I got the Klic Floorpump for Christmas and every time I use it it pulls my valve core out of my tire. The way it goes on it threads to the presta valve but when I go to take it off it just unthreads the valve and spews air everywhere...rendering it useless. I thought it could just be my setup but after trying on girlfriends bike and others it does the same thing. WTF this overpriced piece of junk! Has anyone else had this problem with either this pump or similar pumps that thread to the presto valve? Am I just an idiot. Waste of money IMO, and annoying. Glad it was a gift...