The average motorist has a lot to keep track of these days. Whether its how much fuel is left in the tank, how much charge is left in the battery, or whether or not the cop behind noticed them checking Twitter, there’s a lot on a driver’s mind. One thing they’re not thinking about is tires, theirs or anyone else’s for that matter. It a testament to the state of tire technology, they just work and for quite a long time before replacements are needed.
There hasn’t been a major shift in the underlying technology for about fifty years. But the times, they are a changing — and new tire technology is claimed to be just around the corner. Several companies are questioning whether the pneumatic tire is the be-all and end all, and futuristic looking prototypes have been spotted at trade shows the world over.
It’s Been A Long Innings For The Pneumatic Tire
Pneumatic tires first came into existence in the 19th century, and were first fitted to an automobile by Andre Michelin in 1895, with mixed results. Over the next few decades, the technology rapidly matured, with advancements coming thick and fast.
Fast forward over 100 years later, and pneumatic tires continue to rule the roost. The last major sweeping technological change was the switch from bias-ply to radial construction, with the vast majority of automakers abandoning the former by the 1970s. In the intervening time, there have been steady, continuous improvements to tire compounds and tread designs, but little that the average consumer would notice on a day to day basis.
The only remaining service task for the pneumatic tire is ensuring it has air in. Failing to do so causes premature wear on the tire and can lead to blowouts. To avoid complication of neglectful car owners, several manufacturers have been developing designs for tires that don’t use air at all.
The Newcomer Is a Return to Spokes
The vast majority of airless designs follow a similar theme. An outer ring is fitted with a rubber tread, which connects to the hub with a series of polymer spokes. The weight of the vehicle hangs from the top of the ring, placing the spokes in tension. Bridgestone and Sumitomo have both displayed prototype designs, but it’s Michelin that have been making the biggest public push for the technology.
Michelin recently announced its new Uptis design which has a chevron shape to the spokes. The company and plans to launch the product in partnership with GM as soon as 2024. It’s been a long road getting to this point, with Michelin first going public with their Tweel prototype way back in 2005. Initial prototypes suffered with noise and vibrations, but were promising enough to get the development ball rolling.
There have been other obscure players, too. Resilient Technologies debuted an airless setup for military applications back at SEMA in 2009, though little has been heard since. Going back even farther, however, is the Martin Elastic tire, developed way back in the 1930s and tested on Jeeps of the era.
Thus far, none of these concepts have made it to the automotive market. To understand why, we should first look at why anyone would want to develop airless tires in the first place.
A Concept That Shows Promise
The benefits of the airless tire have been touted far and wide by manufacturers. There are a number of bountiful fruits that the technology has to offer.
The most obvious is that punctures, flats, and blowouts will become a thing of the past. Not only does this have the direct benefit of reducing inconvenience, but it also means that luggage space is freed up because it will no longer be necessary to carry a spare tire, and a boost to mileage as that dead weight is eliminated. Tire pressure monitoring systems will also no longer be a necessity. Huge numbers of tires are thrown away each year due to this very reason, well before the tread or other components are worn out. Getting rid of this problem promises to improve tire longevity significantly.
One of the main benefits is lateral stability. In standard radial tires, it’s not possible to improve lateral stiffness without affecting other properties of the tire. Stiffening the tire in this way can lead to the tire offering a harsh ride, particularly over bumpy surfaces. However, due to the construction of the airless designs, the tire can be made to be forgiving in the vertical axis, while being stiff from side-to-side. This has the benefit of making handling far more sharp, which is of particular interest for sporting and high-performance applications.
The contact patch of an airless tire is another point of interest. Unlike air-filled tires, which by necessity bulge out at the sides with air pressure, the contact patch of an airless tire can be far more consistent and flat. By having no air, it no longer rests on the driver’s shoulders to ensure their tires are sitting at the correct pressure to maintain the proper contact patch.
Another boon of the technology is wear. Despite tire pressure monitors now being widespread, and manufacturers trying to educate drivers about proper tire rotation practices, very few consumers take good care of their tires. Running under or overinflated can prematurely wear a set of tires, but with airless design, this isn’t an issue. Additionally, manufacturers claim that it should be possible to easily and safely replace the tread on such designs, with little to no degredation in performance. This would have huge sustainability ramifications; current estimates are that 1.5 billion tires are discarded each year. Any improvements in the recyclability of tire components could have a major impact.
There are more fantastical possibilities, too. Having an airless design brings the possibility of perforating the tire to create channels for water to flow away. By no longer requiring the water to be pushed out from under the tire. Developments in this area could greatly reduce the chance of aquaplaning when driving through standing water. Since aquaplaning can lead to total loss of control of a vehicle, any improvements in this space have the potential to save money and lives.
Of course, until the rubber quite literally hits the road, this is all heresay. While Michelin have been shipping Tweel products for several years now, they’re limited to low-speed rugged applications, like skid-steer loaders and ride-on lawnmowers. Getting airless tires ready for the highway is going to take some time yet.
What’s The Big Hold Up?
Despite the concept first hitting the news back in 2005, and successful test runs at Hot Rod Power Tour in 2013, we still haven’t seen these products hitting passenger cars en masse just yet. There are several engineering problems to be solved before airless designs are ready for the mainstream.
