Woho, I made it! After one month of neglecting the issue, I managed to repair my bicycle. After a night ride home, I encountered a flat tire the next morning.
After I made up my mind on changing the inner tire, I found, that the outer part of the tire had seen better days and needs a change as well. After some time of procrastination, I finally decided on two new outer tire parts and mounted them on the weekend. And I have to say: I love it. It’s perfect. Never went my bike so smooth on concrete streets. And I have to say, I am kinda proud of myself. Usually I would leave bike repairing to my grand dad or dad, but this time I managed all by myself! :) The small journey to Neuenburg (30km one way) on Sunday went fantastic, too!