[HN Gopher] Michelin Airless
___________________________________________________________________
Michelin Airless
Author : belter
Score : 323 points
Date : 2021-10-14 14:36 UTC (8 hours ago)
(HTM) web link (www.michelin.com)
(TXT) w3m dump (www.michelin.com)
| tynpeddler wrote:
| Cool stuff. I hope they make it onto the road. What was really
| interesting to me is that the page suggests that most of their on
| road testing is done in the US. Michelin is a French company and
| there are lots of good European card companies. Does anyone know
| why they wouldn't do their testing in Europe?
| karambahh wrote:
| 16 years ago, I was an intern at the European HQ of a Japanese
| tyre brand.
|
| We received and chain forwarded a "leaked" video of Michelin
| testing a similar design.
|
| We ICT folks thought we were doomed as it seemed miles ahead of
| our own R&D.
|
| 16 years later and we are yet to see these tyres on the streets.
|
| This time, I'll believe it when I see it ;)
| jaclaz wrote:
| Previous related thread here (about one month ago):
|
| https://news.ycombinator.com/item?id=28537549
| ableal wrote:
| Thanks. Second comment:
|
| """
|
| I am an engineer working in the tire industry (throwaway is
| needed here). The Michelin "Tweel" IP was actually acquired
| when Michelin bought BF Goodrich 31 years ago. Goodrich
| developed the concept as a replacement for compact spare tires,
| doing the initial R&D in the 1980s. Every 3--5 years Michelin
| has a press release like this, and the technology is always 3--
| 5 years away from release. Currently the US DOT and it's
| equivalents abroad are still in the rulemaking phase regarding
| airfree technologies, so there's that, too.
|
| """
| mcguire wrote:
| Which brings up the one ideal use for these that hasn't been
| mentioned: spare tires, if you can make them narrower with
| the same load capacity.
| whatever1 wrote:
| Weren't we trying to reduce plastic waste? This seems to need
| multiple times the amount of rubber that a normal tire needs. And
| for what? To prevent a fixable puncture that may or may not
| happen in a lifespan of a tire?
| y04nn wrote:
| My reaction too. I would say the number of scraped tires due to
| wear far exceed those scrapped due to puncture. Also it looks
| like this airless tire contains much more rubber, that would
| increase the tire weight and would impact the fuel consumption.
| The final weight of rubber scrapped may also increase compared
| to conventional tiers. Airless tires have been discussed for
| many years, this is only marketing and brand PR.
| jedberg wrote:
| Have you ever been driving when a tire blew out at high speed?
| It's extremely dangerous not only for the driver but all the
| nearby cars.
|
| This is a tradeoff between environmental concerns and safety,
| as are most safety features on a car. We could make a car that
| gets insanely good milage and has little raw material, but it
| would be terribly unsafe.
| throwaway0a5e wrote:
| > Have you ever been driving when a tire blew out at high
| speed? It's extremely dangerous not only for the driver but
| all the nearby cars.
|
| Have you? Your characterization of the experience makes me
| think you have not.
|
| I have had two rear and one front blowout. Blowouts are just
| flat tires that have a loud intro before the typical "driving
| on flat tire" music. None of them were any more eventful than
| a normal flat tire. I'd take a blowout (or normal flat tire)
| over tread separation any day.
|
| The internet highly highly highly highly highly overrates the
| danger, likely because blowouts are so rare these days and
| unfamiliarity tends to result in fear which compounds the
| Internet's tendency to reward certain commenting patterns.
| Other than the noise potentially causing a driver to
| incorrectly make massive control inputs (which would be
| equally hazardous to do after suffering a normal flat) there
| is no more hazard from a blowout than from a normal flat. And
| I say this as someone who drives old junk with fat sidewalls.
| On something with small modern sidewalls all the danger is
| less still.
|
| Frankly, the one time I had a valve stem leak that caused a
| slow flat was much more unnerving as I initially wasn't sure
| if I was feeling things or if the vehicle was pulling to that
| side.
