Dodgy track pump?
Have recently invested in my first track pump (Joe Blow Turbo) and notice that when I've pumped my tyres up to ~120 psi it becomes very hard to detach the head of the pump from the valve. This culminated today in me ripping the valve from the inner tube. Have I got a dodgy pupm, or am I doing something I shouldn't be? Can't keep forking out for new inner tubes every couple of months!