One of the major issues that is readily apparent at a glance is the potential for debris to become lodged in the spokes. In order to function properly, the spokes must be able to flex freely, Hard objects could quickly damage the spokes if caught up inside, sand, mud, or snow could clog them, causing the wheels to become unbalanced.
Speed has been a particular sticking point for the Michelin designs, with most of their current Tweel products being limited to low-speed operation. Their upcoming Uptis designs are diverging significantly from their earlier Tweel prototypes in an attempt to better meet the needs of passenger vehicles, which are heavier and travel much faster than UTVs and lawnmowers. Any viable design will have to be able to withstand hours of high-speed highway driving without overheating, delaminating, or otherwise failing — and tire companies have had problems getting it right even with conventional designs.
While an airless tire, by definition, can’t puncture or run flat, it has its own unique set of problems. Spokes can be cut, torn, ripped or otherwise damaged, reducing the life of the tire. Currently, very little data exists on these failures due to the prototype nature of the technology. There’s also the possibility of delamination of the tread and outer ring, and other failures related to the unique construction of the tires. It’s important to solve these problems before the tires are put into service with the general public. To do this requires a great amount of testing, which necessarily takes a great amount of time.
Consumer opinion will likely take some time to come around to the idea, Pneumatic tires have been de rigeur for over a century, and airless designs are a radical departure from what has come before. It will likely take significant effort on the part of manufacturers to help customers grow accustomed to the quirks of the new technology. There will be inherent, unforseen limitations, and the designs may not be suitable to fit to existing vehicles.
It’s unlikely that these issues are unsolvable. However, to overcome these problems, and to take a new design to the point where it is ready to face the wild outside world takes a huge amount of engineering effort. Michelin appears to be leading the field, and have been slowly grinding away on the project since the late 1990s.
While nobody can say if these airless tires will ever take off, I want to see an increasing pace of testing and development than we have observed over the past decade. The technology has matured further with each public prototype that has been revealed. It’s clear that there are significant gains to be had, justifying the continued investment into the concept. I eager to know what comes next, and can’t wait to try out the latest tires on the road.
how tiresome
It does indeed tire me a bit.
My bike tyres are frequently airless.. It does not help with the general effort at all!
Hehe.
It seems it would not be a big deal to vulcanize a small mesh rubber screen covering over the exposed sidewalls keeping snow and debris out while still being totally flexible and not limiting the required movement. This may cause a heating issue i am not aware of but, other than that, I think that would do it. I am looking forward to these being operational and available to the general public. Excellent article…I was wondering what the state of these new designs were.
Great idea. A rubber membrane on the sides to keep dirt out. You can also pressurize the internal cavities ensuring the plastic spokes remain clean and free of debris!
Airless tires all have one problem…a rough and bouncy ride. Acceptable on a skidsteer but a no go for passenger vehicles.
Air trapped in the pockets needs to be able to escape. If the air isn’t able to escape or return fast enough, it’s basically like driving with a flat.
No it doesn’t. Air is not supporting the vehicle. The polymer web is. A membrane simply keeps out debris, and is so stunningly obvious it is borderline brain-dead that no one has used one to shoot down the the #1 failure mode of debris ‘in’ the tire.
I thought the open sides were just for testing!
Those open sides are a terrible idea.
You could call it a “hybrid” tire if there is air trapped in it but does not have static pressure. There are similar tires for RC models. They have a deliberate “puncture” and support the weight of the vehicle by the stiffness of the rubber. But the trapped air gives dynamic spring tension and damping.
Only the removal of water will not be better than with conventional pneumatic tires.
I would think that given the modern self driving etc. That using the brakes’ naturally existing heat in a fashion and with an adaptable material in the spokes’ construction, that a car could be modified or created to use that heat (within reason) to essentially soften the ride if there were issues with bumps and turbulence- this would also serve to melt any and all ice, snow or other water- based items that could impact the balance of the tires at the same time- this would obviously have to be controlled so that the heat doesn’t simply melt the tire spokes, but if it were looked into appropriately and a bit of R&D, and that may solve two problems at once.
In regards to the prior claims that “if it’s mot broken than don’t fix it- try googling “tire dumps” to get an idea of the endless piles and mountains of tires – and particularly in the US, where we do not effectively recycle or cleanly burn them for heat (as they can be burned like coal with little to no air pollution- but until that is implemented, it might be a forward thinking idea to find alternatives to the current tire sourcing and disposal processes.
Hmmm… perhaps put a flexible, protective membrane over the sides of the tires? They’ll look more like the traditional pneumatic ones, but should block debris from getting inside.
It would have to be a very strong membrane or at least serviceable. It’s not uncommon for people to hit curbs with the side of their wheels/tires. This is evident by the condition of many people’s wheels out on the road right now.
Previous iterations of the tire have tried enclosing the tire but depending on whether or not the side membrane was connected to the spokes. So far they introduced problems with additional stresses, friction and decreased flexibility of the tire
To avoid the eventual clogging, would be nice to protect both sides of the tyre with a soft rubber cover. This cover may have small holes to let the air flow freely during the deformation of the wheel.
Until you drive through mud and it hardens inside the tire?
Until you parallel park badly and scrape the soft rubber cover off? Then, even if replaceable you have swapped out checking tire pressure for checking your rubber tire covers.
