You can spend a lot of money for a decent bike wall mount. This one is pretty cheap and easy to build:
Materials: Frosta stool, screws, self-adhesive rubber pads
Take 2 Frosta legs and saw off about 10 cm (depending on the width of your handlebars).
You might use sand paper to clean the edges.
Mount the legs to the wall as seen in the pictures.
Attach the rubber pads where the bike will be placed later.
~ by Patrick