How the *bleep* do I fill this up?
If you have to ask, chances are your bike is not equipped with the type of valve pictured above.
This is a typical Schrader valve, found not only on the majority of bicycles, but also familiar to anyone who's ever filled up a car tire. If the tire is low, simply apply the head of any pump or gas station compressor firmly to the tip of the valve, and blow.
But don't take it for granted that your bike comes equipped with the common Schrader valve. You may have to spend some more quality time with your valve if it looks more like this:
Meet the Presta valve. This is the one that causes bike riders to throw their hands up in exasperation on the first encounter.
When you remove the cap from the Presta valve, you will see a pointy tip with a small brass lockring snugged down around it. To open the valve in order to add or release air, you must loosen this ring by turning it counterclockwise. Don't worry, the ring will not come off. But now the valve is open, and you can test it by pressing on the tip with your finger to release some air.
You'll have to complete one more step to pump air into the tire. With the valve in the open position, as shown, place a Presta adapter on the valve by screwing it onto the tip:
Now you can treat it just like a Schrader valve, and fill it up with any standard air compressor or car pump. When you are done filling the tire, make sure you remove the Presta adapter, and re-tighten the brass ring around the valve tip to keep air from escaping while you ride.
To make your life a little easier, most bicycle pumps available on the market today come with dual or universal heads that allow you to fill up either Presta or Schrader valve without the use of an adapter. Before venturing out, practice using your pump with the type of valve you have, to make sure you will know how to fill up your tire should it go flat on the road.
And, just in case, we recommend carrying a Presta adapter with you. Many times it is easier and quicker to fill up tires with a gas station compressor than a portable pump.