For the past roughly 130 years, bicycle tubes have been produced predominantly from butyl. The black-gray butyl tube was virtually inescapable — with the exception of a few racers who rode latex tubes. But a new era is approaching. Butyl is being replaced by TPU. Because TPU — Thermoplastic Polyurethane — has many advantages over conventional tube materials. 

The advantages of TPU over butyl: 

• Lighter weight 
• Functional at lower tire pressures 
• Better flat protection (against punctures and in most cases pinch flats as well) 
• Lower rolling resistance 
• Smaller packed size; ideal as a spare tube 
• Less air loss 
• More sustainable 

If you're interested in an AERON/TPU tube, you'll quickly discover on the AERON/TPU website that there are different models for different riding applications. If you ride hard or compete in races, for example, you'll find very lightweight tubes with low rolling resistance. If, on the other hand, you're planning longer bikepacking tours or simply want more flat protection on your everyday training rides, you should opt for a somewhat more robust model.

Once you've settled on a particular type — for gravel riders, that's the AERON/TPU CX/Gravel category — all you need to focus on is the correct size and width, as well as the right valve length. AERON/TPU offers Presta valves (SV) in 42 and 65 millimeter lengths. How to find the right dimensions for your gravel tube is explained in our article "Finding the Right Bicycle Tube Size" (LINK). 

Overall, here are the key factors to consider when buying an AERON/TPU tube: 

• Correct size, specified in inches or millimeters (LINK) 
• Right valve type and valve length (LINK) 
• Varying weight options 
• The appropriate level of puncture protection 
• Varying performance in terms of rolling resistance

Ultimately, only you can decide which tube from the AERON/TPU CX/Gravel series is the best fit for you. At AERON/TPU you'll find gravel bike tubes that are extremely fast and lightweight, and equally you'll find products that offer greater flat protection. Or consider this scenario: you only need the tube as a spare for emergencies. In that case, even a very lightweight tube would do the job — one that folds down so compactly it takes up minimal space in your jersey pocket.

No — at least not if by "tubed" we mean not a butyl tube, but a TPU tube, or better yet an AERON/TPU tube. TPU tubes, much like tubeless systems, can be run at low tire pressures. A very lightweight TPU tube comes close to a tubeless system in terms of rolling resistance. The trade-off is that a very lightweight TPU tube offers slightly less flat protection than a tubeless setup with sealant. That said, AERON/TPU Airtubes (LINK) are available in every configuration — light, ultralight, very high puncture protection, standard puncture protection (still better than butyl tubes), in nearly every tire width, and for every riding application. So you get to decide for yourself just how close to a tubeless system you want your tube's performance to be.

First and foremost, it's the material itself, which is more resistant than butyl. Even the lightest AERON/TPU tube offers the same level of flat protection as a butyl bicycle tube. But with TPU tubes, both the material thickness and the number of layers can be varied almost at will. That means there are AERON/TPU bicycle tubes that are several times more flat-resistant than butyl tubes — while still being lighter and more compact, and offering lower rolling resistance.