Originally Posted by Sy Reene

I don't know what kinda pump head that is.. My more pedestrian Joe Blow (Topeak) only extends down a total of 1.5cm. However from that, the gasket in the head (which is what people are worried about wearing out) only begins about .5cm from this furthest point. So IOW the clamping of the pump head is going on from about .5cm to 1cm below the end of the valve stem. Pretty sure it's not hitting the extra threads of a threaded-valve-stem type, but for sure is hitting the cap threads anyway.