At $250/tire it needs to ride considerably better than $40 foam inserts.

There should be an hysteresis curve for NiTi material which would give an idea of the energy wasted deforming on smooth or rough surfaces.

The reason pneumatic works so well is that the air in the inflated tire only undergoes small compressions and expansions so little energy ends up as heat.

https://newatlas.com/bicycles/metl-shape-memory-airless-bicycle-tire/

Airless tyres that use an inner skeleton made from a shape-memory alloy – designed to consign punctures to history – are looking for crowdfunding on Kickstarter, with a delivery date pencilled in for next year..

We’ve covered the Metl tyres from The Smart Tire Company on road.cc a couple of times before, but now is the first time you’ve been able to put your money down for them. They also appeared on Shark Tank, a US version of Dragons’ Den, but they failed to secure investment there..

The technology ultimately derives from NASA – it was used for Mars rovers where fixing a flat isn’t an option – and we all know that NASA tech, like anything from F1, is guaranteed to get cyclists excited.

The Metl tyres feature a shape-memory alloy (SMA) called Nitinol, an alloy of nickel and titanium, that’s coiled up inside like a stretched-out Slinky spring. The idea is that the Nitinol allows the tyre to deform and then recover its shape perfectly.

The Smart Tire Company says, “It’s a lightweight, highly flexible ‘superelastic’ metal that stretches like rubber, but is strong like titanium and will always instantly snap back into its original shape.”

The company claims that Nitinol provides the highest energy return of any material used for tyres and leads to low rolling resistance. It also says that Nitinol offers impressive shock absorption and elasticity for a smooth ride, it is lightweight and it’s extremely durable.

The Smart Tire Company says, “Save time and money with zero flats, no air pressure to check, no sealants, no inserts, no foams, no patches, no spares, no expensive replacements, and no more being stuck in the middle of nowhere carrying or walking your bike. No more worries. Just ride.

“That’s the key: new materials unlock our ability to make tyres that are practically indestructible (we even shot a bullet through it and kept riding), more energy efficient, with a smooth ride comparable to any conventional, air-filled tyre. [This is] the first high-performance, non-pneumatic (airless) tyre for cycling that is sure to be a game-changer within the industry.”

Of course, having the metal in contact with the ground wouldn’t work in terms of traction so a “special poly-rubber material” is used over the top. The Smart Tire Company says that this provides “the longest-lasting tread and grip, for all weather conditions” and that the tyre is re-treadable (at estimated costs starting at $10/£8). The translucent sidewalls allow you to see the Nitinol coil inside.

The Smart Tire Company is also keen to shout about the ecological benefits of switching to Metl tyres.

“We are building smarter, more sustainable tyres for the circular economy,” it says. “Many major problems with pneumatic tyres are addressable by our technology, including lower weight, less rubber, fuel efficiency, zero flats, and a significant reduction in waste.

“Developing a longer-lasting tyre that uses 50% less rubber is a critical step in developing a circular economy for transportation.”

The Smart Tire Company is kicking off with a 700C road/gravel tyre that’s available in 32mm, 35mm, and 38mm widths. The 35mm version has a claimed weight of 450g. For comparison, the 700C x 35mm Panaracer GravelKing Plus TLC tyre that we reviewed on road.cc weighed 353g – although with a pneumatic tyre you have to consider the weight of a tubeless valve and sealant or an inner tube too. The Smart Tire Company reckons the tread will last 5,000-8,000km (3,100-5,000 miles).

You need to pledge $500 (about £400) to be in line to receive two Metl tyres with delivery expected in June next year. That’s much more than a standard set of tyres although The Smart Tire Company reckons that, with re-treading, they could last the lifetime of your bike.

Pledging $1,300 (about £1,040) puts you in line for an aluminium wheelset fitted with Metl tyres, while you need to pledge $2,300 (about £1,840) for a carbon wheelset complete with Metl tyres. As we always point out, pledging money on a crowdfunding site isn’t the same as buying through a retailer.

https://road.cc/content/tech-news/no-more-flats-nasa-derived-airless-tyres-hit-kickstarter-303845.