| jedberg wrote:
| I have. Front tire blew out, caused the car to swerve
| uncontrollably to the right. Luckily no one was there an I
| knew not to slam on the brakes but to downshift instead.
|
| But yes, in many cases it just drags the car. None the
| less, it can cause huge issues.
| whatever1 wrote:
| You are not talking about a puncture. You are talking about a
| catastrophic collapse of the tire from an impact (damn
| potholes) that has happened to me.
|
| I don't see how these tires are immune to catastrophic
| failure that typically can take with it the rim and the
| suspension.
| jedberg wrote:
| Punctures can cause those catastrophic failures, especially
| when they hit the edge near the sidewall.
| chinathrow wrote:
| Do tire manufacturers really have the desire to develop tires
| with less tear?
| ptsneves wrote:
| Yes if they can charge a premium, and keep product loyalty.
| Given they are targeting fleet reliability and up-time i can
| see it happening.
| dazc wrote:
| These tyres are also going to wear out just as much, or maybe
| faster, than standard tyres.
| [deleted]
| modeless wrote:
| I am skeptical that these will be better for the environment.
| Maybe there will be fewer tires discarded due to flats, but the
| tires will weigh more. That's more material discarded per tire
| and more energy to drive them around.
| AStrangeMorrow wrote:
| Maybe I am wrong, but I think I've red somewhere that these are
| made to be re-threaded. Meaning when the outer layer get
| damaged with use, instead of changing the whole tire, just the
| outer part can be replaced. Not too sure how that works though.
| If that is the case, it should help reduce the amount of waste
| by a lot. Plus even if these new tires are heavier, I doubt
| they are 10 times heavier either. I'd be surprised if the added
| weight to the car will increase the energy consumption in a
| very noticeable way.
| andylynch wrote:
| They call it 'recharging' on this page. They even propose
| converting between summer/winter by reprinting the tread.
| modeless wrote:
| Pneumatic tires can also be retreaded. But we generally
| don't do it for passenger cars. I'm not sure of the reasons
| why so I can't say whether these tires address any of them.
| I'd want to see some explanation before I believe it.
| Chris2048 wrote:
| Surely the ability to recycle/repurpose an old tyre matters
| more than the flats, so I'm not sure how this helps.
|
| Also, I see the biggest concern as degradation of tyres
| contributing to rubber-dust pollution: "according to the UK
| government, and they are the second largest source of
| microplastic pollutant in oceans after single-use plastic"
|
| Seems like it would be better to find an eco-friendly
| alternative to tyre rubber instead. If this design allows that
| (e.g. by allowing tyre materials that aren't as stretchy as an
| inflatable would need to be) I'm all for it, but that's a more
| complicated definition of "good for environment", dependant on
| _other_ tech being developed.
| ytechie wrote:
| Wouldn't these be great for trailers? Trailer blowouts are
| common, and often unnoticed, or can heavily damage the trailer. I
| have no interest in these on a car, but for a trailer, sign me
| up!
| throwaway0a5e wrote:
| I think they'd be better for trailers than cars because all the
| tradeoffs people are complaining about (small increase in
| rolling resistance, NVH, inability to air up for increased load
| or down for comfort) are far lesser in a trailer application.
| Combine that with all the trailer tires that go bad from long
| term exposure to the elements before they get worn out and it
| seems like an obvious application.
|
| But..... one of the most important aspects about trailer tires
| is cost and these may not quite be there yet. Michilin and
| other tire manufacturers don't really compete much in that
| space and leave it for the low end import brands to fight over.
|
| Rental trailers and towed equipment (like towed light plants
| and air compressors) seems like the only obvious niche where
| both the cost and downsides are justifiable.
| karmicthreat wrote:
| I will believe it once I see them drive the same tires on West
| Michigan roads for 29k miles during the spring. We've had
| highways just disintegrate during the thaw here.
| sgarrity wrote:
| I have airless tires in the same bucket as flying-cars and video-
| phones (things that sort of exist, but are always just around the
| corner from being widely adopted).
