How to inflate a bike tire

Tire pressures affect speed, effort, cyclist comfort and the risk of punctures. The more the tire is inflated, the more uneven the terrain is felt. A tire that is too inflated can also reduce performance by slowing the transmission of energy on certain surfaces.

To inflate a bicycle tire, it is better to use a pump equipped with an indicator (manometer), that is to say a dial that indicates the pressure of the air. This pressure is usually given in 2 units of measure : the bar (1 bar = 14.5 PSI) and the PSI (Pounds per Square Inch) (100 PSI = 7 bar)

The right pressure will depend on the type of tire, the rider's weight, the temperature, the weather conditions and the surface on which you ride.

A mountain biker inflates his tires slightly (2.5 to 3 bar), so as not to feel too much bumps, roots, pebbles. While a racing cyclist gives them a pressure three times stronger (6-8 bars), because they must first maximize their effort.

The pressure that can support a tire is indicated on its side (the minimum pressure called also low pressure and the maximum pressure also called high pressure) : beyond it it is likely to burst. As it gets older, a tire cracks and bears less pressure. It will be better to replace it because a well inflated tire reduces the pedaling effort, and to have a better braking.

1 / Inflate a bicycle tire with a Presta valve :

After removing the dust cap, loose the small brass cap on the valve stem. Then press your finger on the valve until a "pshitt" is heard to release the air. Check that the tip of the pump has a narrower opening. If the valve loses air when attempting to screw the pump tip, screw the small valve nut a little so that it is not pushed back by the nozzle.

2 / Inflate a bicycle tire with a Shrader valve :

Remove the cap, then, in case the valve is seized, unblock it by pushing the small stem with the tip of your finger or with an improvised tool (pen, piece of wood, key). We must hear a "pshitt". Check that the tip of the pump is of large diameter.

It is necessary to check regularly the pressure of your tires and adapt it according to the surfaces but also of your sensations to obtain a better performance and to keep the pleasure of rolling because even the tires in good condition lose air.

Different models of pressure gauges and bicycle pumps exist : Pumps and manometers for bicycle. Be careful, choose a pump that can provide the correct pressure for your tires because some models have a capacity of less than 7 bar.

3 / How to use CO2 to inflate a bike tire ?

CO2 cartridges are an another way than the pump to inflate bicycle tires or tubulars in case of puncture, whether in training or competition. They are practical (easy to transport), fast and easy to use.

However, a CO2-inflated tire will tend to deflate faster. The CO2 molecule would pass more easily through the latex or rubber, unlike the nitrogen molecule present in the air provided by a conventional bicycle pump. The CO2 cartridges will then be used in case of possible repair.