Smart's Airless Tires are Made From Metal & Designed for Mars

Mar 17, 2021 at 6:52
by James Smurthwaite  

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.


153 Comments

  • 196 0
 You could put on your trainer and grate cheese while riding.
  • 19 1
 or tour de france competitors
  • 1 0
 Cheesy
  • 4 0
 Don't want to do any over-seat maneuvers with those tires!
  • 3 0
 The french users have entered the chat.
  • 179 5
 Looks like a Minion
  • 137 0
 It's all fun and games until you run over a pile of dog poop with your mesh tread.
  • 5 1
 ...or a nail getting caught between the threads? But yes, the poop is gross enough to take off a regular tire, this would make it exponentially gross-er
  • 12 0
 @serviceguy: Debris of just the right size will probably also get trapped inside (pine needles come to mind). Getting it out would be interesting.
  • 4 0
 @serviceguy: One of my old buddies would throw away his shoes if he stepped in dog poop.
  • 5 0
 "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."
  • 3 0
 Just burn it off with a blow torch.
  • 5 0
 @iamamodel: You might be onto something there. Flame it off with a weed dragon, then dip in the polymer of your choice. Did you wax your tires today?
  • 123 3
 This will simultaneously the first and last time we hear about this "revolutionary product".
  • 13 0
 It's no Sham-wow...
  • 9 3
 Unlikely. What if something similar was used for an insert/tube replacement. Or just mold tire rubber to it. Flat tires need to go away.
  • 1 0
 Snuggie.
  • 57 1
 Kinda hard to imagine this being applicable on the mountain, but hot dang what a time to be alive
  • 18 0
 I would think these could act like tubes inside of a traditional tire, similar to a moto mousse insert. No flats but also no ability to adjust pressure for grip either.
  • 11 0
 @mgs781HD: Bingo. It'd be annoying (and probably expensive) trying to figure out the right tire construction for your weight...but once you get the right ones, there's a lot of potential there.
  • 1 0
 @mgs781HD: They might have different tires with different levels of stiffness available. There would still be no adjusting on the fly though. I'd imagine these would cost several hundred dollars at least as well.
  • 4 0
 @imnotdanny: Really trying to see the benefit...
  • 3 0
 @imnotdanny: no adjusting on the fly yet super easy to let some air out.
  • 2 1
 @trillot: Durability is the only one I can really think of. Grip probably won't be good, and not being able to change pressure would be really annoying. Also probably they would be really expensive.

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.
  • 10 0
 @mgs781HD: I did my Master's thesis on this stuff.. You could change pressure (i.e. stiffness of the NiTi alloy) by imparting specific heat/electrical cycles. I'm sure that wouldn't be too difficult to add to the system...haha
  • 2 0
 @wheelie7: is there a little hatch to let all the dirt out mid ride???
  • 6 0
 @unrooted: No no, that's how you get that "planted" feel!
  • 2 0
 @wheelie7: cool. So if we bring an oven on wheels (NiTi Alloy, naturally) on a trailer behind us, that should solve the issue of on the fly pressure adjustments?
  • 2 0
 @big-red: Curious if there will be a membrane of sorts on the inside to protect from debris as well. How easy will it be to change between trail conditions. I imagine it'll be better for the road for quite some time before being a truly competitive mtb tire. But hey, would love to see how it shapes up!
  • 2 0
 @unrooted: 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.
  • 4 2
 @short-but-sweet: I have an idea. Lets put a tube inside it so we can adjust the pressure on the fly.


