You can use an air compressor to fill a bike tire much faster than you can with a manual pump, but there are a few things you have to watch out for – especially if you are trying to air up the tires of your mountain bike at the gas station.
The important thing to keep in mind when using an air compressor with your tire is to always be in control at all times.
Road bike tires, in particular, have so little volume that it’s all too easy to pump air too quickly, having disastrous results for your tube.
With the right adapter and set up, though, an air compressor will get you back on the road or trails sooner and with more energy to spare.
Why Proper Bike Tire Pressure Is Important
For serious bike riders, every little bit of upgrade can go a long way to improve the performance of a bike.
Lightweight components, frames, and fancy shifting equipment can have a drastic effect on how far you can take a bike – but they all hardly compare to one of the biggest improvements you can give to your bike: a set of properly inflated tires.
Proper tire pressure does so much for improving the handling and riding comfort of a bike, which makes it worth the investment of having an air compressor ready to give your tire a quick air boost before you take it out for a ride.
Proper bike tire pressure is important, but many bike owners forget a simple fact of owning a bike – tires leak air over time. There’s not a lot of air in a bike tire in the first place, so even a tiny leak can have a big effect on your bike’s performance.
What’s more, the ideal pressure for your bike tires depends not only on the type of tires that you have but also on how much you weigh. With a bit of practice and experience, you will be able to figure the perfect tire pressure soon enough.
1. Check Your Tire Pressure
All bike tires leak air over time, but some types can go flat more quickly than others. If you have a pair of tubeless tires that are fairly new and properly sealed, then you may get away with checking your tire pressure a bit less often.
Bike tires that have butyl tubes are also able to keep their pressure a bit longer compared to lightweight latex tubes.
Also, if you happen to have one or more of your tires just repaired or patched for a flat, or refilled with CO2 canisters, then you may need to re-check the tire pressure the next time you try to bring it out for a ride.
Patches can have their own leaks, and CO2 leaks and seeps through the tire wall more readily than plain air, so your tires will probably need topping off sooner than you may expect.
Finally, the type of valve that your tires have will also have an effect on how quickly your tires lose air.
Bike tires that have Schrader valves (the ones that are the same size and shape as your car tire stem valves) tend to leak just a bit more air compared to the more slender Presta valves.
Your bike likely didn’t come with a bike tire pressure gauge, so it’s always a great idea to invest in a good digital gauge just for your bike.
Your floor pumps or your air compressor may come with their own gauges, but these gauges measure the pressure near the pump and not at the tire itself, which means they tend to be less accurate.
Next, check your bike tire’s tire pressure depending on the type of valve you have. If you have a Schrader valve, then you measure it the same way as you do with your car tire.
Unscrew and remove the valve stem cap and put it somewhere safe like in your pocket. Press the tire pressure gauge over the valve stem – if you hear a hissing noise, or you can feel air leaking out, press the gauge down harder. Wait for the indicator to stabilize, and then take your reading.
If you have Presta valves, then you will need to remove the valve covers first. Then unscrew the valve cap at the top – don’t worry about taking this part off, since the valve cap will not come off the valve stem even if you keep turning it.
Tap the end of the valve cap to test if you opened it all the way – you should sense that air is coming out when you press it. Then push the pressure gauge down on the valve all the way, until the indicator stabilizes and you can get a reading.
2. Determine Your Ideal Bike Tire Pressure
As a general rule, the wider the tire, the less pressure it needs to maintain its proper shape and handling characteristics.
Fat mountain bike tires need only 25 to 35 pounds per square inch or PSI. On the other end of the scale, narrow road bike tires will typically need 80 to 130 PSI. Tires designed to be somewhere in between, which are sometimes called hybrid tires, require around 40 to 70 PSI.
Check the tire wall for the maximum air pressure that the tire is designed for, and carefully note that number.
You do not want to exceed that pressure, and you may have to set up your air compressor to avoid any chance that you blow up your tires by exceeding its maximum PSI rating.
The ideal pressure for your bike tires are likely in the middle of the range they are designed for – 30 PSI for a mountain tire is a good place to start, for example. You do have to factor in your body weight, though.
A rider weighing 200 pounds may need to run their mountain tires at 32 PSI, while a lighter 165-pound rider may find that 28 PSI is already plenty. In any case, never exceed the maximum tire pressure recommended by the tire manufacturer.
3. Air Up Your Bike Using Your Air Compressor
If your tires need to be aired up, then it’s time to take out the air compressor (or just roll the bike up next to your compressor unit). First, adjust the PSI for your compressor before turning it on.
After that, plug the air compressor to its power source and let it accumulate pressurized air. Read off the gauge to make sure you have the air tank at the pressure you want.
Depending on the type of bike tire valves you have, you may need to invest in an adaptor.
For tires with Schrader valves, the inflator nozzles designed for car tires will fit these valves with no further adjustment necessary – just push the nozzle on the tire valve stem all the way until you get a good seal.
If you do have Presta valves, which are more common in the narrow road bike tires, then you can buy an adaptor for that from just about any bike shop.
These adaptors are very inexpensive – you can get them for a dollar or so, and it’s probably a good idea to buy a spare or two since they’re so cheap.
When filling up a tire with a Presta valve, then the same procedure applies as when you are reading the tire pressure using a gauge. First, remove the valve cover and then unscrew the valve cap all the way up.
Test to see if the valve is open by tapping the end and checking if air comes out. Once the valve is open, then you can attach the air hose by plugging the Presta valve adaptor all the way down until it covers the shaft of the valve stem.
When filling up a tire, try to do it at a very slow rate. The volume of air that larger air compressors can put out will easily exceed the maximum capacity of a bike tire, and opening your compressor valve all the way could lead to a blown tube or even a tire blown completely off the rim.
Patience is the key here, especially if you are doing this for the first time. Go slow, and watch your tire and your gauges.
Once you get a good deal of experience filling up your bike tires using a compressor, then you can get a good feel on how fast you can go.
Once your tires are filled up to the right level, then detach the air hose, screw the valve caps back down if you have Presta valves and put the valve caps back on.
If you do feel that you have overinflated your bike tires, then you can easily check and correct this by bleeding some of the air out.
To bleed air out of a Schrader valve, you can push the center pin down to release the air using a flat screwdriver or the tip of your keys. Some tire gauges will also have a tool for this task.
If you have a Presta valve, then screw the valve cap to the open position at the top, and press down to release the excess air. Screw the valve cap back down to a closed position, and put the valve covers back on.
