Desperate times call for desperate measures, and you may have to make do with a less than ideal bike air pump to meet your needs. For example, you get ready to go to work only to find that your car tire is so low you can't even make it to a gas station for an air compressor. What can you do? You realize you have a bike pump in the garage for the kids' bikes, but you aren't sure if you can get the job done with a bicycle pump. The short answer is, yes. Using an improvised tire inflator is entirely possible. But you may need to take a look at some instructions to use a mini pump properly.
Setting Up Your Car
The first thing to do when inflating a flat tire is to make sure your car is on a clear, flat surface. If your driveway is at a slight angle, this isn't too big of a problem. If there's enough air in the tire to roll it to the flat street, move to a flatter surface before getting out the hand pump. You'll get a more accurate reading from your pressure gauge, and you'll prevent the car from rolling away once the road tire is inflated. Flat surfaces also make it easier to balance the bike air pump you're using.
Once you've got the car in place, remove the tire valve caps. They are so small that they can be very easy to lose. You may want to have a valve cap small container or a plastic bag to put them in so they don't roll away as you use your bike's manual pump.
Do Your Homework
Okay, it's not something you have to know every day, so you probably have to take a careful look. But to fill your tire properly, you have to know the recommended PSI - pounds per square inch of pressure. Generally, there are a few places you can look for this information. Typically, if it's not worn off (and if it is, it's probably time to replace the tires anyway), the information is written on the tire itself, on the rubber, much like the size of the tire.
It may also be on the inside of your door, usually printed on a sticker. If you can't find it there, or if it can't be read, you can check your car's manual. You'll be able to find the manual online if you no longer have a physical copy. Be sure to read carefully, and if you're getting the information from the tires, make sure you check both front and back. Some vehicles have a different tire and pressure requirement for the back tires.
Checking the Pressure
As a responsible driver, you should have a pressure gauge in your vehicle's glove box so that you are always prepared in case of trouble. It's part of a 'standard maintenance' set you should carry with you everywhere you go. To determine how low your tire pressure is, you'll first want to clean any dirt or grime from the tire valve and then follow these simple steps.
Press the opening of the tire gauge to the top of the stem (valve). Push it firmly into the valve until the hiss of escaping air comes to a halt. Then, release.
Most gauges have a slide reader that shoots out the bottom to show what the pressure is. Take a look at the mark that is closest to the end of the tire pressure gauge itself to determine the actual pressure.
Determine how far below the recommended PSI your tire pressure is. If your tire is even 5 PSI below the recommended amount, you should fill it.
As a side note, while you're correcting the air pressure on one of these tires, you should take the time to check them all, since being low on air isn't always visible.
Preparing Your Pump
The basic idea of actually using the pump is simple enough, but there are a couple of things you need to confirm before actually airing up your tire. A bicycle pump is a vital part of any bicycle tool kit and can come with more than one type of valve end - a Schrader valve (also called an American valve) and a Presta valve are both common. Bicycle pumps with a Presta valve have a thin, threaded metal cylinder at the end. These won't work for your car tire. You'll need a Schrader valve, and many pumps with Presta valves also come with Schrader valves, which have threading for a screw-on cap and a small metal pin inside.
Filling the Tire
Attach the bicycle pump valve to the air valve on your tire. You'll hear air escaping until it seals, and that's normal. Then, with the valve in place, raise and lower the pump bar steadily. If you have a foot pump, keep your leg steady as you push air into the road tire. Remember, neither method won't inflate the tire as quickly as an air hose or a regular portable air compressor pump, but it will still get the job done. Stop frequently to measure your tire pressure, since you don't want to overfill the tire. If you haven't reached the optimum pressure level yet, reattach your bicycle pump and start again.
Keep in mind that bicycle pumps are much slower to fill your tire than a powered pump, so it could take some time. You want to at least get within 5 PSI of the recommendation before you try to drive your car. When you're done, replace the valve caps, screwing on tightly so they don't come off.
While it's not the ideal situation, you can improvise when you need to pump up your car tires using a bicycle pump. The important things are to remember the type of valve you need on your pump, measure the pressure, don't overfill or leave the tire too low, and try to have a smooth, flat spot with nothing to interfere before you get started with the process. If you follow these instructions, you can easily pump the air with a little labor - fill a car tire with a bicycle pump. Look for replacement electric pumps when you can, but pat yourself on the back for your hard work and ingenuity!
If you're still queasy about turning bike tire pumps into car tire pumps, take your car for a test ride on the road! If your ride feels less than sturdy, adjust as necessary. Depending on your car's model, it may show a psi bar on the dashboard. Either way, don't take the vehicle anywhere you don't feel comfortable going, no matter how much of a hurry you're in. Your safety is more important than your tire inflation!