Any rider making long journeys should have this in their kit. Those 4 tiny valves you see prevent air from escaping. Sometimes they loosen from exposure to heat, dirt, cold, and most importantly, the constant rotation of tires. The rubber seam on the valve becomes brittle over time due to the weather and breaks off. If this is the case, you will get a tire leak (which is similar to the symptoms of a flat tyre, but is not). All you need is to remove the entire valve with a screwdriver (largest…