If Specialized has already patented this please don't sue me.
  • 2 0
 @mgs781HD: on point. Nice thing about using these as inserts would be the ability to pretty much shred a tire but still ride out, then swap on another tire. Similarly, you could swap tires based on the season or terrain type.
  • 47 0
 This sparked my Curiosity.
  • 26 0
 That pun is out of this world.
  • 24 0
 your Perseverance is admirable.
  • 19 0
 Nice opportunity for some puns, eh?
  • 3 0
 These puns always keep my spirits high!
  • 3 0
 @shagolagal: My sides are in orbit from these hysterical puns
  • 3 0
 pure Ingenuity for a bunch of punters like us
  • 1 0
 @dwkikuchi: Watney you doing with these puns?
  • 34 0
 Polyurethanium Just like normal polyurethane, but with added 'IUM'.
  • 28 0
 At least 3 times more added science though
  • 3 0
 @pbuser2299: 173% stiffer as well
  • 1 0
 3x as expensive
  • 3 0
 Triple the hyperbole
  • 24 1
 Finally! I'll be able to tackle those tricky, dusty trails on Mars.
  • 26 0
 Olympus Mons is 25000m tall and gravity is about a third of Earth's. The Olympavalance will be the greatest race in the galaxy.
  • 11 0
 @AyJayDoubleyou: Can you image the Rampage lines on Olympus Mons? The reduced gravity could lead to some EPIC gaps, not to mention the number of flips and spins they could do!
  • 15 0
 @Lokirides: This is about the best argument for investment in space exploration I've ever seen.
  • 2 0
 @nzandyb: Pinkbike can do a drop to flat off the top of mountain.
  • 19 1
 Maybe they’ll sponsor my race series, The Lunar Enduro. Coming in 2048...
  • 11 0
 I hear Pole bikes will survive lunar hucks-to-flat.
  • 13 0
 "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."

Oh yeah I forgot that mining and processing Ti and Ni is a totally environmentally friendly process!
  • 6 0
 And what happens to this when the "polyurethanium" coating is worn off? This is only beneficial when it works as metal-only
  • 8 0
 Came here to comment about this.
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.
  • 13 0
 Is it just me or does the fact this company is run by a reality show contestant make this seem even more unlikely to work out?
  • 9 0
 "but the simplicity of rubber and air always seems to win out"

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.
  • 12 1
 what about, mud, dirty and small rocks rattling inside them...will be nice to see them working.
  • 2 0
 It will be coated with rubber
  • 15 1
 @fracasnoxteam:Good idea!. And then we will put in an inner tube filled with air. A groundbreaking invention indeed
  • 1 0
 @petrospit: No thats the point: no air to maintain it's shape
  • 9 4
 OMG, I feel like a kid on Christmas morning; simply CANNOT wait to read the comments on this one...!

[voiceover, in ominous tones]: "Pinkbike Armchair-Enginner Troll Army...attack!"
  • 8 1
 "This exact example in the article wouldn't work off-road and I don't have the mental capacity to imagine how this concept could evolve into something useful on the trail. Also it's just different from what I'm used to. Therefore, this is stupid!"

Something like that?
  • 6 2
 Muc Off and Stans and all other brands will produce and sell chees insted of milk for “tubeless” titanium tires if this is the future in MBT!?

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.
  • 7 0
 Foam insert compatible? lol
  • 3 1
 titanium? in a consumable product? lol can't wait to see the cost of these! how much tread can actually be applied? and can the tread be re-applied or are you stuck paying for another expensive set of mars tires? much questions!
  • 2 0
 $5k per ton is not exactly insane when you think about this kind of application.
That brings the material cost to 2.5$ 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.
  • 2 0
 @sickriderch: Titanium is super difficult to work with as it loves to oxide, so its not about the material cost.
  • 1 0
 @Konyp: right, this is the direction i was leaning. as is proven by the cost of cane creek's eewing cranks...
  • 2 0
 @novajustin @Konyp

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.
  • 8 0
 The tread will be zipper on...duh
  • 1 0
 I'm actually wondering if one could integrate spikes in any tire size with this technology. Would be nice for the ice.
  • 5 0
 I wonder if they'll also produce a chain mail reinforced prophylactic. For when you really want to be safe.
  • 1 0
 I know its all "testing" but they do not look that fast (rolling resistance) sitting on the Felt IA triathlon bike. Maybe when the Polyurethanium coat comes around but why not use a commuter or gravel bike from Felt in the PR.


www.smarttirecompany.com/cycling
  • 3 1
 Doesnt look that fast? How would a tire look fast in a photo? I am confused why they dont show it in motion if it works - surely investors would be more interested in the tech if it was shown working rather than stationary attached to a bike. Nice follow cam of the TT bike out on the roads or something?

