How to Fix a Flat Tire on a Mountain Bike

Video Transcript

"Hi, I’m Debbie, and this clip will be about how to change a flat. When you’re out trail riding, any number of things can cause you to get a flat. You can get a puncture from a thorn or you can pinch flat from having an improper tire pressure. The first thing to remember about your tire and your wheel is that they are locked together. So the first thing you want to do is get it off the bike and use your thumbs and fingers to break the seal. Go all the way around the wheel busting the seal. You want to bust it on both sides too. Hopefully you have a pack with you that contains all the required equipment to change a flat. Bend back the tire, place the tire tool, and then coax it off the rim. Take off one side of the tire. Often there’s a small bolt that holds the tube in place. Remove this pull back the tire, lift the stem out and pull out your tube. Next you want to look for what caused the flat. On the outside I look for thorns and cuts, and on the inside, with my fingers, I feel for a piece of glass or a thorn. If you find a thorn, you want to of course remove it. When you are satisfied that whatever caused you to have the flat is not there take out the new tube. Remove the ring, this type of valve is called a presta valve and you can actually put air into it without a pump. You want to put in enough air just to give it some form. Close the valve and pull back the tire. And put the stem in. Having a little bit of air helps put the tube in the tire. Now remember, the tire and the rim go together so we have to put the tire back on the rim. I use my thumbs starting at the stem. Make sure that you don’t pinch the new tube between the tire and the rim. When you get it almost on you can take your tire levers, pop it back on, and make sure it’s seated all the way around. Now we’re ready to put some air in it. In my packet, I have a CO2 cartridge, which is easier than a pump. When I put it together it’s going to puncture the CO2. Open the valve, place the cartridge on, and as soon as I puncture it, It’s gonna fill up. Wiggle it off, close your valve, tighten down the set screw again, and check your pressure. Sometimes you may have to use more than one CO2 cartridge. And This is how to change a flat tire on the trail. "