Lifting it. Folders tend to get carried more than regular bikes. There are also folks who have to carry their bikes up steps,or even several floors. Weight also comes into play when working on the bike;putting it in a stand or turning it over. Had a guy bring his Euro-style Electra to my clinic this week;I had him hold the bike while I clamped it into the stand. So glad I'll never have to fix a flat on any of the bikeshare bikes.