that I feel as though a clogged intestine is let loose
Oh, dear... !! That is not a feeling I associate with my bike, at all!! (Too much bran, yes; my bike, no.)

I get what you mean; just that phrase... conjured up something very different in my mind!!!

For me, riding a bike is like horizontal flying. It's fun, and even when I don't feel much like riding -- there are plenty of times I don't really feel like it -- I will go ride anyway, because I always, always feel better after I ride.

I have only one bike. It probably is not the best fit for me, and certainly it needs some things replaced (such as the right grip), but it has taken me many places, helped me through heartache, made me stronger, brought me to beauty and peace, and had its .... er... spokes in many laugh-out-loud moments and all-around good times. It's not what inspired my then-small son to refer to me (me!) as "the athletic parent," but it is what inspires this old couch potato to live up to that designation and his view of me as athletic (me!) as best I can.