In this tutorial, we learn how to fix a flat with a CO2 cartridge. Start out by grabbing the bag that is underneath your bag, which has everything you need to fix your flat tire. After this, take the wheel off and find out where the hole is located. There will be a hissing sound coming from this spot where the air is escaping. First you will remove the tube from the wheel, then replace it with a new one. Once you're finished, use a CO2 tube to fill the tire back up with air. Replace this back on the bike, then enjoy riding and have fun!