Thorn Cycles Forum

Technical => Wheels, Tyres and Brakes => Topic started by: Andre Jute on September 15, 2023, 08:24:07 AM

Title: Everlasting Bicycle Tyres from Shape-Shifting Metal, Anyone?
Post by: Andre Jute on September 15, 2023, 08:24:07 AM: NASA's METL flexible memory-metal material has its first consumer product, bicycle tyres! Available soon! USP (Unique Selling Proposition): They're see-through! And they last for the life of the bicycle! No air required! See:
https://newatlas.com/bicycles/metl-shape-memory-airless-bicycle-tire/

(https://duet-cdn.vox-cdn.com/thumbor/0x0:1586x2054/640x427/filters:focal(939x925:940x926):format(webp)/cdn.vox-cdn.com/uploads/chorus_asset/file/24920809/STC_GreenTire1.png)
See? See-through! Photo credit: Vox

I wonder if they'll be making tights for exhibitionists from METL.

The new venture to produce these tyres is financed by a Kickstarter* so that the experiment is paid for by starry-eyed cyclists who believe in products that last forever. See:
https://www.theverge.com/2023/9/14/23873153/nasa-bike-tire-shape-memory-price-smart-specs

Good luck to the unpaid beta-testers.

Projected initial price about 500 spondulicks per tyre, higher in high-government participation regimes. Claimed weight c16oz or say 450 grammes per tyre.

Andre Jute
*Kickstarter: Perpetual motion machine for raiding the credit cards of gullibles. -- Andre Jute's 21st Century Dictionary of the Truths No One Else Will Tell You.
Title: Re: Everlasting Bicycle Tyres from Shape-Shifting Metal, Anyone?
Post by: PH on September 15, 2023, 09:36:31 AM: Interesting, though the science is a bit beyond me. I once went to a expo at RR Aerospace about turbine blades and how they operate at above their melting point and that left me equally bewildered. As I said in another thread, there's that many attempts at developing airless tyres I wouldn't be surprised if it became a reality at some point, though I'll wait till it's established before parting with any cash.
In this instance, it looks like the equivalent to air pressure is pre set, that's a big restriction even if all else was perfect.
Title: Re: Everlasting Bicycle Tyres from Shape-Shifting Metal, Anyone?
Post by: steve216c on September 16, 2023, 09:36:51 AM: Hmmm, “ The tread is rated for up to 8,000 miles with retreads priced at $10 per tire.“, so they are not entirely everlasting. If I could guarantee a run of good health, I’d need a retread every 18 months. My Marathon plus give me at least double that and maybe a bit more.

Of course rolling comfort and resistance would be key on such a product if it really makes sense. And at that price point, even if they prove superior, they will only appeal to a niche who can afford them rather than become a mass market product.

But how many cheap bikes will be sold this Christmas in Halfords and co. that essentially will have lifetime components simply because their users will hardly use them like the millions of other bikes stuck in sheds across the globe? And each of those bikes will have other components that are also lifetime plastics that will end up in landfills in almost new condition when this unused bikes are upgraded. Future archeological digs will find plenty of lifetime components in the future long after the frames have rusted away…

On the other hand. There is a hub, made in Germany that can last a lifetime, is not crowd funded and has been available from all good bike shops for several years. Any guesses? ::)
Title: Re: Everlasting Bicycle Tyres from Shape-Shifting Metal, Anyone?
Post by: Andre Jute on September 16, 2023, 11:56:02 AM: Quote from: steve216c on September 16, 2023, 09:36:51 AM
Of course rolling comfort and resistance would be key on such a product [even] if it really makes sense.

I would also want to know how much of the "tyre" stays in contact with the road in fast downhill cornering, and the "tyre's" behaviour on slippery grass on the middleman on many of the lanes I ride routinely, a question even with the low pressure Big Apples.

Quote from: steve216c on September 16, 2023, 09:36:51 AM
On the other hand. There is a hub, made in Germany that can last a lifetime, is not crowd funded and has been available from all good bike shops for several years. Any guesses? ::)

Ask me an easy one. Heh-heh.

One of the advantages of backwardness* is that one doesn't become anyone's unpaid beta tester. So I'm happy to be backward in taking up new ideas. In bicycling, I missed out on only one really good idea over the last generation, and that I skipped because I moved directly from Shimano's hub gearboxes to the Rohloff HGB. The good idea I missed out on was the NuVinci CVT gearbox and its automatic option, though as a consolation I did experience Shimano's real Di2 full autobox and advanced adaptive suspension for a couple of years until I went Rohloff.

* Explanation removed because someone dobbed me in to the moderator for it. If you're curious, drop me a private message (in the lefthand column under my image click the speech bubble to message me) and I'll send you the removed paragraph for you to judge for yourself.
Title: Re: Everlasting Bicycle Tyres from Shape-Shifting Metal, Anyone?
Post by: PH on September 16, 2023, 12:51:16 PM: ^^^^
Mods - Could we move who won the war and the trouble with Britain to the Muppets thread where it belongs.
Title: Re: Everlasting Bicycle Tyres from Shape-Shifting Metal, Anyone?
Post by: Andre Jute on September 17, 2023, 10:21:14 AM: Apparently METL is not so new, despite the Kickstarter promoter's huffing and puffing in the article linked above. METL (Martensite Elasticized Tubular Loading -- which describes a function of operation of a superelastic metal rather than a material -- the actual material is called Nitinol for nickel-titanium-[invented at]) was invented by "the Naval Ordnance Laboratory, in 1959 (so, yeah, technically space age, if very Space Age 1.0)." See the article from which that quote comes for much more:
https://www.bicycling.com/news/a35980528/smart-tire-company-airless-alloy-tires/ (https://www.bicycling.com/news/a35980528/smart-tire-company-airless-alloy-tires/)
The immediate focus of the article is the most recent prior attempt to bring METL bicycle tyres to market in 2021, which I presume failed or we would have heard about it by now.

If memory serves, the Nitinol tyres with an off-world track record on various Rovers never went faster than 12mph or possibly even 12kph, so it isn't exactly a performance tyre. In fact, I seem to remember the thing was called a "Crawler" until NASA public relations or a newspaper reporter invented "Rover" as more exciting.

Mmm. I was already skeptical. On the Big Apples I've had two flats in near enough 15 years, both of them the result of over-exuberant riding i.e. avoidable. If I fit these expensive METL tyres and they work, what will I be giving up to assure no flats in the next 15 years? Comfort? Traction/adhesion at speed on poor road surfaces? Braking retardation (braking efficiency is always limited by the friction between the road surface and the tyre)? Above all, will I feel as secure on these tyres as I do on Big Apples, which from my very first ride were clearly superior tyres for my circumstances and riding style?