I've only had my bike a few weeks and have been lucky enough to not have any flats yet. I have a question regarding changing flats when you're out riding. I have tubes, a mini pump, and tire levers in my seat bag, but how do you gauge tire pressure if you change a flat during a ride? The normal small portable gauges are just for shrader valves. I've watched some YouTube videos on changing tires and everyone seems to gloss right over it. What am I missing?