This problem is not as simple as they make it out to be. If it were so simple, it should already be solved.
Yes, my very first question when seeing this was snow and ice getting into the ribs. I live in a cold climate and if you don’t have hub caps on it’s really easy to get stuff clogged into the recesses of the tire rims. This isn’t a big deal until you get up to high speeds and balance is thrown off.
I can imaging the ribs getting damaged by snowpack and ice build up.
“One of the major issues that is readily apparent at a glance is the potential for debris to become lodged in the spokes. … Spokes can be cut, torn, ripped or otherwise damaged, reducing the life of the tire.”
I was thinking the same thing while looking at the design, but what I don’t see mentioned is why they can’t just cover up the spokes and make it look like a regular tier from the outside? Seems like an obvious easy fix for this issue. Which has me wondering if there is some other reason why it was not done?
Yeah, but how else would you know it’s airless? If you cover the sides, then air gets trapped in and it starts to work like a pneumatic tire again.
But seriously, there is a major flaw with airless tires: pressurized air does not stop acting like a spring when it’s -20 C below, nor does it become soft when it’s +40 above. Air does not creep and become permanently deformed when the car sits for a month, and you can change the air pressure.
The last point is the important one. Tire pressure depends on the load, and different cars have different recommended pressures, even between the front and back wheels, even between the same car depending on the load. For example, my car specifies 2.0 bar and 2.2 bars for heavier loads and for pulling. With airless tires, you have to make tires of different stiffness for every car, and you have to swap tires if you want to load up for a road trip.
+10 – hit the nail on the head – maybe someday, but I’d have a hard time seeing these being reasonably useful in northern US, where -40 through 100F is usual operating temp range. Maybe they can find a material that keeps a similar stiffness over that range, but like you said, even if they could, you couldn’t adjust stiffness on the fly like you can with air for a change in load. Hate to say it, but seems a little bit on the ‘solving a problem that doesn’t exist’ side… Seems like it could be great for off-road, ATV/UTV, etc, but how often is a flat tire really an issue on road vehicles? And trading that issue for how many others that go along with this idea? And even the failure mode – generally with a standard tire you rarely encouter a complete blowout/failure, it’s usually a pressure release with a bit of time to react. Drive tires past when ideal, they’ll start to leak. Drive something like these past useful lifespan, and seems catastrophic failure is a likely failure mode, likely in a high stress situation like taking a corner or something… And yeah – car parked in drifting snow/sleet seems like a tough one – unless sides are covered, and unless as earlier stated, it’s a very tough cover, that has other issues… And if a tough cover, seems like we’re back a bit to ‘what exactly were we trying to solve here?’
Waste.
“Drive tires past when ideal,” and they blow. I experienced it once on the highway: A truck blew it’s tire with a loud bang. Luckily it was not directly beside the open passenger side window but beside the closed rear window. There was quite some debris flying around.
Sleet/snow trapped in those cavities would cause imbalance that can be described only as .. Epic.
Yes, but you could solve the problem a different way by having a smaller “inner tire” which is pneumatic and making the spokes of the airless tire connect to the outer radial surface of that inner tire. That way you could still adjust the load and “air springy-ness” via the inner tire and perhaps help compensate for the issues of extreme temperatures somewhat also. And since the outer part of the tire would be the spoked / airless concept you would still achieve the majority of the benefits of the airless design also.
Another benefit with these new tires is that the police wouldn’t be able to stop you as easily with spike-strip ;-)
I thought the change in pressures was solely to keep the area in contact with the road flat to minimise tyre wear.
There other things that happen too of course…
Pressure too low : soft ride, crap handling, tyres heat up, wear on the sides (edge of tread).
Pressure too high : hard ride, better handling, wear in the center.
With this tyre, the contact area is always flat because of the design.
If the pressure is too high, you get a hard ride but it also starts to bounce more. The tire is a part of the suspension system and if the stiffness is not matched with the rest of the load condition, you get an impedance mismatch between the components and that results in handling issues. If you want to have stiff tires, you also need stiff suspension.
Also, surely the efficiency of these tyres will be horrible!
Rolling resistance is from deforming the rubber which saps kinetic energy from the vehicle by hearing the tyres, same as brakes.
Wow good points you bring up. The fact that the car many times requires different air pressure between front and back and under different loads is important. Regarding the side webbing, they can maybe make it out of a clear rubber composite where we can still see that it’s an airless tyre. And someone mentioned that it should probably not be airtight as to avoid air pockets.
If they can truly be re-treaded, that’s great! Otherwise this is a solution without a problem.
And that ‘one last hurdle’ is not insignificant. You go from screws and sharp objects being dangerous to ALL objects being dangerous and don’t even think about driving through mud.
Yeah, I’d hate to think what some tough branches could do to one of these tires nevermind 4 of them.
Though I don’t see how mud and snow would be more dangerous then say rocks/pebbles/gravel and perhaps even sand since it seems to be that any snow or mud caught between those plastic spokes would get squeezed out when that portion is under compression.
But yeah this sort of design appears to be too vulnerable to damage outside of laboratory conditions.
I wonder…….wouldn’t a simpler solution be to fill a tire with something besides air if you want to avoid a blowout? Like a softer plastic or some form of aerogel.
