The Holy Grail (Not Bikes, but Cars, and Not Just Tubes)

Market Prospects of TPU in Bicycle Tire Applications

PUdaily | Updated: April 11, 2024

Whether in terms of weight reduction or rolling resistance, inner tubes are one of the most cost-effective upgradable components on a bicycle. In response to the demands for weight and resistance reduction, TPU has been considered as a material for inner tubes. TPU inner tubes represent a new technological advancement in recent years. In 2020, Schwalbe introduced its Aerothan TPU Tubes, becoming one of the pioneering companies to launch TPU inner tubes. It also marks the official entry of this material into the commercial bicycle sphere.

Currently, the mainstream materials for inner tubes are butyl rubber, latex, and TPU.

Butyl inner tubes are the most widely used standard inner tubes in cycling. Made from elastic polymers, butyl inner tubes offer good stretch and rebound properties and are the most affordable option. Latex inner tubes fall in the mid-range in terms of cost, mostly produced from natural rubber. Latex rubber is more porous than butyl, meaning latex tubes lose air much more quickly. The price of latex tubes is typically 2-3 times that of butyl tubes.

TPU inner tubes are at the cutting edge and also the most expensive. As a flexible plastic, TPU excels in weight reduction. A typical butyl inner tube weighs around 140 grams (actual weight may vary slightly due to size and valve length), while a latex inner tube reduces that weight to approximately 85 grams. As for TPU inner tubes, the weight drops to just 25 grams. This means that the weight difference between two bicycles made of butyl rubber inner tubes and TPU inner tubes can reach up to 230 grams. This is why many professional cyclists opt for TPU inner tubes when competing.

Another obvious difference among different inner tubes is their rolling resistance. It’s found that the rolling resistance of the best butyl inner tubes still consumes about 3 watts more than TPU inner tubes and 4 watts more than latex inner tubes. In long-distance mountain climbing, a bicycle equipped with TPU inner tubes can increase power by 10 watts, equivalent to reducing weight by 2 kilograms.

Another trend nowadays is tubeless tires, which are tires without inner tubes. Compared to traditional clincher tires with inner tubes, tubeless tires have lower rolling resistance and better puncture protection. However, the high maintenance costs, difficulty in component assembly and replacement, and the risk of air leakage or even tire separation still raise concerns.

China’s bicycle output reached around 100 million units in 2023, reflecting a significant growth potential for TPU inner tubes. Furthermore, Aerothan road tires launched by Schwalbe in July 2023, which replace rubber with nylon-coated TPU material in cover tyres, achieve comprehensive upgrade in puncture protection and weight reduction, potentially opening up new applications for TPU in tires.

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