DIY Airless Tires Work Surprisingly Well

Airless tires have been “a few years away” from production for decades now. They’re one of the automotive version of vaporware (at least those meant for passenger vehicles), always on the cusp of being produced but somehow never materializing. They have a number of perks over traditional air-filled tires in that they are immune to flats and punctures, and since there aren’t any airless tires available at the local tire shop, [Driven Media] decided to make and test their own.

The tires are surprisingly inexpensive to make. A few pieces of drainage tubing of varying diameters, cut to short lengths, and then bolted together with off-the-shelf hardware is all it takes, although they note that there was a tremendous amount of hardware needed to fasten all the pipe lengths together. With the structure in place they simply cut a tread off of a traditional tire and wrapped it around each of the four assemblies, then bolted them up to their Caterham street-legal race car for testing.

While the ride quality was notoriously (and unsurprisingly) rough and bumpy, the tires perform admirably under the circumstances and survive being driven fairly aggressively on a closed-circuit race course. For such a low price and simple parts list it’s shocking that a major tire manufacturer like Michelin hasn’t figured out how to successfully bring one to a light passenger car yet.

Thanks to [Itay] for the tip!

47 thoughts on “DIY Airless Tires Work Surprisingly Well

  1. Why have tire manufacturers not figured out how to produce airless tyres? What proportion of tyre replacements are due to causes that would be eliminated by airless tyres? That may be an economic disincentive.
    The photograph with the nail board gives another clue. Spike strips, both fixed and portable, are used to slow down or stop drivers in some locations. What effect would they have on airless tyres? Security disincentive.

        1. Retreads have been a thing for a very long time but they have never caught on for passenger cars and were always notoriously sketchy – a lot of the 4×4 crowd ran remoulds 10+ years ago and they had a variable reputation if used on the road for any distance.

          I suspect the reason we’re not seeing it is purely technical and/or cost issues as with so many of these inventions. There’s a fair uptake in plant machinery & earthmovers, see a good percentage of those running airless nowadays, and I suspect lessons learned will filter through.

        2. It’s not legal for trucks to use retreads on the front steering tires because they are single wheels. If you lose one of two of the dualies in any of the other wheel positions, there’s no danger (to the truck), but if you lose a steering tire, it could be very bad. Because of this, I don’t know that we’d ever see retreads on the single wheel positions of a passenger vehicle.

    1. Because of all the heat produced from the friction, which is a product of the deformation of the inner structure of the tyre. Air is very good at deforming without massive friction, more substantial materials not so much.

    2. Well, first, can these plastic tubes survive repeated stress over 30K miles or whatever the thread life is?
      In hot and cold weather, sun exposure and potholes? Sure, it is super easy to do the 80% of the project like this prototype. It is the last 20% that is really hard, and in this case they will probably never attempt it.

  2. they should have probably used aviation safety wire to keep the fasteners from loosening themselves due to torque and centrifugal force. these things will likely fail catastrophically if they lose too many fasteners.

    1. Looks like they used nylon lock nuts, which are pretty good by themselves. I’d be afraid of shrapnel from lockwire coming loose, but this was on a closed track, so I think that they’re ok!

  3. “The ride was notoriously rough and bumpy”

    I cannot imagine why.Michelin hasn’t fallen all over itself to bring these to the consumer market. ‘Tis a mystery that for the ages

      1. It is a well-known issue for the ‘real thing’, and one of the reason these sort of spring-suspended airless tyres (as opposed to alternate-fill tyres like solid rubber or foam-fill) have only been adopted for very specific applications.

  4. Ah yes, five years hence, that magical time when I’ll be able to drive my hydrogen powered, provided by fusion power, car, on airless tires on plastic wheels.

    But seriously, why so many freaking fasteners, cement could have saved a lot of weight. Also a tire size should have been figured out where they just had to stretch the tread over, no cutting, and I’m sure balancing the darn things wouldn’t have gone amiss.

    These could be immediately useful for robot rover purposes, but I don’t think I wanna drive on them right now.

  5. Airless tires exsists. The reasons that they seems to be non exsitsing is that there are not used so frequently. As a backup they are already in use (just search for “run on flat”).

    The reasons that mostly air inflated tires are used might be
    a) less parts that could break
    b) comfort. The first cars had classic wodden wheels with metallic surfaces. then came solid rubber tires (still used as emergency tires!) and then air inflated tires.

    Just a hint: if you want to avoid the usage of rubbers for tires altogether: during and after war times there were some replacements at least for bike:
    https://de.wikipedia.org/wiki/Fahrradbereifung#Fr%C3%BChe_luftlose_Reifen_und_Notbereifung (sadly on german)

  6. As a slight different angle, airless tires are not infrequently used for lower speed applications where road noise and high speed grip isn’t an issue. Commercial mowers, skit steer loaders, and even some fairly large industrial machines use airless tires, though when they’re anywhere near carrying a heavy load they get very heavy vert fast.

  7. Not sure there’s a massive advantage anyway – it’s not like punctures are a regular occurrence on cars. If they could make them for for 21C road bike tyres, I’m all ears.

      1. Sometimes there’s a bit of debris like a piece of metal stuck in the rubber and it works its way through the metal webbing over time as the tire rolls. I would imagine the same thing can happen with kevlar.

        1. It does. Metal wires from auto tires will slip past a kevlar layer pretty easily. They’re really good about blocking glass though. I ride over broken glass all of the time with no worries. People intentionally smash beer bottles in bike lanes so it’s pretty common, plus I’m nearsighted and it’s hard to spot glass sometimes.

