Originally Posted by
IK_biker
If the tubes use presta valves with removable cores, find a suitable tool and tighten the cores into the valve stems.
I have the experience that even a very high-quality (Schwalbe) tubes often come with slightly loose cores.
VC-1 Valve Core Tool | Park Tool
This tool would do, but there are many others, and you could improvise a bit.
Good point. I had a brand new tube (Continental) a year ago where the core popped out after I pumped it up the first time! A couple of times, before I got it down tight. I don't know how but the adapter or pump was loosening it up and unscrewing it.