How To Fill Up Bike Tires

We spend an inordinate amount of time talking about putting air in bike tires. Why, how much, how often, and how to. We do this because, just when we think we have comprehensively covered this topic, we see people riding around on tires as soft as a stomach-sleeper's pillow.

Putting air in your bicycle tires will (1) keep them from getting pinch flats (which should be the only reason anyone would need), (2) help you travel faster and more efficiently, and (3) not seem very hard, or take a long time, once you know how to do it.

We believe there are four basic reasons people fail to regularly fill up their tires.

1. Not knowing that tires need filling in the first place.

2. Not having the right tool for the job.

3. Not knowing how to do it (how to use the pump, how the valves work or being worried about over-inflating the tire and blowing it off the rim)

4. Not having time.

Let's address these reasons one by one.

You don't know your bike tires need filling

You know a flat tire when you see one, but do your tires really need more air if they appear nice and round?

Quite possibly.

Bicycle tires lose a little air all the time, whether you are riding your bike or not. How often you need to refill is mostly dependent on the type of tire, and the optimal recommended pressure. The correct pressure is embossed on the side of the tire and expressed as a range in units of PSI (pounds per square inch), for example 65-95 psi.  You should aim to keep your tires closer to the higher number. If the pressure approaches or falls below the lower number, it's time to refill.

It's worth pointing out that as a general rule, the skinnier the tire, the higher the pressure. So, while a typical wide mountain bike tire may take 45-65 psi, an average urban hybrid tire can take 70-90 psi, a skinny fixie or road bike tire requires 100-120 psi.

You can determine the pressure in your bike tires by using a tire gauge, or by feel. We strongly recommend you get a gauge (or a bicycle pump equipped with one) if your bike sports skinny, high-pressure tires. With such tires, it is nearly impossible to estimate the correct inflation. Most other tires should feel good and firm when you apply strong pressure to the tire with the heel of your hand.  When you sit on the bike, the tire should hold its shape, with only the smallest hint of a bulge at the point of contact with the ground. Any softer, and it's time to refill.

You don't have a pump / Can't find the pump / Your pump is annoying

If you do not have a bicycle pump, you can borrow your neighbor's, take your bike somewhere that has free air (like Cosmic Bikes, if you are on the northwest side of Chicago, or your own friendly neighborhood bike shop), or paid air (like a gas station), or, for less than fifty bucks, you can get a pump! We recommend a bicycle-specific floor pump with a built-in pressure gauge.

BTW, this is a very budget friendly and reliable pump, which —at the onset of the pandemic— we parked outside our shop for general use, and after more than one year it was still going strong, after being exposed to the elements, and hundreds and hundreds of daily uses. That, my friends, is $40 well spent.

Once you have a bicycle pump, keep it in a consistent location, preferably near where you usually store your bicycle. In addition to being much more efficient, this is another advantage of a floor pump over a portable pump that can travel with you from one place to another: you can keep it in a predictable place so it's always at hand to fill up your bike tires.

If the pump you currently own is causing you frustration, it could be because you haven't learned how to use it (if that's the case, see below), or that the pump you have isn't right for your needs. A small emergency pump is exactly that: it's designed to be very portable and used while far away from home. A pump with a nozzle that requires the use of three hands is also less than ideal. Again, for regular at-home maintenance, we recommend a floor pump with a universal-fit head that is easy to apply to the valve, and stays on securely while air is being pumped.

You don't know how to do it / You are intimidated by this / Your bike has weird valves

This is nothing to be ashamed of. Millions of people just like you, regardless of their level of education, political affiliation, age, gender or other factors, know nothing at all about putting air in bicycle tires. Hence, the need for this blog post.

Our bike shop, and most other service-focused establishments, would be delighted to offer you a quick hands-on demonstration (though perhaps not during peak traffic hours mid-summer; aim for first thing in the morning instead). In the meantime, here's a quick tutorial:

The two most common bicycle valves: Presta & Schrader.

Presta valve in closed position.

Open the Schrader valve with a pointy object to release air.

To open a Presta valve turn the tip counterclockwise.

1. Familiarize yourself with the valves on your bike.

2. Please refer to images above for a quick lesson on Schrader and Presta valves. For even more information, we have a separate article dedicated specifically the two types of common bicycle valves. Once you have read this, your weird valves will seem like old friends.

3. BTW, most bicycle-specific pumps already know there are two different types of valves, and can handle them without difficulty. Most floor pumps will have either (1) two separate and marked holes to handle Schrader and Presta valves, or (2) have a "smart" or "universal" head that will work with with whichever valve is inserted.

4. Apply the pump to the valve.

5. Position your bike so it is stable (use a kickstand, a wall or a friend), and rotate the wheel so that the valve is up off the ground. Remove the valve cap. If you have Presta valves (see above), make sure the valve is OPEN before applying the pump nozzle. Push the the nozzle of the pump firmly around the valve, and secure with the built-in lever (usually by flipping out the lever at the pump nozzle so that it's roughly in line with the valve --see image).

6. Begin pumping.

7. If you encounter a lot of resistance, likely the pump head is not on properly, and is actually forcing the valve closed. Remove it from the valve, reposition and try again.

8. Check for gaps.

9. After you’ve put enough air in that the tire begins to look round again, pause and examine both sides of the wheel to make sure the tire is evenly seated, and has not slipped out of the rim and is bulging out at any spot. Also check to make sure that a stretch of inner tube is not caught between the edge of the tire and the rim. If either of the above is the case, disconnect the pump, release some air from the tire by pressing in the valve core (see post on valves, above), and push the edge of the tire or the stray piece of inner tube back into the rim, so that the whole tire is evenly seated inside the rim.

10. Fill to maximum recommended pressure.

11. When everything looks good and even, continue filling up the to recommended pressure (embossed on the sidewall of the tire).

Recommended pressure range embossed on the tire.

Make sure tire or tube don't protrude outside of rim.

Apply pump nozzle by pressing it firmly onto the valve.

Secure nozzle to the valve by flipping the locking lever OUT.

You are running late / Feeling lazy / Will do it next time

We sympathize completely. We've all had these feelings before.

But --believe me-- bike tires can appear nice and round, and actually be quite underinflated. If you ride on them in that condition, you open yourself up to the risk of pinch-flats, one of the most common causes of flat tires. What happens is that when you hit a bump, pothole or curb with an underinflated tire, it will bottom out against this obstacle, and literally pinch two small holes in the inner tube.

So, ask yourself: is it worth getting a flat? No, it is not. So just fill up your bike tires. Do it now.

You're welcome!