|
| (I realize that video-phones are kind of widely adopted now via
| Zoom/Facetime/etc. - I'm thinking more of the vision from the 90s
| of a telephone with a screen in your kitchen)
| zaptrem wrote:
| Those are also widely available now (ie Facebook Portal +
| similar), but nobody needs them. My grandparents had a similar
| model which they used until a few years ago.
| uwagar wrote:
| the michelin man is so full of air though
| taoufix wrote:
| I'm a bit confused. Are they going to leave the sides open like
| that? What if a pebble gets stuck in there?
| bkanber wrote:
| Former automotive engineer chiming in. "Tweels" have been around
| a long time, but have always failed in terms of "NVH" (noise,
| vibration, harshness). Michelin is claiming that this generation
| of tweels are appropriate for passenger cars, which means that
| they _think_ they 've solved the NVH problem.
|
| They seem to be marketing these alongside EVs, I wonder if
| they're only really intended for lighter, compact-style cars.
| (Edit: I'm talking about EVs like the BMW i3, which _are_ on
| average about 1000 lbs lighter than the cars most Americans
| drive, ie, the CUV /SUV form factor.)
| rolleiflex wrote:
| Do you think something like this would be made available for
| motorcycle tires? Motorcycles are significantly more vulnerable
| to tire-caused crashes because a motorcycle whose one tire
| violently decompresses on a highway or autobahn is very likely
| to have a crash since it can no longer balance, while a car
| that loses a tire still has 3 other tires and will still have
| plenty of traction and balance left to pull over. Something
| like this that makes violent decompression impossible would be
| a fairly big improvement to motorcycle safety.
| 8ytecoder wrote:
| Don't get me wrong - I'd expect Michelin to have done some
| testing to see NVH is within tolerance levels right?
|
| Airless is really close to working for bikes. If I were
| commuting on a bike now I'd be comfortable going for it. The
| downsides - painfully hard installation, uphill resistance,
| ...etc. - will be worth it.
| bkanber wrote:
| Bridgestone said bike tweels were close 4 years ago, and then
| again 2 years ago... I won't hold my breath! :)
| lost-found wrote:
| Michelin is by far the market leader in tires, especially
| compared to Bridgestone.
| 8ytecoder wrote:
| Tannus is the leader right now. I have tried it and I'm
| fairly comfortable. Again, the number of flats you get in
| some of the cities in the Bay Area is insane. That makes it
| worth it.
| LargoLasskhyfv wrote:
| Really? There are small cans of spray which you can have
| easily with you. Got a flat? Look where, pull it out. Spray
| the foam in. Turn the wheel for a minute, look for overseen
| leaks, maybe, and pull stuff out of them. Turn wheel a few
| more times. Pump. Or use car-adapter for pump at gas station.
| Those stuff costs between 2 and 4EUR for a can of sprayfoam,
| and maybe 50ct for a small adapter(sugar cube like, but
| cylindrical). Given the stuff Schwalbe and Continental are
| offering for normal bicycles, I don't get all the rage.
| Because a flat fixed like described above lasts about half a
| year, then the profile is too slick, and I change tire and
| tube.
|
| Works for me. Feels comfortable and fast. Is economic.
|
| YMMV.
| djrogers wrote:
| The last flat I had involved a 3" split in the tube - ain't
| no slime/foam/spray can that's gonna fix that.
| bserge wrote:
| I just used aramid fiber lining on the inside of my Vee
| Rubber tires (best stuff, fuck Conti and Schwalbe), haven't
| had a flat _yet_. Better than "puncture proof" shit from
| Conti.
|
| But it's probably just a matter of time before an
| exotically shaped piece of glass gets through :D
| 8ytecoder wrote:
| You make it sound simple. It's not when I'm commuting. Even
| to use the sprayfoam sealers - I need to first identify the
| puncture and that's not always obvious. I've usually just
| changed the entire tube.
