Airless tires are nothing new. We've seen everything from foam to carbon nanotubes attempting to replace the pneumatic design but the simplicity of rubber and air always seems to win out.
Hoping to change all that is Smart Tyre Company who are bringing NASA technology to the bicycle world with a nickel-titanium alloy (also known as NiTinol+) shape memory tire called Metl that they claim "is elastic like rubber yet strong like titanium."
So, where has this technology come from? Well, Mars exploration presented NASA with a problem as it is too cold for traditional rubber tires and the solid aluminium tires used on Curiosity were prone to cracking, so a new solution had to be found. The idea of mesh tires first came with the Spring Tire in the mid-2000s that used coiled steel wires woven into a mesh pattern, however this didn't stand up to the abuse of Mars' rocky surface. It took until 2017, and a serendipitous encounter between Engineer Colin Creager and Materials Scientist Santo Padula, for a solution to be found in shape-memory alloy nickel-titanium, which looks like chainmail but remembers its shape and returns to it after an impact.
Smart have licensed that technology thanks to a Space Act Agreement and are now applying it to a new application, bicycles. They have started with the Metl road cycling tire but claim the material can will be used for mountain bike, gravel bike and road bike applications in the future.
The tire should conform to the ground in a similar fashion to a pneumatic tyre while being immune from punctures and having a much longer lifespan than a rubber tire. Smart are also keen to push the environmental advantages of Metl. They claim that the tire industry produces '50 billion pounds [25 million tonnes] of toxic waste annually' and that using NiTinol+ presents a cleaner alternative.
There's no word on the weight of the tire but Smart claim that it is "competitive with many mainstream alternatives" and that rolling resistance is similar to a pneumatic tire pumped to 100psi. If you're worried about grip, Smart say they will coat the tires, "in a new, formulated rubber-like material, Polyurethanium, for the longest-lasting tread and grip, for all weather conditions", although there are no details on what this actually is or its efficacy.
Earl Cole, former Survivor champion and CEO of The SMART Tire Company, said: "Cyclists will not be able to wait to get their hands on these very cool-looking, space-age Metl tires that don’t go flat. The unique combination of these advanced materials, coupled with a next-generation, eco-friendly design make for a revolutionary product.”
Smart are currently testing the tire with bikes provided by Felt. Eric Sakalowsky, Felt's VP Global Marketing & E-Commerce, said, "The SMART Tire Company’s tire solution shows an exciting new frontier and we’re excited to offer our bikes to support their testing."
Smart are aiming to bring the Metl tires to market in early 2022 but further details such as pricing, tech specs or how much they weigh after a lap on a muddy trail are still to be confirmed. More info, here.
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153 Comments
or this
Although I suppose people could use these like inner tubes? That would solve the issue of grip. Heavy as f*ck though. IMO these seem really unnecessary. The compromises you'd have to make for the benefit of increased durability makes this not seem worth it at all. IDK about road cycling though, maybe this will be good for that.
If Specialized has already patented this please don't sue me.
Oh yeah I forgot that mining and processing Ti and Ni is a totally environmentally friendly process!
So many companies market their stuff with "environment friendly" in it, but with no real data. These 50 billion pounds are probably 99% truck and car tires right? Which afaik are recycled in western countries (yes thermal recycling counts). I really would love to see the environmental impact balance comparing these metal tires with standard maxxis/schwalbe/conti stuff.
Simplicity? The tread-tire-tube(sealant)-valve-rim-air system is simpler than a chunk of foam on a rim wrapped in rubber? I would think it's pneumatic tires' _flexibility_ that lets it remain king, not simplicity.
[voiceover, in ominous tones]: "Pinkbike Armchair-Enginner Troll Army...attack!"
Something like that?
Just put 3kg of swiss ementaler inside and you have punktures free tires for road bike, for MTB use 5,5kg,
With this super sticky chees inside you can lower your tire pressure to just 2,756 PSI, a lot of traction garanteed....
first use on 2023 reverse mullet Session.
That brings the material cost to 2.5$ if you need 500gr of Titanium in it (it's an alloy, so not pure Ti to begin with, and hopefully not 500gr per tire for a road bike..).
The real questions are regarding manufacturing costs and durability.
Well, seems like NASA has figured it out pretty good. The license agreement probably includes manufacturing techniques, otherwise they would not be able to already show off these prototypes.
Also, they do not use pure titanium, rather an alloy that is ca. 50% nickel and is commonly used in medtech applications (according to wikipedia...).
That being said, scaling hardware is definitely not easy, but not impossible.
www.smarttirecompany.com/cycling
The bike chosen for the model was obviously picked to look high tech rather than mundane.
Yes! I opened my mouth as an American and a visitor to the Kennedy space center some years back. I saw the author was British. But you are too! Don’t ask ME to know anything about England in 1969. Impressive sir!
I’m not an expert on the subject, but even though the material is different (but then again they are both metal alloys with spring temper) I’m fairly certain the function between the mars and moon wheels is 99% the same
And Britain in 1969 was just a country of worker strikes, joblessness and incompetent politicians.
Apparently things haven't changed.
Interesting indeed! Though on earth I’m sure they’re not using the temperature- based phase change property. I understand there are two categories of Nitinol. The other alloy group results in just a super springy material (those metal glasses frames that you can wrap around your finger and they spring back are Nitinol).
Sounds affordable.
www.space.com/20813-mars-penis-spirit-rover-tracks.html
Shame these hi tech tyres are almost useless on planet Earth & bikes are almost useless on Mar?
Wonder what they will make roads out off?
Could it provide a comparable price/weight/performance to current tire tech? Nope!! And the inability to change damping (like changing air pressure) would be a serious hurdle to overcome.
So this is neat space-age tech.......best left for space vehicles.
Should this technology be developed? Yes. For bikes? No-it'll never scale to mass production/consumption.
Your last line "So this is neat space-age tech.......best left for space vehicles." implies that if we don't see an immediate consumer value for something it should be left to the fringes. If that were the case we would have no where near the capabilities we have in any realm of our life.
As for the tech you reference, there were several decades where government and large businesses were the drivers of computer technology. Computers had existed and been refined for half a century or so before they became a consumer commodity.
Likewise, this tire technology is cool and merits more development. But........it needs to be developed a lot (likely over a decade or 5) before a commercial application like mountain bike tires will be viable.
I'm trying hard to parse this quote. Will we not be able to wait because they will never be available?