Then again it might be possible to build this plastic spoke system into a standard tire as long as there’s some sort of “air reservoir” in place to keep the internal gas pressure at normal levels so if a puncture occurs it wont result in a blowout…..
It doesn’t matter if it can be re-treaded, because the polymer spokes too degrade over time. By the time you have to, you should ditch the tire anyways.
Please don’t!
Our ditches have enough trash in them!
B^)
Well, the alternative is throwing it in the Jordan, but that’s less common
Depends how long the spokes last then. They could either recycle the spokes for a few tread lifetimes or design the spokes with the minimal amount of material (minimal cost) for a single tread lifetime
That depends entirely on your use of the car. Usually it’s 30,000 to 50,000 miles, some really high quality ones may go to 80k. The trouble is that the rubber gets hard (the plasticizers evaporate/leech and other chemical changes take place) and the tire loses grip under wet or icy conditions. In the end the rubber either crumbles (summer tires) or becomes hard like soap wheels. This is the point where you would normally re-surface the tire.
If a new tire is kept in a climate controlled environment (on the shop shelf), it keeps for about 10 years. In real conditions, 4-5 years after purchase is a maximum for safety and that gets less if the tire has already sat on the shelf for 3 years or more. In other words, the quality of the rubber degrades pretty much as fast as the treads on the wheel under normal driving.
I hope something similar can be done for motorcycle tires in the near future. It’s scary enough to have a blowout in a car, having a front tire blowout on a motorcycle ruins pants just to think about.
I had one go flat once, not really a “blowout”, but it sure made it harder to steer.
Oh Lewin definitely can spell tyre. I made the call that people used to seeing “tyre” would be more comfortable with the alternative spelling than people used to seeing the word “tire”. Feel free to throw me under the bus (as long as it has soft tyres).
‘e’s ‘strine.
t[iy]res
Would be interesting to see the reaction a police officer has, when he tries to “road spike” one of these tires ;)
Especially, if they put holes in them for water/rain passage.
They’ll just switch from spikes to razorblades…
Fish hooks and chains.
Heat seeking missiles.
The classic “Throw a stick in the spokes”
try road patriot a rocket powered emp device that kills the ecm and the car.
also cars of the future with electric motorized actuators for steering and servo motors driving the other stuff they can take a page from minority report tv show where in one episode the future crimes department took control of the car remotely
So the first thing should be to deactivate all remote data connections to the car. And to EMP harden the electronics.
Read my mind…maybe the focus will shift to other components in the vehicle.
That’s the reason the military likes and supports that ideas and development. In contrast to a private citizen it is accepted that the military develops and uses countermeasures to enemy action.
And it for sure counts as “enemy action” when somebody tries to destroy your tires.
airless tires and fusion power. been hearing both are coming soon for a long while now.
Right!
As a young boy circa 2000, I remember gazing in awe at a popular mechanics magazine cover with a prototype flying care and thinking to myself “Flying cars are just around the corner!”
No one really figured out the energy density problem. Solve that, and you have your flying cars.
I attended a battery seminar last year where Uber made a presentation about plans to roll out electric flying cars…they were more or less pleading to the battery community to solve the problem. It was really eye opening.
What energy density problem? Jet fuel has plenty.
The Moller flying car has a calculated fuel economy of 14 liters of ethanol per 100 km, which isn’t all that bad compared to cars. It’s trivial to load it up with enough fuel for any distance you would want to go in a light aircraft.
Sorry, should have been more specific – electrical energy density. Sure, you could do it with fossil fuels…but that just seems unattractive if you’re going to implement a new method of public transit in 2019.
Here’s the white paper if there’s any interest. They may actually pull this off.
https://www.uber.com/elevate.pdf/
> Sure, you could do it with fossil fuels…but that just seems unattractive
Synthetic fuels are a thing.
The aviation industry is trying hard to solve the problem anyways, because batteries simply do not work for intercontinental flights. Even the best batteries are 10-15 times heavier than fuel, and while jet fuel diminishes as you fly, which improves your fuel economy by reducing mass, batteries don’t. In fact, metal-air batteries that offer the best theoretical energy densities actually get heavier because they pick up oxygen from the air.
Batteries are never going to solve this problem because they simply don’t offer the right properties for the job. The only allure is that you get electricity directly out of them, which you can do from a PEM or SOFC as well, so you can actually make a “battery” that runs on fuel. The only question is what you’re going to use for fuel. It can be anything from liquefied cow farts to moonshine.
Yeah, I’m talking about short haul flight (tens of miles – flying car territory). I completely agree that avgas is gonna be around for a long time to do the long hauls….
> Batteries are never going to solve this problem because they simply don’t offer the right properties
Never is a pretty strong word for hackaday 😜
Even if you give a shit on the environmentalists – ethanol can be produced renewable by fermentation of plant matter.
Just about
as long as we have been hearing that Linux is about to become mainstream :-)
It is mainstream already. Evey phone on the planet is running a variant of Linux.
Nope, not playing.
I think water is still a huge issue. As soon as the tire sinks into the water then those “spokes” turn into paddles. I would think this would create a sudden and large amount of “traction” experienced at the sunken tire and could still result in a total loss of control.
When your tyres are suspended in that deep, you have a problem anyhow
If I drive thorough 10cm of water of course I have to be careful (danger of aquaplaning) but it’s no real problem. The “paddle effect” could even be an advantage in mud.