| LargoLasskhyfv wrote:
| It's my experience. In case of unidentified punctures the
| foam leaks out (of them), and then you can remove the
| splinter, or whatever by hand, maybe with a paper tissue,
| or tweezers from your swiss officers knife, some
| multitool. Dunno. I don't have that many flats. About 5
| or 6 since 2005? Each one maybe a 10 to 15 minute break.
|
| edit: Thinking about it, one could even omit the spray
| can because in cities there's almost always a gas station
| near, which is stocking that stuff. So only the small
| adapter would be necessary, if your valves aren't like
| the ones for cars anyways. I didn't do that so far
| because I'm often bicycling out of the city, instead of
| into it.
| bkanber wrote:
| I also want to add, since this is more of a deep auto-
| industry thing, that NVH testing is _almost_ like
| longitudinal health studies. NVH engineers actually have
| charts of which specific frequencies _our internal organs
| resonate at_. For a layperson it 's easy to imagine that NVH
| testing is just a matter of setting up a dB meter and some
| accelerometers to make sure things aren't bouncing around too
| much, but it's actually much more nuanced than that, and the
| engineers have to consider the long-term effects of driving
| in the vehicle.
|
| One easy way to picture this is: recall your last long road
| trip, or airplane flight, anything more than 3 hours or so.
| You get _so tired_ after those, especially considering that
| you 've only just sat still for a few hours. But in actuality
| your body is making hundreds of tiny corrections to posture
| each minute, in response to the vibrations of the vehicle,
| and that literally exhausts your muscles and nervous system.
| Now imagine that you make that car "5% more harsh" and redo
| the road trip; you will feel the _compound_ effects of that
| additional harshness. Auto manufacturers take NVH _very
| seriously_ , because it turns out to be a pretty big deal.
|
| My point is that even if NVH comes back OK in the lab, they
| still will need a good deal of real world data with test
| subjects representative of the 'average driver' before they
| can make a determination.
|
| Edit to add: I know of at least one case where the entire
| drivetrain of a vehicle was redesigned due to NVH.
| chris_st wrote:
| A friend recommended I wear earplugs on plane flights, for
| a similar reason. He said that the constant noise stresses
| our bodies/minds, and lowering it makes the time more
| pleasant. It may entirely be placebo effect, but I find it
| very helpful.
| YossarianFrPrez wrote:
| This was very cool to read; thanks for such an informative
| comment.
|
| I imagine this will sound naive, but I wonder why this sort
| of vibration can't be addressed with shock absorbers in the
| seats?
| bkanber wrote:
| > I wonder why this sort of vibration can't be addressed
| with shock absorbers in the seats?
|
| Not at all naive, because it _is_ addressed with shock
| absorbers in the seats; that is one of the very many
| tools NVH engineers use. :) But they 're not 'shock
| absorbers' in the way you're thinking; the actual foams
| used in the car seats are specifically designed and
| selected to dampen certain frequencies. But, kind of like
| a speaker or headphones or even ear plugs, the dampening
| happens over a spectrum, and in general our organs
| resonate at lower frequencies, which are harder for
| foamlike materials to dampen.
|
| NVH engineers view the entire road-vehicle-driver system
| as a huge, complex, spring-mass-damper system, and do a
| whole ton of partial differential equations to solve for
| the outputs.
|
| Edit to add: so why not use traditional 'shock
| absorbers', the spring-damper kind that you're used to
| seeing? For passenger vehicles the answer is weight and
| complexity. But many trucks and tractors and so on do in
| fact have these.
| YossarianFrPrez wrote:
| Fascinating, thanks for the response.
| throwaway0a5e wrote:
| And this stuff is exactly why it's a million times less
| fatiguing to drive a vehicle from 2020 over one from 1990,
| even if you control for almost every other variable by
| picking one that has changed minimally (i.e. a few panel
| vans and many medium duty trucks)
| Pxtl wrote:
| EVs don't have space to store a donut so an airless system that
| can't deflate would be useful.
| djrogers wrote:
| That's malarkey. EVs have more than enough space for a donut.
| If manufacturers choose to not ship one, that's because they
| can same $$ and weight by not doing so - it's not due to
| space.
