Space-age, no-flat tires take one more step for cyclist-kind with updated airless SMART METL tire prototypes that are lighter, cheaper, and more versatile. Developed for NASA Moon & Mars rovers, the same shape-memory nickel-titanium metal mesh promises a more durable tire for bikes that can mimic the comfort & ground-hugging of a pneumatic tire, but without the pesky air inside. Now, a new generation looks more like a tire, and more like something we could see becoming a real replacement for conventional bicycle tires…
SMART airless METL tire prototypes get real

The SMART Tire Company was on Shark Tank over the weekend pitching their latest & greatest version of airless tires – apparently, also to comedian Kevin Hart, who was celebrity guest-Shark. And now, SMART tires look to be much improved and much closer to reality. The latest METL tire prototypes are now 50% lighter than when we caught up with it last spring, plus it now actually incorporates a rubber tread for grip, and is said to be cheaper to make at the same time.
(Note: Just to get the acronyms out of the way, SMART & METL are both abbreviations – for Shape Memory Alloy Radial Technology & Martensite Elasticized Tubular Loading, respectively – referring to the unique properties of the tires NiTinol metal material that allows it to flex and return to shape.)
What’s new & improved?
One of our real first thoughts about the original woven mesh design was how that would translate to grip on various surfaces – from smooth asphalt to irregular gravel to hardpack dirt & mud. Now it seems that the development team behind METL tires has come up with a solution that bonds a more conventional rubber tread atop their unique structure. It is described as using less rubber than a conventional tire, and is designed to be re-treaded when the rubber wears down.
This latest iteration also appears to use do away with the woven metal mesh outer layer that was developed for grip on space rocks, retaining the special phase-changing metal wire coil that provides casing support and allows deflection without air pressure inside. The new tire prototype also now features a closed polyurethane outer sidewall layer to protect the coil and keep out debris.
The redesigned construction means less of the expensive NiTinol metal inside, so the tires will be both 50% lighter and less expensive.