When you’re out enjoying a ride, nothing ruins the experience like a puncture. That’s why having a spare inner tube is essential. But how do you know what size of inner tube do I need? This guide gives you a quick way to understand exactly what you need to get the right fit the first time. Whether you ride a road bike, mountain bike, or BMX, the basics of cycling stay the same. Knowing your tube sizes is one of the key fundamentals, and once you get it right, it stays with you for life. So, grab a brew, relax, and read on!
What is an inner tube?
A conventional clincher tire setup relies on an inner tube to hold air, as the bead on each side of the tire locks onto the rim when inflated but doesn’t form an airtight seal. The inner tube, which sits inside the tire, has a valve that keeps it pumped up. Most tubes use either a Presta or Schrader valve, so choosing the right valve type for your bike’s wheels is essential. Once fitted, the valve pokes out through a hole in the wheel’s rim, providing access to inflate the tube when needed.
How would I choose the best inner tube for my tires?
Selecting the right tube is important to ensure a proper fit for your tire and to avoid issues like overstretching or pinching, which can cause punctures. The material should be appropriate for your style of riding, whether you’re into competitive road racing, a time trial, or tackling downhill mountain biking. If speed is your goal, reducing weight can offer a performance advantage, while for rough terrains, protection against punctures should be the highest priority.
what size of inner tube do i need
When replacing an inner tube, the first step is knowing the correct size for your bike. Different wheel sizes exist for road, MTB, touring, and children’s bikes, with MTB wheels further categorized into 26 inches, 27.5 inches, and 29 inches. The best way to find the right fit is by checking the tires, as they follow the European Tyre and Rim Technical Organisation (ETRTO) system, which displays measurements like 622 x nn where the nn value represents the tire width. Some tires use the same notation as 700 x nn, making it essential to check the tire wall as the first place to confirm the right size.
Once you determine the correct size, you’ll notice that tubes are often labeled with a range, such as 700 x 20-28c, meaning they fit tires between 20 and 28c. Similarly, an inner tube may be marked as 26 x 1.95-2.125″, which means it is intended for a 26-inch tire with a width between 1.95 inches and 2.125 inches. Another example is 700 x 18-23c, which may seem less obvious, but 700c is the standard size for Road, Cyclocross, Adventure Road, and Hybrid bike wheels, while the range numbers relate to millimeters, meaning the tire width can be 18mm-23mm.
Many road tires today measure 25mm, while Cyclocross, Touring, and Hybrid bike wheels may use widths up to 36mm. To avoid issues, always carry an appropriate-width tube for your tire to ensure a perfect fit. By understanding these size markings and how they work, you can confidently select the right size inner tubes for your bike and enjoy a smooth ride.
Related: what does 700c mean for a bike?
Common inner tube sizes
Once you’ve selected a brand, you should look at the possibilities it offers because inner tube sizes differ by manufacturer.
Usually, they will offer choices like the ones below.
Inner tube size chart
| Inner Tube Sizes for 700c Wheels | Common Use |
|---|
| 700 × 20–25mm | Traditional road bikes with 20 to 25mm tires |
| 700 × 25–32mm | Road bikes with 25 to 32mm tires |
| 700 × 28–37mm | Road, cyclocross, gravel, and hybrid bikes with 28 to 37mm tires |
| 700 × 32–47mm | Road, cyclocross, gravel, and hybrid bikes with 32 to 47mm tires |
| Inner Tube Sizes for 26in, 27.5in (650b), 29in Wheels | Common Use |
|---|
| Up to 2 in. width | Narrow, old-school MTB tires |
| 2–2.3in | Typical XC (cross-country) MTB tires |
| 2.3–2.6in | Trail, enduro, all-rounder MTB tires |
| 2.6–3.0in | Plus-sized MTB tires |
| Over 3.0in | Fat bike MTB tires |
Road, gravel, cyclocross and hybrid (commuter) inner tubes for 700c wheels
Choosing the right inner tube for your 700c wheels depends on your bike type and tyre width. Below is a guide to help you pick the correct size for your road, gravel, cyclocross, or hybrid bike.
- 700 × 20–25mm: Best for traditional road bikes with 20 to 25mm tires.
- 700 × 25–32mm: Suitable for road bikes with 25 to 32mm tires.
- 700 × 28–37mm: Designed for road, cyclocross, gravel, and hybrid bikes using 28 to 37mm tires.
- 700 × 32–47mm: Fits cyclocross, gravel, and hybrid bikes with 32 to 47mm tires.
Mountain bike inner tubes for 26in, 27.5in (or 650b), 29in diameter wheels
Regardless of whether your bike has 26-, 27-, or 29-inch wheels, the following sizes are typical for mountain bike tires.
Although the sizes of 650b gravel and mountain bike tires somewhat overlap, gravel tires are typically offered in metric sizes, as stated in the preceding section.
- Up to 2in width: Best for narrow, old-school MTB tires.
- 2–2.3in: Suitable for typical XC (cross-country) MTB tires.
- 2.3–2.6in: Designed for trail, enduro, and all-rounder MTB tires.
- 2.6–3.0in: Fits plus-sized MTB tires for more grip and comfort.
- Over 3.0in: Perfect for fat bike MTB tires, offering maximum stability.
What Are The Different Valve Types?
What are Schrader Valves?
Many bikes with lower pressure tires, like kids’ bikes and mountain bikes, use Schrader valves, which are the same as those on motor vehicle tires and often called car-type valves. These valves have a core that is sprung loaded, with a central pin that can be depressed using a narrow object to release air from the tube. The spring mechanism keeps the valve closed when not in use. If you enjoy fast, downhill riding, some tubes are designed for impacts, protecting against slamming into rocks and obstacles.
Related: How Much Does a BMX Bike Cost?
