The bikes stay upright because the tires fit snugly between the wooden slats. This DIY bike rack by @hamsterwheelbikerepair is made with just wood and screws! The diagonal pieces hold the bike tires.

If you want to build a hanging bike rack or organize your garden tools ... if you own one -- and some wood glue. These shelves will be very strong but also heavy once complete, so it's a good ...