Friday, September 11, 2009

TechTalk: Selecting and Using a Tire Pump

One of the best ways to keep your bike rolling smoothly and reliably is to ensure that your tires are pumped up to the recommended pressure. For the quickest and most efficient performance, you should pump your tires to the maximum pressure indicated on the sidewall of the tire.

There are exceptions to this; when carrying a heavy load, some touring experts recommend dropping the tire pressure a bit for more comfort. The reasons for this and the rules for calculating how much pressure to use can be rather complicated, and are outside the scope of this article.

The other major exception is if you are riding a mountain bike on singletrack mountain bike trails. Most experienced mountain bikers use the minimum recommended pressure in their tires; this provides better traction over rocks, roots, and other common mountain bike trail obstacles.

Other than these two exceptions, using the maximum recommended pressure is a good rule of thumb to live by for the average recreational road and bike path rider.

It's a fact of life that bike tires, even when brand new and/or in good condition, lose air pressure fairly quickly. It's no different than your car tires; they need to have the air topped off occasionally too, just less often, because they hold a much larger volume of air. As a general rule, you should check your bike's tire pressure as part of your normal pre-ride preparation before every ride.

The best way to top off your tire pressure when preparing for a ride is to use a quality bicycle-specific hand-operated floor pump, such as our favorite, the Blackburn Air Tower 2 shown here. This, like most good bike pumps, will work with both types of bicycle inner tube valves (Presta and Schrader). Some pumps have a "dual" head, with two valve holes--a smaller one for Presta valves, and a large one for Schrader valves. Other pumps have a "smart" head, with just a single hole that automatically works with both Presta and Schrader valves. Some older older models may have a "convertible" head, where you have to take it apart and move some pieces around, depending on whether you want to use it with a Presta or Schrader valve.

There is an adapter available that will let you use a Schrader-only pump with a Presta valve. These adapters are inexpensive, but have a number of drawbacks. They are small and easy to lose. They are rather cumbersome and inconvenient to use. Perhaps not least of all, they are considered way too gauche by many experienced cyclists.

Most good floor pumps have a built-in air pressure gauge. This makes it much more convenient when pumping your tires; you can just watch the gauge as you pump, rather than having to alternately switch a separate air pressure gauge on and off of your valve.

Many people have electric air compressors in their garages. These can be useful, but you need to be careful not to over-inflate your tires with them, as some can deliver a large volume of air too quickly for a bike tire. Most compressors will not work with Presta valves, and the time you'll waste fiddling with a Presta adapter is way more than the time it would take to just hook up a good Presta-compatible floor pump. Plus, an electric pump is not very convenient to toss in your back seat if you're heading out in your car to meet friends for a ride.

What makes a good floor pump? Besides having a Presta/Schrader-compatible head and a built-in air pressure gauge, look for one with sturdy construction. Cheaper pumps will be made of more plastic, while the better ones will have more metal. Look for a larger platform on the base, giving you more room to step with your feet, and less chance that the pump will fall over when you set it aside. A pump with a larger barrel will push more air per stroke, meaning you spend a little less time pumping. Some will have the air gauge mounted near the bottom, while others will have the air gauge mounted near the top, making it easier to see, especially for aging eyes like mine. However, if your pump should happen to fall over on the floor, a top-mounted gauge will take a bigger impact compared to a bottom-mounted gauge, and will be more likely to get cracked and damaged.

OK, we've covered every angle of what you need to pump up your tires in the convenience of home; what about when you're stuck with a flat tire out on the road or trail? Every cyclist's mobile tool kit should include some kind of portable tire hand pump that can be carried with you while riding. The shapes and styles of hand pumps are even more varied than floor pumps.

Some hand pumps have a spring-loaded handle that lets you wedge the pump into the inside of your bike frame to carry it while riding. Some purists will say that this type of pump is the only kind that should be referred to as a "frame pump." However, most hand pumps these days come with some kind of bracket that lets you attach it to your bike frame, so the term "frame pump" has come into common use for any type of pump that you can carry on your bike. With the wide variety of frame shapes being made for bikes, especially on full suspension mountain bikes or swoopy-curved carbon road bikes, it's impossible for pump manufacturers to make a "universal" frame pump of the traditional spring-loaded variety that will work on most bikes. So, the spring-loaded type is becoming less and less common.

