Fix a Flat Tire

Steps

1. Remove the Wheel: Remove the affected wheel from the bike. If it's a rear wheel, shift to the smallest cog first to make it easier to pull the wheel out.
2. Deflate Completely: Press the valve core to release any remaining air in the tube.
3. Break the Bead: Use your hands to push the edges of the tire toward the center of the rim. This "unseats" the bead and makes it easier to get the levers in.
4. Lever the Tire: Insert one tire lever under the tire bead and hook it to a spoke. Insert the second lever a few inches away and slide it around the rim to pop one side of the tire off.
5. Remove the Tube: Reach inside and pull the old tube out. Leave the tire on the rim (one side attached) to make reinstallation easier.
6. Find the Culprit: Carefully run your fingers along the inside of the tire casing to feel for thorns, glass, or wire. Caution: Be gentle so you don't cut your fingers! If you don't remove the cause, your new tube will flat instantly.
7. Install New Tube: Add just enough air to the new tube to give it shape. Insert the valve into the rim hole and tuck the tube inside the tire.
8. Reseat the Tire: Use your thumbs to push the tire bead back onto the rim, starting at the valve and working your way around. Avoid using levers for the last bit if possible, as they can "pinch" the new tube.
9. Inflate and Check: Pump the tire up to the recommended pressure (check the sidewall). Ensure the tire bead is seated evenly all the way around the rim, then reinstall the wheel.

Tips

• Always check your tire pressure before every ride. Most flats are "pinch flats" caused by running pressures that are too low.
• If you're having trouble getting the last bit of the tire bead back on, try "massaging" the tire toward the center of the rim all the way around—this gives you a tiny bit more slack.
• Carry a spare tube even if you run tubeless; it's the ultimate "get home" insurance.