The bike chosen for the model was obviously picked to look high tech rather than mundane.
  • 5 0
 Check the history! NASA 1969 moon rover sported metal-mesh tires.
  • 2 0
 Just commented that, it was my first thought too
  • 3 0
 @inked-up-metalhead:

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!
  • 2 0
 Yes but they were spring wheels, these are shape memory alloys.
  • 1 0
 @Konyp:

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
  • 2 0
 @AckshunW: not gonna lie, the space race was of global significance, and I'm interested in all kinds of big engineering projects, and let's face it, they dont/didn't come bigger than the apollo missions.

And Britain in 1969 was just a country of worker strikes, joblessness and incompetent politicians.





Apparently things haven't changed.
  • 2 0
 @Konyp: shape memory alloys? So they flex and return to shape? Kinda like a spring?
  • 1 0
 @inked-up-metalhead: Well, not quite. Look it up, it some very interesting material science. It may be worth your time.
  • 1 0
 Those moon tires were more just regular springs. I'm not sure if this is the exact same material, but they're making these mesh tires for Mars specifically because of the temperature changes. The material deforms to the landscape then when exposed to a certain temperature it goes back to normal. Check this video out: youtu.be/FBaIdvgbBAM.
  • 1 0
 @DylanH93:

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).
  • 5 0
 Tires built for NASA huh?
Sounds affordable.
  • 1 0
 They came up with stealth rubber (5-10 soles) first, so maybe in a few years...? They are probably not very sustainable though.
  • 4 2
 Wait, the lunar rover from the apollo missions had mesh tyres, made of zinc coated piano wire with titanium treads. Has this been forgotten to history? Why did they use solid aluminium, It was only 1971...
  • 1 0
 I was wondering the same thing.
  • 1 0
 The lunar rover had spring wheels, these are shape memory alloys, a pretty cool thing. Some nice explanations here www.nasa.gov/specials/wheels
  • 3 0
 The lunar rover was essentially a papier mache science project largely held together with pencils, lollipop sticks and hot glue. I'm joking of course - it was a plasticine stop motion model. I'm joking of course - it was a full size mock-up in a hollywood stage set. If you pushed the module over it fell over with a window cutout just where buzz was standing. It only made the DVD extras of course.
  • 5 0
 @browner: Jerry Seinfeld: What the hell were they doing with a car on the goddamn Moon? You’re on the Moon already! Isn’t that far enough? There is no more male idea in the history of the universe than: “why don’t we fly up to the Moon and drive around?” That is the essence of male thinking right there.
  • 1 0
 Aluminum would just turn to powder in Mar's Atmosphere!
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?
  • 2 1
 Could it work for MTB? Sure.

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.
  • 2 0
 It will be hard so don't try....
  • 2 0
 @LoganH: in the 1990's, someone built a beryllium bike frame. It was light. It was strong. It was pretty cool. It was $20,000!! It was a technology that couldn't be adapted into a more affordable, mass market product. I'm saying that's what's going on here. This is really cool tech, but unlikely to ever move beyond being cost prohibitive.

Should this technology be developed? Yes. For bikes? No-it'll never scale to mass production/consumption.
  • 1 0
 @wyorider: Sure many products fail but the fact remains that we have done the impossible time and time again. Computers were 10's of thousands of dollars and only available to governments and the largest of corporations, then through development, we now have a computer in the pockets of a large part of the world.

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.
  • 2 0
 @LoganH: The tech exists NOW to make much lighter, better performing bike tires. However, due to materials and manufacturing costs this hasn't happened. Why? Replacing the nylon fibers used to make tires with aramid would drastically raise the cost of bike tires. Would you spend $300 a tire? No, you wouldn't.