      2. Kevlar layers are super common. I’ve got 3 sets of tires with a kevlar layer. You can also get tires with an extra thick rubber anti-puncture layer or you can install a Mr Tuffy liner. The more protected the tire is, the heavier it gets and the comfort decreases.

  8. The problem with airless tyres has always been friction.

    Tyres usually have a lot of give in them to smooth out the ride.
    That means deforming the inner structure of the tyre, which means a hell of a lot of friction, which means massive amounts of heat. Heat, that will distort, melt and destroy the tyres inner structure pretty quickly unless they come up with some wonder-materials.

    Thus, it’s probably never going to be a successful thing for fast road-going vehicles.

  9. Building them out of many discrete parts makes sense when you are rolling your own (no pun intended) but they would be more likely cast as large pieces so less fastening or adhesives would be needed in the making of them. This strikes me as a good idea, but for the fact it would take years of clever engineering before we see something with the road feel issues worked out. Another issue no one has talked about is that the tires are part of the suspension, so it might make more sense to simply redesign the whole tire-suspension system with a clean slate.

  10. Shocking that they aren’t available yet? What a massive oversimplification of a huge, multi-faceted project.
    Engineering them is one thing, now make them consistently safe, profitable, recyclable, marketable, competitive, comfortable, durable, reliable, etc. etc.

    1. Yes. This!!! God forbit you forget to remove one clump of snow from your wheel before getting on the highway. It sucks. I can only imagine what caked up mud would do, with so much more room for it to get in.

  11. I used to drive an Audi TT roadster that had lovely cast, spoked wheels and very wide tires. I did not have a set of winter wheels so I drove the ones I had all year. In the winter, if I was parked on the street or in an uncovered parking lot, snow would get into the wheels which were just big aluminum cylinders. The weight or the snow/ice would throw off the balance of the wheels and the car would ride like shite until I got the snow/ice out of the wheels by parking overnight in a warm garage.

    Now imagine what’s going to happen to the airless wheels that are wide open on the sides in snow, rain, gravel, mud, etc. They’re never going to be balanced.

    Now you know why airless tires with open sides aren’t “a thing” and never will be.

    1. You can have airless tire in a socket, like winter sockets for usual tires. That’s not a reason when it did not happen yet. The main reason is the noise, the consumption (such tire aren’t very circular compared to a pressure maintained balloon, so the resistance that the support material must present on weight bearing is fighting with the vehicle weight and dynamic thermal properties), comfort, etc… It’s always hard to introduce a competing technology when an established technology is already present in the market. You have to be better in all point if you want your technology to succeed, or at least not worst on the most desired characteristics (like noise and consumption)

      1. The reason for the open structure is to allow air movement to dissipate heat. Otherwise the interior of the tire would start to break apart form getting squished and stretched repeatedly.

        Even in the summer, you don’t want little rocks and sand getting in there for obvious reasons. It can damage the tire, but also get flung out at crazy speeds towards other road users when the wheel is turning.

  12. Kind of obvious that even without the fasteners, you need a lot more matter to make these. So per wheel costs would be higher while their longevity would mean a much slower purchase tempo. Couple that with years of experience with the increasingly rare ‘blowouts’ (I haven’t had one in a decade) and you can only conclude they just don’t make any practical sense. Great for a Moon buggy or Mars rover but very few use-cases in regular life.

  13. I have Michelin tweels on my lawn mower. It would make sense in such off-road environments, if not for the terrible tread. They have very little grip on dry grass, let alone any kind of dew or even just healthy, spring growth. Yet, somehow, if I turn too sharply (it’s a zero-turn), they make “pivot divots”! It’s like the worst of both worlds… If not for the durability, I’d replace them with standard rubber. As it is, I’m trying to come up with some kind of DIY tread enhancement.

  14. Maybe, they are good for non-winter use. But, I see a possible problem during Scandinavian winters : ice getting stuck in them and flung out while driving, causing damages and or excessive vibration during highway driving.

  15. The big gotcha is the lack of reinforcement. Air-suspended tyres look like you’re running on a cushion of air, but really you’re running hung from a loop of steel (or occasionally aramid) cable. The hub hangs from the top of the tread of the tyre by the wire wrapping around between the beads (the ‘short circumference’ of the donut), the hoop of tread transfers that load to the ground, with the wire loops/belts running ‘along’ the tread preventing the tyre from stretching and collapsing. The air pressure keeps the whole assembly in tension (tensairty structure) so those floppy cables can all do their jobs without any compression members. As the tyre rolls, the load is transferred between whatever loop or loops (for bias ply) are over the top of the hub, and there are so many that this transfer is imperceptible.
    The airless tyres in the OP post are instead reliant on compressive loading of the plastic/rubber tubes under the hub. Transfer of load between these occurs in pretty discrete steps, so the vibration is very noticeable. Adding enough discrete elements to smooth out the running ends up with a foam, and all the issues of foam-filled tyres (e.g. lack of lateral stiffness).

    1. The side walls bulge outwards from the air pressure and this keeps them in tension, so the pressure inside the tire does contribute to how it hangs off of the outer hoop as you describe it.

      https://www.ttnews.com/images/DuraShield-Tire-cutaway-twitter.jpg

      The “cushion of air” is there, just not where you’d think it is. Pressing down on the tire causes more pressure, which bulges the sidewalls out more, which increases the centering force on the hub.

    1. Nah, they’re gonna handle like old cross ply tires, you turn, the tread decides to move to the direction you’re pointing the wheel a second or two later, with similar squab on the rear end. Plus we’re not seeing much evidence they stand up to sporty everyday driving, never mind hammer down hijinx. I’d take Z rated runflats plzkthx.

      Though I’d also have to say that if you planned on a high speed chase, you planned wrong.

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