i have done 20, and i was definitely warmed up! lol... i talked with one guy at the gym... had trimmed down some... after taking up biking. he was doing some of those 150 milers on the weekends. as i ride, i wonder how in the heck... does the tail end survive... ? lolI used to consider a 20 mi bike ride a warmup, and every WE we did 60-70 mi one day.
But now, 20 mi seems good enough for me!
To ride long distance, you have to do it often, and I have so many other things going on now, and almost all my riding friends no longer do it.
ymmv
this would be me at mile-30!