Pump It Up

Keeping your tires within the recommended psi (pounds per square inch) helps cut down on pinch flats and makes it easier to go faster. With the pressure up at the higher end of the recommended range will reduce the rolling resistance, making it easier to go faster. Keeping it at the lower end will provide more traction and a smoother ride, though at the cost of some speed.

But how do you know what the minimum and maximum recommended psi are? The sidewall of almost every tire will have the recommended psi listed. If you can’t make it out, or are just trying to get home to better light, a good rule of thumb is 30-65 psi in a mountain or comfort bike tire, 50-80 psi in a hybrid tire, and at least 90 psi in a road tire. It is always better to know your exact range, though.

Most modern bicycle pumps will work with either a Presta or Schrader valve.
Presta Valve
Air compressors work mostly with Schrader valves, and make it fast and easy to pump up your tires.
Schraeder Valve

To inflate the tire, you need to determine what kind of valve you have. Then determine if your pump is compatible – if you’re using a gas station air compressor, it won’t work with Presta unless you have an adapter. If you have a Schraeder valve, a standard air compressor will work.

That seems an argument strongly in favour of Schraeder, for the sake of convenience. But Presta, with the narrower size, allows for the manufacture of wheels which are stronger and have a deeper dish, making them more aerodynamic. This is why Presta is much more common on bikes designed for speed, like road bikes.

An air compressor is also only one of several ways to inflate a bicycle tire. There are also bike pumps that stand on the floor or attach to your bicycle frame, as well as C02 inflaters that can be small enough to fit in an under-seat bag.

With an air compressor, remove the valve cap and, in the case of Presta, unscrew the top and then screw on an adapter. Then simply press the air chuck to the valve and hold it firmly in place as the tire fills with air. When the tire is filled to the desired pressure, simply take off the compressor and then replace the cap. With Presta, don’t forget to screw the valve closed.

With a bicycle pump, ready the valve, then flip up the thumb lock lever to lock it on and make sure the air is going where it’s supposed to. Pump until the gauge shows the recommended pressure, or, if the pump doesn’t have an integrated gauge, until the tire feels firm. When the tire feels firm take the pressure with your gauge by pressing it onto the valve. If the pressure is lower than you would like, pump more air in. When you’re done pumping, flip the thumb lock lever back to resting against the barrel of the pump, remove the pump from the valve, and put the cap back on the valve. With Presta, screw the valve back tight before replacing the cap.

A floor pump will be easier to use to inflate your tire than a frame pump, since you can set it on the floor and get more leverage. Floor pumps also usually have longer and wider barrels, which means more air in each press. A hand pump, though, can mount on your frame, so that you always have it with you.

With a C02 inflater, you need both the inflater and a cartridge of C02. C02 cartridges come in different weights; 12g is enough to fill most tires adequately. For high-pressure road tires, 16g can be preferred. There are also 40g cartridges which are suitable for multiple refills, but only if the seal can be made absolutely tight. C02 is ideal for filling flats on the road, as the supplies are small and light.

To inflate a tire from a C02 cartridge, first ready your valve. Then make sure the CO2 cartridge is loaded properly in the inflater and place the inflater over the valve. Engage the inflater, which will open the cartridge. Allow the tire to fill with air, disengage the inflater, remove it, and replace the valve cap. CO2 is less than ideal for topping up tires that are just low, because it’s so hard to get that perfect seal that would let you use the cartridge multiple times. So CO2 inflaters work best as emergency flat repair in conjunction with a pump or air compressor for everyday maintenance.

Everyday maintenance is important, since tubes leak air over time, much the way even the most tightly-tied balloons eventually go flat. If you’re riding frequently, you should check your tires once a week. If you’re riding less frequently than once a week, checking your tires every time you go out will prevent nasty surprises on the road. Tires which are low are both slower to ride on and more prone to pinch flats, both of which can keep you from fully enjoying your ride.

We’re more than happy to fill your tires for you for free any time you stop by.

Images courtesy of Wikimedia Commons

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