The thing with fail-safe ("pannen-sicher") bicycle tires is that you need to run them with higher pressure than many touring bikes usually operated with, the lower the pressure, the smaller the security benefit from that tire is. That's why I have them at 5 bars, which is not little for touring bikes. Dunlop valves are described to hold up to 6 bars. Presta valves originally were only used for racing bicycles, since the tires are narrower and are put under much higher pressure (10-13 bar). Dunlop valves cannot hold that. so in racing sports the Presta has it's meaning, but why they are being used for touring bikes as well is beyond me.
The Schrader valve is described for pressure up to 4 bar (max), it is often used for car tyres, too. You find it on mountain bikes where the tires are wider and higher pressures are not so much wanted.
I will give the bike to a shop on Monday and ask them, my thoughts are to go back to Dunlops valves. I am needing the thing for it is my only means of mobility, and I travel up to 120 km away from my home town by bike. Getting caught by a technical failure in some forsaken area and 50 km away from home may not be life-threatening, but it is NO FUN nevertheless and means only trouble and discomfort.
Until Tuesday evening, Skybird is grounded.
