Why do my bicycle tires keep losing air? (This is completely normal)

Each time I fill my bike with air, after a long ride, I always have to refill it again. At first, I thought I just bought the wrong tube from the wrong shop, and then I came to understand that this is completely normal. The fact is that latex tubes are not completely airtight and will lose some air after each ride and over time. Why do my bicycle tires keep losing air? There are different reasons why.

Note: If your tire keeps going flat, read our guide for why your tire keeps going flat, here. If you want to learn more about why your tire is slowly leaking air over time then read on. 

In this post, you will learn about why your tire is slowly leaking air. You will also learn about how much air they tend to leak over a certain amount of time and exactly how fast they will leak their air.

Why do my bicycle tires keep losing air?

Rubber innertubes are not air tight and naturally lose some air over time. If you are like me and don’t like pumping with a hand pump, you may want to opt for either a stable foot pump or an electric pump. I like both of these in case you are looking around.

• Electric pump: I am really happy with this pump. IU went through two others before finding this. The reason why the other two were not a fit was because one overheated, and the other the motor simply stopped working. That may have been because I chose the lowest price point initially. The reason why I am happy with the electric pump is because I simply don’t have to think when I am pumping my bike. I turn the bike on, and it starts. Once the tube is filled to the preset amount, it will stop. My one concern is noise. It is not quiet at all. But, that is because it’s an air pump. I use it in the house and don’t face any trouble. The only air pump that is quiet is a hand pump.
• Foot pump: The reason why I like having this on hand is if I am taking my bike out for a ride and I am not sure how many days I will be gone. It’s easier to put in the back of my car and it’s very stable. It is also a tad lower of a price point than an electric pump. It balances well and is much easier to use than a hand pump. There aren’t a ton of differences between standing pumps though, and a standard non-branded pump works as well.

Do innertubes deflate over time?

Yes, innertubes deflate over time. When I go for a ride, of about 40 miles, I will typically come back with my tube about 10 or slightly more lower. When I take the bike back out a couple of days afterwards, it will be at about 80 psi typically after starting at 100 psi.

How fast do latex tubes lose air?

Latex tubes tend to lose air at about 1% per hour. Newer tubes have been known to hold air about twice as long as this. There are no tubes available that hold air infinitely, though tubeless tires sets have been known to hold air a lot longer than standard innertubes.

Conclusion

Why do my bicycle tires keep losing air? They lose air because it is natural. At about 1% rate per hour, innertubes will always come back from a ride with a slightly lower psi than normal. A 30-40 mile ride will come back with 10-20 psi lower if you begin at 100 psi to start with. Longer rides, and changes in elevation will make that effect swing higher or lower depending. All in all, it is completely normal for your innertube to be lower in pressure over time. If your tire is going flat, then see this guide.