| Pxtl wrote:
| I drive a compact PHEV and there is literally no place to
| even put a spare, but that may be more because it's a PHEV
| and so it has to make room for both batteries _and_ engine.
| I know most compact EVs don 't come with spares and many
| don't even have a well to store one in.
| ddlsmurf wrote:
| Complete layman here, every 6 months or so for the past decade
| I see an article claiming someone got air-less tires working.
| What are the chances this would be it ?
| arghwhat wrote:
| A lot of heavy equipment drives around with water-filled
| tires, so it's already there. Definitely not what you meant
| though.
| xxpor wrote:
| Hmm, why water filled? I can't think of any advantages, but
| can think of downsides such as a massive increase in
| unsprung weight.
| kazinator wrote:
| A disadvantage is that only the rubber absorbs impacts,
| since the fluid is incompressible for all intents and
| purposes.
| cat199 wrote:
| ... but for 'intensive purposes' on the other hand the
| story is less clear
| robocat wrote:
| The tyre is only partially filled (for example 40%) with
| water - so the tyre is not "incompressible". https://sale
| smanual.deere.com/sales/salesmanual/en_NA/tracto...
| kazinator wrote:
| I see. Furthermore, there is an admonishment:
|
| _IMPORTANT: Never fill any tire to more than 90% full.
| More solution could damage tire._
| throwaway0a5e wrote:
| Ballast for increased traction and tipping capacity with
| the positive side effect of lower COG.
| xxpor wrote:
| Ah! That's a good idea.
| fergbrain wrote:
| Sounds like it's used as ballast:
| https://tractoraddict.com/tractor-tires-filled-with-
| water/
| erik_landerholm wrote:
| https://tractoraddict.com/tractor-tires-filled-with-
| water/
|
| Beet juice is interesting! lol
| throwaway0a5e wrote:
| Beet juice is soooooooo much better for the environment
| than the salts it is replacing. Unfortunately it is
| slightly more expensive so we get to continue poisoning
| our waterways with salts.
| LeifCarrotson wrote:
| It's a lot better than the calcium chloride that they
| used to use, when a telehandler blew out a tire and
| drained hundreds of pounds of saltwater into my parents'
| lawn a few years ago it did a lot of damage.
| jet_32951 wrote:
| The only springs on most tractors - ancient or modern -
| are between the seat and the frame to which it is
| affixed. IOW the vast majority of the tractor's total
| weight is unsprung.
| dboreham wrote:
| Nothing is sprung on a wheel loader or a scaper.
| dboreham wrote:
| Sometimes foam is used rather than water.
| bluGill wrote:
| The only time they move fast enough to worry about
| unspung weight is when they are on a trailer.
|
| That isn't strictly true, but in general such equipment
| spends most of it time moving very slowly it it moves at
| all. Transports speeds do become a problem, but that is
| only done for a short time (or you have it on a trailer
| so you can go faster) so nobody worries about the issue.
| handrous wrote:
| Water's basically incompressible, if some Michael
| Crichton book I read like 25 years ago is to be believed.
|
| My guess would be one or more of: the above; greater heat
| capacity; or, something to do with surface area vs.
| volume meaning that at a large enough size water in a
| tire is far lower-pressure and easier to contain than air
| at a high enough pressure to keep it inflated, and/or,
| relatedly, something to do with heat dissipation from
| compressing gasses being really hard to deal with once
| you hit a certain surface-to-volume ratio.
|
| [EDIT] LOL, guess all these were wrong and it's just for
| the extra weight.
| 1-more wrote:
| The book was Sphere. It rocked. I too remember this fact
| just from that.
| beauzero wrote:
| Its easier to let the water out of a tractor tire than to
| take a 500lb wheel plate off...when changing a tire.
|
| ...added weight is for better traction. Almost all 2WD
| tractors will have their back tires filled with a
| water/radiator fluid mixture (ice doesn't work well if
| you want to keep the tire on the rim).
| legulere wrote:
| Also trains drive around with solid metal tires.
