I run 23-25 Conti lightweight tubes in Conti 4000s11's 25 inflated to 95 front and 105 back with air. Morning ride to evening ride I'm ok. Over night I drop 5-10 lbs easy. Before the conti tubes I ran spec tubes no difference. If OP can run run month or two on 23's with no air he 's gotta special tubes.
Prathmann, I was aware that thinner tubes do bleed air as well. I thought I'd keep it simple as Schreader valves typically on your thicker tubes and Presta on thinner. However, I did listen to two guys discussing this very topic to death one day. The one guy an engineer maintained they had done testing for one of the tire companies and the presta valve itself bled air contrary to everyone's belief. He said they submerged inflated tubes and videoed them over 24 hrs. That was his story, sounded like he had all the facts????