Are airless, wire-mesh tyres the future for cycling?

Shape memory alloy tyres originally invented for the Mars Rover are being developed for bikes and are hitting the market this year

- Simon Smythe

A NASA-affiliated company set up to develop a new category of tyre could be one small step closer to a giant leap for the future of transportation.

The SMART Tire Company was formed with the aim of commercialising an airless alloy tyre called METL (Martensite Elasticized Tubular Loading) that was originally invented for space exploration. SMART is an acronym for Shape Memory Alloy Radial Technology.

After seven years of development at the NASA Glenn Laboratory, the company says it is expecting to launch its first METL tyre in Q2 of 2023.

"Starting with the extreme capabilities of this Mars-grade technology, we've developed new, patented tyres designed for cycling, automotive, trucking and aerospace applications," the US brand's statement claims.

Existing airless tyres by brands such as Tannus are made of a micro closed-cell polymer resin (MCP) manipulated to make a solid foam-like material. By contrast, the innovation by the NASA Glenn Research Center comprises a "non-pneumatic, compliant tyre utilising shape memory alloys (mainly nickel-titanium alloy nitinol) as loadbearing components."

Shape memory alloys deform and then spring back to their original shape.

The science says they are capable of undergoing "phase transitions at the molecular level with significant reversible strain (up to 10%), an order of magnitude more than ordinary materials, before undergoing permanent deformation."

Poly-rubber tread