Could be wrong, but I have a feeling a lot of the images we’re seeing are prototypes with open walls for R&D / performance characterizing. I’d be really surprised if the blades were exposed in production.
If not, parking in a puddle in winter will be interesting.
Especially on a freezing day. :-)
Many LOL’s! ;-)
Re-tyre.
“The average motorist has a lot to keep track of these days. Whether its how much fuel is left in the tank, how much charge is left in the battery, or whether or not the cop behind noticed them checking Twitter, there’s a lot on a driver’s mind. ”
How many payments left before it’s theirs.
I think the tires are only shown open, not always open. Otherwise how would you tell you are seeing an airless tire?
I don’t believe you will buy a tire and see the spooks, unless you cut it open.
If you buy a tyre and see spooks it’s a haunted tyre, probably restless ghosts, they’re very ‘tired’.
Many car companies resolved the spare issue by dumping it completely and leaving current motorists screwed by the roadside when the flat involves sidewall damage. The fun thing is that most “modern” tires end up with sidewall damage as their default failure mode.
Usually because the “lapping” gunk that can be sprayed into tyres can take care of smaller holes.
That has its own set of problems because the Tyre can’t be properly lapped due to the gunk doing too good of a job, even though it’s only considered a temporary measure.
The average person can’t unbolt a wheel torqued to modern specs with the short little “tire iron” that the spare tire kits came with anyway.
IMO, replace your run-flats with regular tires, and carry a patch kit. You’re less likely to end up with sidewall damage, more likely to be able to patch a flat on the side of the road, and if you can’t you’ll have to limp to a garage to buy a new tire at 5mph instead of 50mph. Oh no.
The biggest problem I see with these airless tires is that they seem to require a significant profile. On vehicles with large wheels and rotors, and with low-profile tires, you’re not going to be able to get a wheel small enough to accommodate the extra tire profile.
Yes they can. It doesn’t take much of a kick to loosen the bolts unless they’re thoroughly stuck.
Alloy rims aren’t tightened so hard compared to steel.
I’ve had studs snap before the nut came off. Alloy rims aren’t supposed to be tightened so hard, but that doesn’t stop some people screwing it up.
Also had studs cross threaded by tyre shops because the impact driver just drives the things on anyway, and when you eventually (and inevitably) get a flat, the tyre shop is hundreds of miles away and the mechanic who did it has long left and the tyre shop denies everything and claims you must have wrecked it yourself.
The very afternoon I get home from a tyre shop repair/refit, I manually loosen (with a long pipe sometimes!) the nuts and the retighten them to something reasonable that I can actually undo.
@Fred: I would for sure use a torque wrench for that – a good one. It’s no fun when they loosen up just because you only thought you re-tightened them enough.
And the chance you really have to change the wheel at the roadside is really small. I did it never in 30yrs of driving. Although I had 2 small punctures which lost air during a day.
This is a reply to Martin, alas.
> And the chance you really have to change the wheel at the roadside is really small. I did it never in 30yrs of driving. Although I had 2 small punctures which lost air during a day.
Lol. I’ve been driving 5 years, my wife 10. She’s had 2 punchters herself in that time (i fixed both). We’ve also had a friend have a blow out while doing 70mph. Fortunately for us the lorry driver (HGV) behind us was far enough back, saw it happen and managed to block both lanes (we were in the middle lane at the time) to allow us to pull over onto the hard shoulder.
Amusingly the guy from RAC on the phone suggested we could use some of the Gel in it…. We pointed out the tyre was now spread over 3 lanes of motorway and can he please get a truck out asap.
None of those tyres were in particularly bad condition, and none of us drive like idiots either – maybe it’s just because some UK Roads suck or something, but it happens, a lot more than you’d expect.
I’ve seen many a deformed rim and had to bring out the persuading bar and breakover when shops use the 500-600lb impact on lugs designed for 80-100. That’s even without corrosion. You aren’t getting those off at the side of the road with the included iron.
even with fancy high grade bolts, the torque required to loosen them is nowhere near enough to NOT be overcome by stepping on the the tire wrench…it’s a user problem, not a wrench problem.
If however, the tire shop were the typical dumbasses that didn’t bother with setting their impact gun to the right torque and just jam the nuts/bolts on as hard as possible, the obviously you’re screwed without a proper cheater bar or impact driver. If you see this done to your wheels, never use that shop again. It’s a wheel, not a fancy engine head, where you stretch the bolts by design :P
p.s. threads need to be lubricated. Not only does this provide the correct torque value, it also keeps the metal from rusting
Generally wheel lugs are spec’d to be torqued dry. I’m not really sure why, but it’s pretty much universally true.
Only thing I can figure is that nuts with an enclosed end could have hydraulic effects since excess lube would have to squeeze through the root of the thread.
Must disagree.
Some tyre shops (and you don’t know until you’ve been there and been screwed over) tighten so tight that meter long pipes on the tyre iron are not enough. I’ve had them so tight I’ve bent the tyre iron getting the things off!
