sound stupid to most, but I am a beginning cyclist (only have been riding consistently for a couple of months) and am wondering how people ride such long distances with ease. I typically ride 4 miles or so each way to work most days of the week...sometimes I add a couple of extra miles going somewhere else on my trip home. This I do (mostly) with ease. However, I got a new bike and rode home from the bike shop (25 miles) and was utterly exhausted when I got home- I don't know if I could have gone much further. I also have been wondering how much more endurance I might be able to have on flat stretches as opposed to hills, but really haven't been able to test that theory. I live NE of Atlanta, GA and hills are everywhere. Also, I just stopped smoking approx a month ago. I am sure this has something to do with my endurance, but even when I didn't smoke years ago I just was never that strong at cardio activities. I am really wanting to do some group rides and longer charity rides, but am scared I will not be able to make it. Any advice? How long did it take you to get into "long" rides?