Probably to make them a little lighter, most bicycles are now sold without kickstands, which makes them hard to park for the simple dash into the post office.
A simple way to make a bike stand up by itself wherever there is a curb or other low, curb-like object, such as a low wall, raised flower bed, or suitable rock. For this trick to work, the curb must be higher than the lowest place on the pedals' rotation and lower than the highest place; it works best when the curb is about three to five inches high.
First, the bike is placed against the curb, with the rear wheel touching, the front wheel slightly turned into the curb and touching also, and the bike slightly leaning away from the street. Then the crank is rotated backwards until the curbside pedal is flat against the curb. The bike will stand on its own, balanced by the two tires and the pedal. The bike can't move backwards or forwards due to the tires and the pedal.
