Swap in a spare tube with a CO2 inflator

Carry a spare inner tube and a CO2 cartridge inflator so you can swap out a punctured tube and be riding again in under five minutes. This is the fastest flat-repair method, favored by racers and group riders who need to minimize downtime.

Steps

1. Remove the wheel and tube: Release the brake, remove the wheel, use tire levers to unseat one side of the tire bead, and pull out the punctured tube.
2. Inspect the tire: Run your fingers along the inside of the casing and remove any glass, thorns, or wire that caused the flat.
3. Install the spare tube: Inflate the new tube just enough to give it shape. Insert the valve stem through the rim hole and tuck the tube inside the tire.
4. Reseat the tire bead: Push the bead back inside the rim with your thumbs, working from opposite the valve toward it.
5. Inflate with CO2: Thread a cartridge into the inflator head, press it onto the valve, and release the gas in a controlled burst. One 16 g cartridge fills a standard road tire to roughly 100 psi.
6. Remount the wheel: Seat the wheel in the dropouts, tighten the quick-release or axle nuts, and re-engage the brake.

Tips

• Match cartridge size to tire volume: 16 g for road tires, 25 g for gravel or mountain tires
• CO2 permeates through butyl rubber faster than air; top off with a floor pump within 24 hours
• Patch the punctured tube at home so it becomes your next spare