The SMART Tire Company (STC) has introduced its METL tyres, which promise to revolutionize the way we ride bicycles. These tyres, made from a shape memory alloy, boast the elasticity of rubber and the strength of titanium.
Originally developed by NASA for its Mars rovers, this airless tyre technology has been adapted for terrestrial use by STC. According to a successful Kickstarter campaign, the METL tyres are designed to provide minimal rolling resistance, smooth rides comparable to pneumatic tyres, and a lifespan that matches the lifetime of your bicycle. Additionally, their sleek design adds a stylish touch to any bike.
The METL tyres have already made waves in the tech community, winning two innovation awards at the Consumer Electronics Show (CES) in Las Vegas. They were honored in two categories: Vehicle Tech & Advanced Mobility and Sustainability, Eco-Design & Smart Energy. This recognition underscores the transformative potential of this technology in the cycling and broader transportation sectors.
Brian Yennie, Co-Founder of STC, explained the strategic decision to launch with bicycle tyres: “We’re building a bicycle tyre first because it allows us to build core capabilities and put an extremely cool product in people’s hands more quickly.” The initial offering includes road and gravel tyres in sizes 700 x 32c, 35c, and 38c, with the 35c model weighing in at 450 grams (16 oz), which is comparable to traditional pneumatic tyres.
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One of the primary motivations behind the introduction of METL tyres is to address the unsustainable nature of the current tyre industry. STC aims to enhance road safety and sustainability with their puncture-less tyres. The company was founded in 2020 as part of the FedTech NASA Startup Program, in collaboration with the NASA Glenn Research Center. Together, they developed the METL tyre under NASA’s Space Act Agreement startup program, employing memory metals designed to withstand extreme space conditions.
The METL tyre’s core technology is based on NASA’s shape memory alloy (SMA) technology. Each tyre features a central spring made from NiTinol, a nickel-titanium alloy known for its elasticity and strength. This spring, which wraps around the tyre like a “slinky,” allows the tyre to deform under pressure and then return to its original shape, providing a comfortable ride similar to traditional pneumatic tyres.
“Shape memory alloys look extremely promising in revolutionizing the entire terrestrial tire industry,” says Santo Padula, a materials science engineer at NASA who helped develop the tire. “And that’s just the tip of the iceberg.”
The METL tyres are designed with removable treads and sidewalls made of poly-rubber, encasing the NiTinol spring. This design uses only half as much rubber as conventional tyres. While the primary tyre can last the lifetime of the bicycle, the tread may need replacing every 5,000 to 8,000 miles (8,047 to 12,875 km). This longevity and durability are game-changers for both cyclists and the tyre industry.
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One of the standout features of METL tyres is their resistance to punctures. In an earlier interview, Yennie highlighted that “without pressurized air inside your tyres, punctures are no longer a concern. Even large tears won’t slow these tyres down: you could stick a kitchen knife right through and keep on riding because it won’t affect the structural integrity of the tyre.”
STC’s innovation could significantly disrupt the $250 billion tyre market. Currently, replacement tyres generate 75 per cent of the tyre industry’s revenue. The United States alone produces over 246 million rubber waste tyres annually. By introducing durable and sustainable METL tyres, STC hopes to reduce this environmental burden while offering cyclists a superior alternative.