Like floor pumps, most modern frame pumps will work with both Presta and Schrader valves. The "convertible" type of pump head is still pretty common on many frame pumps, but some are available with a dual head or a smart head. Even if your bike(s) only use one type of valve, it's handy to have a pump compatible with both, in case one of your riding buddies needs to borrow your pump and uses a different valve.

When selecting a frame pump, you have to choose between two competing needs: small size and light weight versus convenience and ease of use. Regardless of where you draw the line in your preferences, any frame pump is meant to just get you going in an emergency. You'll want to check your tire and top it off with a full-size floor pump when you get home, or when you get to the next rest stop if you're on a supported ride.

Some frame pumps have an upper air pressure limit of 120 to 160psi, sufficient for high-performance road racing tires, while others may have a limit of only 80 to 90psi, good enough for hybrid tires, touring tires, and mountain bikes. In any case, you'll find that in actual practice, it tends to be very difficult to get a tire pumped up to the claimed upper limit of the pump. The usual strategy is to get it pumped up enough to get rolling (when your arms get tired), and again, top it off with a full-size floor pump at the next available opportunity.

Some frame pumps have a built-in air pressure gauge, which makes them a little more convenient to use, like the Serfas Power Stick. These gauges tend to be a little less accurate than the gauge on a full-size pump, plus they add to the size and weight of the frame pump.

One note of caution to keep in mind when using a frame pump...while you are pumping the tire, be careful not to move and jar the pump and tire around too much. The movement of the pump on the tire valve might cause you to accidentally rip the valve from the inner tube. Some newer frame pumps (like the Lezyne Pressure Drive) have a small flexible hose to help avoid this problem.

My personal favorite frame pump has always been the Topeak Road Morph G. The "G" is for gauge, meaning it has a built-in air pressure gauge, plus a flexible hose. It also has a fold-out foot peg and handle, so that it becomes what almost looks like a miniature version of a floor pump. Nothing is easier to use when it comes to inflating your tire by hand by the side of the road. The only downside of this particular pump is that it is considerably larger than most other frame pumps.

The last word in quick tire inflation are the devices that use cartridges of compressed carbon dioxide (CO2). These are ideal for racers or any other rider for whom time is of the essence when repairing a flat tire mid-ride. They are easy to use, small and lightweight, and work extremely quickly. The only downside is that you need one whole CO2 cartridge for each full tire inflation. So, if you carry two CO2 cartridges on your ride, and you happen to get a third flat tire, you're stuck. Although, there are dual-duty CO2 pumps available that have a backup hand-pump mechanism. As with regular frame pumps, you'll want to top off your tire with a full-size floor pump as soon as you can. You may even notice that the tire pumped with CO2 loses air even faster than a tire pumped with a normal frame or floor pump. This is because the pure CO2 molecules are smaller, and leak out of the inner tube faster than the mixed molecules of regular air. When you do have access to a floor pump, it's best to open your valve and let out ALL of the CO2, and re-pump your tire completely with normal air.

Our favorite CO2 pump is the Planet Bike Red Zeppelin Inflator Head. Here's a brief how-to video to show you how quick and easy it is to use:


  1. Aw, crap! This information comes to me a day too late, after I've ordered a Park Tools frame pump (the traditional kind) for my Surly. ARRGG! I probably should have bought the Topeak Road Morph. I have one but the mount doesnt fit beneath the fancy-smancy water bottle cages I used... (Buyer's remorse!)

  2. Two suggestions for using your Topeak pump: 1) Use the zip ties that came with it (we have extras if you need them) to mount it on the bottom side of your top tube. 2) Use the zip ties to mount it on the side of your seat tube--put it on the left side so it won't interfere with your front derailleur, and angle it back a bit so your crank arm (and left foot) won't bang into it.

  3. Actually, my Topeak had a different mount without zip ties that I lost, so I had it rigged on my hybrid with a different mount from another pump that is secured under the water bottle cage. I tried originally to get a replacement mount, but it didnt work with my pump... my Topeak is at least five years old and I guess they dont make them the same way now or something...

  4. Oh, okay, I got ya. My Road Morph is also the older model (bought in 2004) that has a different bracket than the one it comes with now. The barrel on the newer one is a little narrower. Scavenging a bottle cage bracket from another pump, if you can find one with the right size claws, is another good solution #3.