| throwaway0a5e wrote:
| Trains have the benefit of exceptionally smooth "roads"
| bkanber wrote:
| At some point they will be viable... whether _this_ is that
| point or not is yet to be seen.
| OnlineGladiator wrote:
| > At some point they will be viable
|
| Why do you assume this?
| bkanber wrote:
| Because this is primarily a materials science problem,
| and we are still novices at materials science.
| rightbyte wrote:
| There does not have to exist a solid material with the
| properties of a gas.
| bkanber wrote:
| What? I don't understand what you mean by that.
| rightbyte wrote:
| As he said, more or less. Sorry for being cryptic.
|
| "There's no reason to assume this is a solvable problem"
| OnlineGladiator wrote:
| There's no reason to assume this is a solvable problem,
| just because it's a new field. I remember when cold
| fusion was considered inevitable.
|
| You don't actually have any reason to assume it will
| happen other than blind optimism.
| bkanber wrote:
| ... you don't actually have any reason to assume it won't
| happen other than blind pessimism. So let's just agree to
| disagree.
| OnlineGladiator wrote:
| I love to disagree because I'm a betting man. Want to
| wager some money on a bet? Pick a timeline (5 years, 10
| years, 20 years, 50 years) and maybe we can make this
| fun!
| gregoriol wrote:
| Because at some point we used wood for wheels?
| _jal wrote:
| You can still use wood if you want.
|
| Many of the reasons you don't are the same reasons
| airless tires have not escaped niches.
| bserge wrote:
| Hmm, not the worst idea. But who makes wood tires for
| bikes nowadays? And oh God, the splinters :D
| dahfizz wrote:
| How does wood --> inflated rubber imply inflated
| rubber--> airless rubber? I don't see any logic in that.
| hollander wrote:
| I use nitro oxygen in my tyres. Pressure problems are gone.
| dsr_ wrote:
| The Earth's atmosphere is about 80% nitrogen and a little
| less than 20% oxygen, with some carbon dioxide, argon,
| variable amounts of water vapor, and some pollution.
|
| What's "nitro oxygen", then?
| marcosdumay wrote:
| I imagine it's a joke on people that use nitrogen.
| dylan604 wrote:
| https://www.tireamerica.com/resource/nitrogen-vs-oxygen-
| for-...
|
| That at least helps with some of the logic. However,
| doesn't directly answer what "nitro oxygen" is. Guessing
| some sort of slang. It's definitely not a scientific
| phrase. Nitrogen oxide or something maybe too much for
| grease monkies so they call it nitro oxygen??? just
| guessing.
| bkanber wrote:
| My guess is parent comment misspoke and meant pure
| nitrogen -- which does indeed help with tire pressure.
| The ideal gas law still applies, so there will be
| seasonal changes in pressure, but there will be much less
| exfiltration (via 'permeation', specifically) of gas
| through the material (N2 has a larger 'kinetic diameter'
| than O2; O2 will permeate 3-4x faster through rubber than
| N2).
| checker wrote:
| So if regular air is 80% nitrogen already, won't the
| tires move towards 100% nitrogen with each top off since
| the tires will be retaining the nitrogen more than the
| oxygen? Sounds like a marketing trick unless they're
| filling newly mounted tires with 100% nitrogen.
| bkanber wrote:
| That's a pretty clever thought in general, but yours is
| only a first approximation.
|
| First, permeation decreases with pressure, at different
| rates for the two gases. If you consider _only_ this fact
| you will find that the partial pressures of O2 and N2
| asymptotically approach homeostasis, rather than simply
| all the O2 leaving and all the N2 remaining.
|
| Second, permeability changes with temperature, so the
| ratio of O2 and N2 exfiltration rate changes seasonally,
| as each gas has a different permeability-vs-temperature
| curve. Third, the ideal gas law causes pressure changes
| seasonally which will also decrease exfiltration in
| winter, and once again, each gas will have its own
| permeability-vs-pressure curve, so these become very
| confounding factors.
