Picture yourself having recently acquired a brand-new bike. When you need to check its tire pressure, you see a different kind of valve. After some research, you find out it’s called a Presta valve.
In this case, how would you check your tire pressure?
Presta Valve vs. Schrader Valve
As insignificant as it may look, valves play an important role in your bike tire. There are two main types of valves –and a third one called Woods or Dunlop, but we’ll leave that one out for today.
Schrader valves are the ones you find in cars and most regular bikes. Their circumference is of the same width, top to bottom.
Looking at its tip, which is threaded to allow a dust-cap for protection, you’ll see a pin. This is the spring valve. It needs to be pressed in order to let air flow through. Schrader valves are generally covered in rubber.
For racing bikes, this is a great advantage, as it needs less space than Schrader valves, and weighs much less –no counterbalance is needed.
Another difference from Schrader valves is that they are threaded all the way down. This is to allow adapters, in case of need. They also have a valve, its nut being the thinner part on its tip.
Unlike Schrader valves, Presta valves seal tightly on air pressure, which means no spring valve is required.
How to Check Bike Tire Pressure with Presta Valve
Even though they have a different system when compared to Schrader valves, checking bike tire pressure with a Presta valve is not a difficult task.
This video does a good job in explaining how to check your bike’s tire pressure (credit to Mazon99):
There are some things to bear in mind when checking your tire pressure.
One key factor is not to unscrew the valve nut entirely, as air will flow freely and, of course, deflate your tire. Another one is that, depending on how modern your pump is, you may need either a new one which allows this kind of valve, or an adapter.
There are some “smart” pumps, which allow both types of valves through the same opening. Otherwise, some pumps have two openings. Presta valves require the smaller one in this case.
In order to check your bike’s tire pressure with a Presta valve, you can use a pump with a gauge.
First, unscrew the valve nut on its tip. To make sure it is correctly done, apply some pressure with the tip of your finger. Air should flow out of the tire and seal back again once you stop pressing. This is also useful to “clean” the valve before inflating it.
Engage the correct pump to the valve, and read the information on the gauge. You can also use a stand-alone gauge to do this and follow the same procedure. Just be aware that, as you check the readings, air may slightly come out, and the exact pressure will be lost.
So, if you’re choosing this last option, it is recommended to pump a little extra before reading, so that you can decide when to stop leaving air flowing out.