Inflate a Tire with a Presta Valve

Once exclusively seen on road racing bikes, Presta valves are now very common on all types of bikes.

Step-by-step guide

To inflate a Presta valve, 

1. Remove the black plastic cap covering the valve, if present. If there isn't one, don't worry. The Presta valve design prevents dirt, water, or other contamination from entering the valve.
2. Unscrew the knurled nut on the top of the valve as far as it will go (don't force it!)
3. Use a Presta capable pump or compressor and press or thread it on to the valve. Or, thread on a Presta-to-Schrader adapter to use pumps or compressors designed for typical automotive style valves.
4. Inflate to your desired pressure, within the limits specified on the tire sidewall.
5. Remove the pump and thread the black plastic cap back on the valve, if desired.