Lugstuds and lugnuts: the torque spec is dry. It has to do with how torque on the fastener related to clamping force at the mounting face of the hub/wheel. Lugnut/studs can be easily over torqued, but standing on a 3 meter cheater bar does nothing but bend the bar. This is because the force on said bar is not on-axis of the lugnut/stud. Next time one is too tight, use a 4-way lug wrench. Those apply twisting force properly.
Lubricating them greatly increases the chance of breaking them: You need much less torque to reach the same axial (clamping) force – and after “tight” comes “broken”.
Speak for yourself.
Well here in Britain, where both the pneumatic tyre and the English language were invented, we use the word tyre. :-P
Time to let it go. The language has not belonged to the British since mid 20th century. And ‘modern’ English started before the 18th century via the various colonial influences on the language.
But the advent and rise of North America states (Canada and USA) is what made English the world’s lingua franca. And North America also had/has a profound influence on Spanish. The Spanish spoken in Central and Northern Mexico has become ‘standard’ Spanish. As for the other major language (Mandarin) – not many people attempt it as a second language, and I do not consider it international as ‘standard’ Chinese is based on Beijing Mandarin.
Tire. Airless or otherwise.
Your comment is tiresome.
Besides debris there is the potential of being frozen to the pavement if you park in standing water that then freezes before you move the car.
Not going to be street legal for many EU cars as they have tire pressure monitors which have to be operational if fitted originally. Not really going to work there, is it? Besides that: what about the imbalance in the thing at high speed? I.e. you park in the winder by the side of the road, a lump of ice forms in the lower chambers, you go on the Autobahn and boom, your wheel is shredded. Also, these things are probably heavier then regular tires. So what’s really the need for these things? I have my tires changed winter/summer at the shop, they refill the pressure and I never have to do anything. If one would run flat, the pressure monitor will tell me it’s happening.
Tire pressure monitors can be “fooled”, auto racers have been known to put the monitors in a pressure vessel set to the proper psi. Then they can vary the actual tire pressure for traction.
I’m sure the pressure monitor rule could be worked around if there were a tyre that didn’t need pressure.
You have a good point about water freezing inside the tyre though. Presumably one of the engineering challenges faced by the design teams would be a way to have the tyres eat and excrete ice.
One has to love how the ‘you cannot do that!’ EU bureaucracy has crept into everyday thinking. You better call Brussels first pal!
It’s the euromyth thing, where people claim you can’t do X to rouse rabble. Then it turns out you can and there never was any regulation or rule against it – but everyone still keeps believing that the EU is banning curved bananas etc.
For example, most of the regulations that DO exist are completely voluntary since they have to be ratified by the individual member countries and then the local government is tasked to interpret and adapt the rules into local law. In this process, the governments simply pick whatever they like.
For example, Sweden is supposed to be using the Euro but they never changed their currency. They just won’t – and if a country decides to ignore some regulation like that, there’s very little Brussels can ultimately do about it.
Some shady shops in the US place all four TPMS monitors in the spare tire, then inflate it to whatever PSI they want – light goes out.
Its no different to the situation when companies started releasing electric cars and laws that explicitly mentioned engines had to be updated (e.g. laws for mandatory vehicle inspections that required certain things related to the engine to be tested and passed for the vehicle to be considered road legal). If airless tyres come out and the EU regulators are satisfied they are safe, the law will be changed to allow them to be used (and to not require TPMS)
Lunar rover.
That was a really interesting design. I believe that was a flexible spring steel mesh though.
1/6th Earth gravity also made it easier on them.
Pack in the insides around the spokes with a foam that has been treated with a hydrophobic coating…
Ideally the foam will be one layer of dense foam on the edges to ensure no ingress, a lighter softer foam inside to ensure that anything that is in the tire has limited ability to shift around and damage spokes…
For longevity it would be great if your foam can last as long as your spokes do. Alternately last as long as the tread and be able to replace it at the same time.
Those spokes generate heat as they flex. They have to be ventilated.
Interesting point…
Yeah, we don’t have high temp foams. Certainly not stuff that can take like 150F. Way too many armchair MEs here…
Armchair ME checking in – can you remind me where foam was mentioned in the article as a material choice? Last time I checked, some foams are polymers…but not all polymers are foams.
This is why I wish thermoelectric technology was more advanced. If they could put a heat to electricity converter in there and use it to charge my hybrid’s batteries, that’d solve the problem neatly.
Here I sit wondering.
Wouldn’t it just be easier filling a normal tier with semi soft closed cell foam. Preferably of a type that is flexible and somewhat strong. I don’t see too many downsides.
Though, regardless if it is full of air or not, it doesn’t change one of the main reasons the rubber gets tossed in the bin, and that is wear of the running surface itself.
One could make the rubber stronger, but that increases road wear instead. And it can adversely effect the grip of the wheel and thereby reduce handling as well.
A better solution would be to reduce the wear itself, a simply solution would be to not take the car if other modes of transportation are abundantly available.
Though, best solution I can think of for long distance travel is to simply drive the car onto a train, and have the train take it the majority of the distance. This would allow the driver to not need to pay attention to the road at all, could likely also offer charging of electric cars, potential free WiFi on the train, and faster travel times if it is a long journey. All while not wearing on the rubber at all.
Farmers are known to fill t[iy]res with calcium chloride. It gives added weight without freezing. But it rusts the wheels.
One can also fill it with water and some glycerol.
Then it doesn’t corrode.
