Bicycle Inner Tube Size Conversion Chart (Plus Recommendations)

If you’re looking for a simple guide to inner tubes (with a list of recommended tubes) then you’ve come to the right place.

The sad fact is that inner tube sizing (and tire sizing for that matter) is a dark art.

Over time, different countries and different manufacturers have built up a system that is so complex that probably only 2 or 3 people in the world actually understand it. Whilst I can’t claim to be one of those people, I have attempted to pull together a simple and straightforward guide to show what inner tube I’d recommend for each particular size of tire.

My intention is that you can just click the link, buy the tube, and then forget about the whole sorry mess that is inner tube sizing.

I’ve included a quick guide below to show you how to quickly determine your tire size (and therefore your inner tube size). First, I’ve got the list of tire/tube sizes and my recommended inner tube for each. Below all that I’ve got a little more detail on why tire and tube sizing is so difficult – read this if you dare!

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Inner Tube Chart And Recommendations

Here is the list of tire sizes with my recommendation for the inner tube that you need. If your size isn’t listed, drop me a message and I’ll add it.

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How to determine your tire and tube size

Thankfully, for most modern bikes, this is usually a quick and easy process.

Stand next to your bicycle and crouch right down next to one of the wheels. Take a close look at the sidewall of the tire – this is the strip of rubber which is adjacent to the metal wheel rim and is the part of the tire that doesn’t come into contact with the ground as you cycle. On some bikes, such as beach cruisers, this will be a different color to the rubber that has the knobbly grips on it.

If you look at the rubber surface closely, you’ll see that there are numbers and probably words set into the surface. There might be a tire brand (such as ‘Kenda’) and there should also be a code for the bike tire size.

The tire code might look something like one (or more) of the following:

• 700 x 23c (this is the metric sizing)
• 26 x 1 ¾ (this is the imperial sizing)
• 50-559 (this is the ISO or ETRTO sizing)

Confused? Yes, you should be. Don’t worry though, I’ll keep this really simple. Just take the code that you see, check it against the chart above, and buy the corresponding tube.

I’ve got some more details about what the various numbers mean in a moment but, if you feel your eyes glazing over already, then there’s no need to read it! Just look up your tire number on the chart and you’re away.

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Why is tire and tube sizing so difficult?

The problem is that, historically, there hasn’t been a universal system for tire and tube sizing (even though the ISO/ETRTO system made a valiant attempt to do this, it hasn’t really been taken up across the board). Because there’s been no universal system, lots of countries and manufacturers have created their own system. Most of which are quite different to each other. So we have a metric system using millimeters (which has tire sizing such as “700x23c”) or the imperial system.

Even under the imperial system though things aren’t entirely consistent. For example, you get tires which are listed as “26 x 1 ¾” and tires which are listed as “26 x 1.75”. Bizarrely, these tires are probably not the same size…

Having said all that, a quick explanation as to what the numbers mean is (hopefully) useful.

The first number (such as 700 or 26) is the nominal diameter of the tire, in millimeters or inches respectively.

The second number (such as 23 or 1 ¾ or 1.75) is the tire width, in millimeters or inches or inches.

Sometimes you’ll also see a letter (as in “700x23c”) this “c” was part of the old French system for categorizing tire widths. I have no idea why tire manufactures still show this as it has no relevance whatsoever to modern tires.

When you’re choosing inner tubes it’s useful to know that you have a little leeway in terms of sizing. That’s because, like a kid’s party balloon, the width of the tube varies according to the amount of air you blow into them. As a result, you’ll see tubes listed with a fixed tire diameter and a range of widths. An example would be “700×18-23” which would be a tube that can be used for tires from 700x18c up to 700x23c

It’s also worth taking a quick look at inner tube valves. These are the bit of metal that you fit the pump nozzle to in order to inflate them. Car tires, and many bike tubes, will have a valve known as a Schrader. Bike tubes with a Schrader valve can be inflated with a car tire pump – just be aware that the pressures can be quite different.

Some tubes have a different type of valve, known as a Presta. These are thinner and longer than Schrader valves. If you have a tube with one of these valves, and a pump that is designed for Schrader valves, then you’ll need to buy a little adaptor to pump your tubes up.

With this, you’ll be able to connect your pump nozzle up to both Presta and Schrader valve types. Take a look at the Amazon pictures and you’ll see how easy they are to fit on and use.

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Help! I’ve got a blown tube! What do I do?

First up, don’t panic. With the right equipment and a little know-how, you’ll soon see that tires and tubes are easy to fit and should only take 45mins or so.

The five-step process to fixing a flat tube is:

1. Undo and take off the wheel
2. Remove the tire and tube
3. Find what caused the problem
4. Either fix the tube puncture or change it for a new tube
5. Re-fit the wheel

For a simple guide showing how to do this, take a look at this video.