These airless Metl tires are made from nitinol, a shape-memory alloy that ‘stretches like rubber but is strong like titanium.’ Warning: Kickstarter.
The Metl bicycle tire is the first consumer product we’re aware of to use nitinol, a NASA-developed shape-memory alloy made of nickel and titanium that can be trained with heat to remember its shape. Compared with traditional bicycle tires, Metl tires will never go flat and will last a lifetime — at least that’s the promise made by The Smart Tire Company, hailing from Akron, Ohio, which is also home to the Goodyear Tire and Rubber Company.
Just be careful: the tires are being sold via a crowdfunded campaign on Kickstarter and that brings along risk, which I’d rate as high for something as cutting edge as this from a small startup. You’re also looking at a pledge of $500 for a pair of blue or clear Metl tires (weighing 450g with an equivalent size of 700x35c) that are “DIY easy install” onto most common road or gravel bike rims. That’s about 10x the price of good bicycle tires, with prices exceeding $1,300 when opting for a pre-assembled bundle that includes aluminum rims, or $2,300 if you prefer carbon rims.
Here’s a Verge video that provides a deeper dive into nitinol and its NASA origins (and future):
Despite their memory-metal construction, the tires do provide grip thanks to an integrated all-weather tread that offers “medium low” rolling resistance, according to the campaign. The tread is rated for up to 8,000 miles with retreads priced at $10 per tire. The Metl bicycle tires are said to offer a “lightweight, smooth ride, with superior handling and durability” that can also “increase traction” compared to typical air-filled tires.
Estimated delivery of the Metl bicycle tires is listed as June 2024. As of right now, the campaign already has 128 backers, earning triple its goal with 28 days still to go. Stretch goals (if the campaign earns enough) include making wider Metl tires for eBikes and mountain bikes, and more road/gravel sizes and tread patterns.