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.
  • 3 0
 "Cyclists will not be able to wait to get their hands on these"

I'm trying hard to parse this quote. Will we not be able to wait because they will never be available?
  • 1 0
 How about that: Full Suspension E-bike with magnetic suspension as well as zero friction magnet bearings, cogs, a gearbox, airless NiTinol+ tyres. Oh and an integrated reaction control system with little cold thrusters. Pretty much no air resistance so you better keep the ability to steer in flight while ripping those 50-200m jumps on Mars
  • 3 0
 NiTi is used extensively in dental applications - rotary endodontics and orthodontics especially. cue dentist bike joke in 3... 2... 1...
  • 2 0
 Polyurethanium ~ tire coating, hair gel and topping for your FAVORITE deeeesserts! Guarantied not to rust, bust or collect dust for the 1st 30 ft or 30 seconds you own it or double your money back...
  • 1 0
 I hope their promises come true! After 3 flats in a single month while commuting, I would love these to work. Also, opens the possibility for spikes on road bikes.. Scandinavian problems.
  • 2 0
 You just need better tires..try Schwalbe marathons, available with spokes or not.
  • 3 0
 They're going to want to market in areas with goatheads. People will pay any price to guard against them.
  • 3 0
 Double casing tires and Stans do a perfectly fine job of preventing flats from goatheads and cactus spines.
  • 1 0
 Already plannig for space biking. I like it. Ready to rip on mars, provided elon doesnt blow you into oblivion on launch. Nasa please bring a bike w/these on the Artemis missions.
  • 1 0
 Wow, the thread sounds like my usual negative posts . i'm going to do a 180 and say i'm sucked in by the hype , but will probably become soured when i find out that the price is " out of this world" .
  • 2 0
 Really curious as to why not a single commenter hasn't picked up that his sole item on his resume is winning Survivor. Are we in the plus/minus window for April Fools yet?
  • 4 0
 How's the grip though???
  • 4 0
 Cornering on paved roads? Not great :-)
  • 4 1
 I wander if the weight is still comparable when packed full of mud????
  • 1 0
 I feel like metal tires on pavement would be pretty slick, maybe not the safest thing for a bicycle? Slow moving rovers don't have the same grip requirements as bikes
  • 1 0
 Aaaand I read the rest of it, they'll coat it in rubber. Seems cool to me!
  • 1 0
 All good until you huck onto a nasty rock and ding your tyre and rim at the same time. Permanent deformations from hitting the rim will really make these roll smooth.
  • 2 0
 This will need a lot of salami to run tubeless
  • 2 0
 If its light enough, maybe it could be made in to an mtb insert.
  • 2 0
 BOOTS ON THE MOON...by 2024 !
  • 2 0
 Chainsaw tread would be sweet.
  • 3 0
 Who needs grip!
  • 1 0
 OK, in this case, I will concede that the contact patch surface area is not determined by the PSI.
  • 2 0
 Number of Minions vs 1 NASA tire?
  • 1 0
 They could atleast stick it inside a normal tire, so you get this thing called grip thats kinda usefull.
  • 2 0
 So that’s why people going to Mars is to ride a bike there
  • 2 0
 Definitely a water and dirt collector!
  • 2 0
 It's too early for April Fools...
  • 1 0
 Yoooo! Are we attacked by killer bees?! No dude, that's my Nasa tires, they're noisy.
  • 1 0
 This will be something to follow!
  • 3 1
 Is it April 1st already?
  • 1 0
 Forget mud, once trail poop gets in there it's all over.
  • 6 0
 Nah it'll ripen, then slowly ooze out as little grains of rice and splatter into your face, over time.
  • 1 0
 The skid steer at the jobsite down the street has something like this.
  • 1 0
 Roadies are gonna love the idea of wrapping their wheels in chainmail.
  • 1 0
 Looks like you can just DIY hack that stuff with window screen.
  • 1 0
 Maxxis Apocalypse... Doom days might be near...
  • 1 0
 How do I setup my favourite "pressure"?
  • 1 0
 Rad. I love seeing people think outside the box and try new things.
  • 1 0
 I can’t see these tires gaining much traction
  • 1 0
 if you get junk or dog sht into it that'll throw your balance way off bro
  • 1 0
 There's literally nothing that I want on my bike less than metal tires.
  • 1 0
 The UCI has already banned them
  • 1 0
 Inquiring minds want to know...will they be offered in 26" wheel sizes?
  • 2 2
 Is it April 1st already? WTF!
  • 1 0
 What tyres for Mars?
  • 1 0
 No way.
  • 1 1
 Tyre buzz.....no thanks

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