Since the summer of 2017, the Singapore-based bike rental company Obike has operated a fleet of several hundred free-floating bikes throughout Zurich. You simply download its app and register your credit card and then you'll be able to see where the closest bike is located. Book it, find it, unlock it with your phone and then hop on. After you've finished using it, simply leave it at any public bike parking spot. 30 minutes will cost you 1.50Sfr and you're required to leave a deposit of 49Sfr, which is refundable anytime. The bikes have just on gear and are fine for short distances within the city centre, but aren't really suitable for hills.