On Saturday, September 16, 2023 at 8:45:26 AM UTC-7, swldx...@gmail..com wrote:
> Airless tyres that use an inner skeleton made from a shape-memory alloy – designed to consign punctures to history – are looking for crowdfunding on Kickstarter, with a delivery date pencilled in for next year.
>
> We’ve covered the Metl tyres from The Smart Tire Company on road.cc a couple of times before, but now is the first time you’ve been able to put your money down for them. They also appeared on Shark Tank, a US version of Dragons’ Den, but they failed to secure investment there.
>
> The technology ultimately derives from NASA – it was used for Mars rovers where fixing a flat isn’t an option – and we all know that NASA tech, like anything from F1, is guaranteed to get cyclists excited.
>
> The Metl tyres feature a shape-memory alloy (SMA) called Nitinol, an alloy of nickel and titanium, that’s coiled up inside like a stretched-out Slinky spring. The idea is that the Nitinol allows the tyre to deform and then recover its shape perfectly.
>
> The Smart Tire Company says, “It’s a lightweight, highly flexible ‘superelastic’ metal that stretches like rubber, but is strong like titanium and will always instantly snap back into its original shape.”
>
> The company claims that Nitinol provides the highest energy return of any material used for tyres and leads to low rolling resistance. It also says that Nitinol offers impressive shock absorption and elasticity for a smooth ride, it is lightweight and it’s extremely durable.
>
> The Smart Tire Company says, “Save time and money with zero flats, no air pressure to check, no sealants, no inserts, no foams, no patches, no spares, no expensive replacements, and no more being stuck in the middle of nowhere carrying or walking your bike. No more worries. Just ride.
>
> “That’s the key: new materials unlock our ability to make tyres that are practically indestructible (we even shot a bullet through it and kept riding), more energy efficient, with a smooth ride comparable to any conventional, air-filled tyre. [This is] the first high-performance, non-pneumatic (airless) tyre for cycling that is sure to be a game-changer within the industry.”
>
> Of course, having the metal in contact with the ground wouldn’t work in terms of traction so a “special poly-rubber material” is used over the top. The Smart Tire Company says that this provides “the longest-lasting tread and grip, for all weather conditions” and that the tyre is re-treadable (at estimated costs starting at $10/£8). The translucent sidewalls allow you to see the Nitinol coil inside.
>
> The Smart Tire Company is also keen to shout about the ecological benefits of switching to Metl tyres.
>
> “We are building smarter, more sustainable tyres for the circular economy,” it says. “Many major problems with pneumatic tyres are addressable by our technology, including lower weight, less rubber, fuel efficiency, zero flats, and a significant reduction in waste.
>
> “Developing a longer-lasting tyre that uses 50% less rubber is a critical step in developing a circular economy for transportation.”
>
> The Smart Tire Company is kicking off with a 700C road/gravel tyre that’s available in 32mm, 35mm, and 38mm widths. The 35mm version has a claimed weight of 450g. For comparison, the 700C x 35mm Panaracer GravelKing Plus TLC tyre that we reviewed on road.cc weighed 353g – although with a pneumatic tyre you have to consider the weight of a tubeless valve and sealant or an inner tube too. The Smart Tire Company reckons the tread will last 5,000-8,000km (3,100-5,000 miles).
>
> You need to pledge $500 (about £400) to be in line to receive two Metl tyres with delivery expected in June next year. That’s much more than a standard set of tyres although The Smart Tire Company reckons that, with re-treading, they could last the lifetime of your bike.
>
> Pledging $1,300 (about £1,040) puts you in line for an aluminium wheelset fitted with Metl tyres, while you need to pledge $2,300 (about £1,840) for a carbon wheelset complete with Metl tyres. As we always point out, pledging money on a crowdfunding site isn’t the same as buying through a retailer.
>
> https://road.cc/content/tech-news/no-more-flats-nasa-derived-airless-tyres-hit-kickstarter-303845.

Need some graphs and numbers to compare it to polymer foam which makes riding on a smooth surface feel like a soggy alfalfa field.