Though, still doesn’t stop the rubber from wearing out due to traction alone.
But only farmers want added weight. In a car you want as little unsprung (wheel) mass as possible.
There are foam-filled tires for mowers and skidders. Problem is when it is time to replace the tire, it (and all the foam) has to be cut off the wheel. It’s a huge pain, except for the most rugged applications.
“other modes of transportation” are much less flexible. You have to go/drive to a train station and wait for a train. That is acceptable only for real long distance travel. And in that case it s often more comfortable to take a plane and a rental car.
These ought to be equipped in new cars as the spare.
More likely to be ready to go on the rare occasion they are actually needed, and less prone to deflation and decay than a regular pneumatic spare tyre would be.
And if hung on the rear door of an SUV, less likely to be vandalized by puncturing.
One of those, “I’ll believe it when I see it.” Seems like every 12-18 months stories about these damn tires crop up and nothing ever comes from them.
To everyone who keep suggesting foam filling tires: these exist in the off-road equipment segment, but there are a number of issues with it: it’s somewhat expensive, it makes the wheel assembly significantly heavier, and in some cases, can render the rim unusable one the tire is worn out.
Tweels have their own sets of problems, too. Manufacturer defects can be more problematic, since one broken spoke can render them unsafe to use. They’re also a bit heavier and significantly more expensive than traditional tires due to the wheel hub being integrated. I can’t say that they have better or worse wear characteristics than traditional tires, but the ones I’ve had experience working with are really best suited to environments where the likelihood of punctures is high enough and costly enough in the realm of lost time/revenue that the cost of running a non- or semi-pneumatic tire is offset by the time and expense spent due to frequency of encountering flats.
(I work at an equipment dealership and tweels are options for some of the machines we sell, if anyone is curious.)
+1 I’m in the tire business as well.
I can see a lot of airless tires in all those rental bikes and scooters around here. I suppose the lower maintenance cost is a huge selling point for them.
these are basically glorified runflats. Ive ran runflats at 70mph for a good 45 minutes , the end result wasnt pretty, it looked ok but smelled like I had just don a 100 yard rolling burnout. anyone in the automotive business will happily tell you, rubber aint what it used to be, yes tyres are gripier, but rubber just flat doesn’t last the test if time. I have no idea why, but it just doesn’t.
If these tyres do make out out in public i bet they fatigue like mad, and tbo they are trying to solve a non-problem. whats wrong with pneumatic tyres? yes they will go flat very very rarely, but you swap the spare, run flat, or chuck in the can off goo in the trunk. what do you do if one of these tyres delaminates? given most cars nowadays dont have a spare…. your screwed.
airless tyres exists since 1968 (lunar rover had airless tyres), also bikes, lift trucks …, why takes too many time to get mainstream? why not solid with a new compound? why not hybrid tires (air with internal struct)? maybe tyre industries needs flats tyres to earn more bucks …
It’s the application. Airless tires work great for specific applications. Cars aren’t a good application, because cars go very fast, require cornering, and have people in them; airless tires are uncomfortable because they don’t provide as much cushion, plus they are heavier and will have more spinning momentum at higher speeds. All the other issues like debris entrapment are consequences of applying these wheels when they aren’t the right fit for a job.
How do they plan on helping law enforcement to stop cars with airless tires? Spike strips might not work for these.
Time to reinvent the caltrop…
I would expect a tire company to make a decent product, not one with a deliberate vulnerability. So a tire company should not “plan to help law enforcement” but deliver the best and most reliable product, they can offer (with given properties and price).
Or do you install a deliberately weak entrance door to your house to help the police in raiding it?
Rolling mass and unsprung mass, try again hack of a writer a day
Which is stricly a non issue on 99.999% of cars. Check the massive size of SUV wheels…
Incorrect! suspensions are designed with a specific un-sprung mass in mind, so in order to retrofit these wheels onto an existing vehicle the spring/shock combination would need to be changed as well, otherwise there may be some unintended consequences. SUV suspensions are designed with the weight of the wheels included, to change that weight outside of the design parameters would cause issues in ride and handling. The weight of these wheels also scales with size so on any car it would be heavier than a standard pneumatic tire.
The other issue brought up in the comments is the fact that you cannot change the spring force of the spokes and thus cannot adjust for different weight loads for various cargos
Yeah. I’d be interested to see what the damping of flexing all those spokes does to the fuel mileage.
Air works as a reasonably efficient and predictable spring.
That’s one of the big reasons why other airless tires (foam filled, etc) have been so terrible. Flexing the foam just turns so much energy into heat
Great point. It will affect it.
Downhill mountain bikers sometimes use foam tire inserts. Granted weight isn’t much of an issue for them.
I just hope that this would be a really sturdy tire than what we have today and not worrying if my tire step on a really sharp object,
I would also be a buyer if this really happens but I would invest more on other techy/new intentions for my car.
The whole article and comments that follow underscore the simple effectiveness of current technology. Let’s say you address the ‘big problem’ of debris lodging in the spokes by putting an effective but durable and flexible sidewall … then you have the current version of a tire but you’ve filled the internal space mostly with rubber instead of air. More weight and production cost for what? The tires still won’t last forever and the only benefit seems be to alleviate a puncture. No idea why this is still a project; K.I.S.S.