What are Presta Valves?
Presta valves have a slimmer stem and are often threaded to fit a locking ring, which helps hold them tight in the rim drilling. These valves are common in higher pressure tubes, especially on a road bike. To inflate or deflate, the top section must be unscrewed, allowing the core to be free to move so the valve can open and close. In a high-pressure valve, the air pressure itself shuts the valve, and closing the top section keeps it shut for a secure seal.
What is a Dunlop Valve?
The Dunlop valve, also called Woods, is a variation of the pneumatic valve that is rarely used on modern bikes but was once very popular. It looks like a cross between the Schrader and Presta valves, with a wider lower section similar to the Schrader, a collar, and a narrow top section like the Presta. Since the rim drilling is the same for Woods and Schrader, it is easy to replace older tubes with a modern variety.
How can I choose the right valve length?
When selecting Presta inner tubes, it is important to check for different valve lengths to ensure they are appropriate for deep section rim profiles. If your bike has deep section rims, the valve should be long enough to extend through the rim hole, leaving enough valve stem visible to fit the pump securely. If the valve is too short, valve extenders can be purchased to make a shorter valve work. It’s also a good idea to carry an emergency spare because some tubes require a longer valve.
Material
What are Butyl rubber tubes?
Butyl rubber is the industry standard for common replacement inner tubes because it is relatively cheap and readily available. This product is strong and resistant, making it a reliable choice for most riders. For those looking for weight savings, there are lightweight versions available, such as the Specialized Turbo and Continental Supersonic tubes, which are popular versions among cyclists who want high performance.
Related: How Are Bike Frame Sizes Measured
What are the differences between Latex and Butyl rubber tubes?
Latex rubber tubes offer enhanced handling because they are more flexible than traditional butyl rubber. They adapt quickly to tires as they are changing shape during cornering or absorbing impacts. With a thinner wall, they provide obvious weight savings and have been proven in multiple tests to deliver lower rolling resistance, making them faster compared to standard tubes.
Are there any disadvantages of Latex rubber tubes?
While Latex rubber has its advantages, it is important to recognize its flaws. It reacts badly when in contact with oils and greases, so it must be handled carefully in the workshop. Since it is gas permeable, latex rubber tubes do not hold air for long like butyl based tubes and require more frequent inflation. They are also fairly fragile, making them easy to tear when inserting. However, because they are faster and lighter, they are worth the investment for competitive riders.
What can I use for puncture protection?
Using sealant is a suitable way to protect inner tubes with removal cores. By pouring it inside, the sealant can quickly seal small holes by drying and forming a clot when it comes into contact with the air. This helps easily fix the type of holes caused by road debris or thorns. Puncture protection is incredibly useful for commuting and mountain biking, ensuring a smoother and worry-free ride.
What about TPU tubes?
In recent years, Thermoplastic Polyurethane (TPU) tubes have become more popular because they are lightweight and have a small pack size. They share characteristics of both rubber and plastic while offering the least rolling resistance when compared to butyl and latex tubes. Many riders choose them for their efficiency, and brands like Tubolito sells lighter, flat-resistant, and compact alternatives to a standard butyl tube. Similarly, Schwalbe produces Aerothan tubes, which make similar claims about durability and performance.
Although TPU tubes are often an expensive option, they can suit riders who prioritize weight reduction. They are ideal for the weight weenie who wants to save space or reduce weight, making them a great spare to carry in case of emergencies. Their robust design makes them stronger than latex, offering a balance between reliability and lightweight performance.
Related: How to Size a Road Bike
Inner tube valve lengths
Because bike wheels vary in depth, Presta valves are available in a variety of lengths. Typical valve lengths consist of:
- 32mm: The standard size for shallow rims with an ~20mm depth.
- 40mm: A slightly longer option, common for mid-depth rims around ~25mm.
- 48mm: Used for mid-depth rims with an ~30mm profile.
- 60mm: Needed for deeper rims between ~40–50mm.
- 80mm: Used for deep-section aero wheels with ~60mm or deeper rims.
For deeper section rims, it is important to select a valve that is long enough to protrude through the rim and allow you to attach a pump easily. Many riders have experienced going on rides, getting a flat, and realizing their spare inner tube kept in a saddlebag by default did not have the correct valve length for their wheels. If this happens while riding, carrying patches can help fix a punctured tube as a temporary solution. Most Presta valve inner tubes come in a range of valve lengths, with some makers offering sizes up to 80mm.
There is no harm in using a longer than needed valve, though it may look odd on shallow wheels. If your rims are deeper than the longest valve available, you can buy valve extenders to add length. These come in a range of lengths and screw onto the top of the existing valve. Some extenders are hollow tubes, while others include an additional valve at the top, which requires you to remove the valve core from your inner tube before screwing on the extender.
The former type is simpler to use but creates a dead space, making inflation harder. The latter requires a fully airtight seal at the inner tube’s valve stem to prevent the tube from leaking air. Another issue to watch for is valve rattle, which can be an annoyance but not a serious problem. This can be stopped by taping around where the valve protrudes from the wheel rim, a classic trick often used by pro team mechanics.
What about tubeless?
If dealing with inner tubes feels like hard work, you might prefer a tubeless setup. Many rims and tires are now tubeless compatible, giving riders the option to go tubeless. To recap, a tubeless setup removes the need for a tube since the tire forms an airtight seal with the rim, much like a car tire. Sealant is added during installation to fill small cuts that could otherwise cause a flat.
With a tubeless setup, riders experience fewer punctures and can run tyres at a lower pressure, reducing the risk of pinching the tube while potentially improving both comfort and grip.
However, setting up tubeless road tires can be tricky, as achieving an airtight seal may take effort. There’s also the cost of upgrading your setup, which some riders find expensive.
