"The first problem -- I hear some noise coming from the crank, especially when I shift to the 5th gear. The last Saturday I went to the store, but they were looking at the front wheel, since I was not sure at that time where it is coming from. I have the feeling (maybe I'm wrong) that something is also slowing the bike."

Hi Bagel007 - I have the same problem with my Giant Cypress bike, there is a clicking noise coming from the crank, when I put any pressure on the right side pedal with my foot, especially going up hill. I have taken it to a bike shop but they couldn't test it out as no hills! Not sure what to do about it. Did you ever find out what the problem was please? I would be very interested to know if so. I was told the bike has a sealed crank. The bike is pretty good except for this annoying problem. Kind Regards Wendy B