People are commenting on snow/mud buildup in the tires.
Maybe the holes in the tires can be oriented in a way so that as the tire spins the stuff is ejected out away from the car. I guess this means that the tires won’t be symmetric about a mid-point radial cross sectional plane, so I don’t know how that would affect anything. That combined with a hydrophilic coating in the interstices and the tires would essentially clean themselves.
Hydrophobic. I meant hydrophobic.
I commonly use hydrophilic coatings, so that just popped out.
LOL on how this post about a futuristic tire turned into a peeing contest about are wheel fasteners. Me I’d go with what the vehicle owners manual says.. there was a series in one of the DIY magazines that featured a service station mechanic names Gus. As I recall he taught to brush away an surface rust before mounting wheel, use a torque wrench while tightening the lug nut in the recommended pattern. No mention of lubrication On steel wheels Too much force defeat the purpose why the wheel mounting holes are stamped in the manner they are. Without substantial side walls, such tires are going to be a nightmare.
Yeah, I kind of assumed you’d have to mount them on rubber pads or something.
I wonder how, they would react during winter time. Snow gets trapped. During parking, it freezes up and one or more sections of the tire is solid. You might get up to speed and hurl a piece of ice out…
Air is cheap and lightweight. Increasing unsprung weight is bad.
Mounting these on a conventional wheel presents a problem. Based on my many years of experience as an automotive service tech, I remain skeptical.
Looks great for off-road motorcycle use right now.
On-road motorcycle use, if it makes it through development, would be a great step forward! Right now a front going flat on the road definitely results in going down immediately with zero doubt about it.
For motorcycle use, instead of a spare on group rides they just have a pickup truck following to haul it in for a new tire/repair.
I think the main market will be medium and heavy equipment for construction sites, the shipping industry, but really passenger cars
2005 ?
https://www.google.com/imgres?imgurl=https%3A%2F%2Fairandspace.si.edu%2Fsites%2Fdefault%2Ffiles%2Fimages%2Fcollection-objects%2Frecord-images%2FNASM-A19750830000_PS02.jpg&imgrefurl=https%3A%2F%2Fairandspace.si.edu%2Fcollection-objects%2Fwheel-lunar-rover&docid=UvrHLA_2mYECoM&tbnid=7mmW6fYW4PFvZM%3A&vet=1&w=2000&h=2000&bih=920&biw=1920&ved=0ahUKEwj4oorVntvjAhXVvZ4KHZb-CGkQMwhRKAAwAA&iact=c&ictx=1
Can see the authorities using them, as “sabotage-proof”.
They can run over nails, screws, etc with negligible effect.
Also incidentally I found something interesting. Many tyres fail through simple wear and tear.
Side wall/tread cracking is a biggie however there is no reason why they can’t be refurbished and used for low impact
applications such as robotic delivery vehicles where speed is less of a factor.
Yup.
I followed Some Links [TM] and the only quotable bit I found was “[Uptis] also consumes less energy than the Tweel and offers better dynamic capabilities overall” in [1]. Reading between the lines it seems they rather prefer to compare bad to badder.
To be expected — I can’t imagine that squeezing an elastomer around has less losses than adiabatically compressing air (yes, in conventional tires part of it goes to the rubber too).
I fear this is *not* the technology for current times. Poor Michelin, they started R&D in the wake of the happy 70’s (yes, it was probably more 2000’s, but those C*Os are rather conservative after having slowly climbed corp’s ladder). At that time, if you wasted energy you were successful & cool.
Hopefully those times are over by now.
[1] https://www.carsales.com.au/editorial/details/michelin-uptis-the-air-apparent-118956/
Beware of removing an existing spare tire just to save weight. In case of a crash, modern vehicles are designed to protect the occupants by collapsing in an intentionally directed manner. This includes the transfer of crash energy into and through the spare tire, which is expected to be in place in its factory installed location. Typically the spare is placed at the bottom of the rear trunk, where it helps route rear collision energy down below the passenger compartment.
By removing the spare tire, the crash energy goes into crushing the empty space, which doesn’t absorb nearly as much as it would with the wheel present, allowing the rear car to encroach closer to the passengers.
So the cabin loses a small bit of its crash-worthiness. Is that a big deal? Over the average number of rear-end collisions in a specific car model, it might make a difference in only one or two percent of crashes. Which isn’t much, unless you’re one of the unlucky ones. But it really means you should consider the risks of a crash against the gas saved.
Anyone think about putting a mesh-like material made of a flexible plastic or rubber, possibly neoprene, right over the spokes? A disk like shape that is attached only over the spokes. As the tire is deformed by underlying debris, the mesh should flex as well and simply tighten the exposed space. The way mesh should work if pushed and pulled upon.
Just use a durable breathable fabric to cover the spokes. No stretch requiered. This protects against debris inside the spokes, has minimal interference with air and water flow, is low cost, low weight, doesnt have any effect on the operation of the tire in terms of stifness or flex so long as the fabric isnt held taut, would improve the aerodynamics of the tires spokes slightly by not having them bare. If there was a 5mm lip on the tires away from the spokes and if the fabric was attached there, then you wouldnt have to worry about anything getting caught on the fabric. In order for an object to touch the fabric while moving you would need to hit something with your a car. A $2 piece of fabric is the least of your worries at that point.