|
| All in all, the reality of the situation is that filling
| up your tires with atmospheric air will probably settle
| on partial pressure ratios of, say, 85/15 rather than
| 100/0. The deflation that you get comes from only about
| 5% of the O2 leaving the tire; and of course you get
| another big deflation when the weather first turns cold.
|
| I don't know the exact numbers because I've frankly never
| thought to look into this before. So like I said, it was
| a clever thought! But it needed to be taken a few steps
| further.
| checker wrote:
| Thanks! I love getting answers like this from the
| community.
| bananapear wrote:
| Maybe just nitrogen? Costco inflates tyres with nitrogen.
| The pair of tyres on my vehicle inflated with nitrogen
| don't seem to lose pressure, the other two need topping
| up occasionally.
| throwaway0a5e wrote:
| That's the point. He's being sarcastic and calling
| "atmospheric air" "nitro oxygen"
| kllrnohj wrote:
| Air-less tires have been working fine for decades:
| https://www.nasa.gov/specials/wheels/
|
| You'll also find industrial equipment examples like
| https://www.sourceproequipment.com.au/crocodile-skid-
| steer-b...
|
| As the person you're replying to said, though, the problem
| for passenger cars is NVH. They aren't quiet.
|
| Even with that downside, though, they are still used in
| consumer-facing applications like some bike sharing programs:
| https://medium.com/@fredchang/by-now-youve-probably-heard-
| of...
|
| Where a smoother ride is less significant than unlocking a
| bike & finding a flat tire.
| bserge wrote:
| What the hell, I've been looking for something like this
| for the past few months. Only ones I could find were Tannus
| (too soft) and Schwalbe (garbage).
|
| Don't care about weight, noise, ride quality, just need
| unbreakable tires because riding through neighborhoods
| where people break glass bottles on the bike paths will
| make me smash someone's head with one someday.
| ctime wrote:
| Continental Gatorskin brand tires have worked really well
| in my experience, easily many thousands of miles. They
| usually age out (2 years or so) before I've had any flat.
| I have had snakebite flats though which is usually just
| due to low air pressure or bad tubes. Tubes can just
| suck. I've combined them with puncture resistant tubes
| (thicker tubes) and never had a flat, using 700x25 or
| 700x28 versions.
|
| https://www.continental-tires.com/bicycle/tires/race-
| tires/g...
| gambiting wrote:
| How about just regular Schwalbe Marathons Plus? In my
| experience those tyres are literally unpuncturable(at the
| cost of a huge weight penalty).
| ch33zer wrote:
| I rode across the country on a pair (two pairs actually,
| first set wore out) of marathon pluses. I got 1 flat from
| a metal staple, which is pretty good for 4200 miles :D
| noobermin wrote:
| Sorry for the conversation pivot, but this attitude sucks and
| is terrible for climate change and was decided wholesale by
| suppliers. While SUVs are leading sales in the US, it was the
| decision by car manufacturers to discontinue sales of anything
| other than SUVs in the US. That you say, "well these wheels
| which would reduce waste aren't useful for Americans," they are
| partly not useful because the car industry here pushed through
| advertising pressure (and yes, due to demand in part) for that
| outcome, it's a coupled two way street. So, that same industry
| bears some of the blame.
| WillPostForFood wrote:
| _While SUVs are leading sales in the US, it was the decision
| by car manufacturers to discontinue sales of anything other
| than SUVs in the US_
|
| ?? Cars are available for sale in the US.
|
| https://www.statista.com/statistics/199981/us-car-and-
| truck-...
| thefounder wrote:
| Nah...americans like big cars and manufacturers followed the
| sales! Even worse, europeans started to like big cars too...I
| just don't get why people like to drive big SUVs in the city.
| WorldMaker wrote:
| "Like" is a strong word.
|
| On the one side you've got the tragedy of the commons that
| is big vehicles are less safe for other people to be around
| unless they two are in a big vehicle.
|
| On the other side, Tesla, Toyota, Honda, and Nissan still
| all have relatively strong sales of sedans in the US. The
| US market decided that sedans were best from "imports"
| decades ago and GM/Ford just gave up trying to compete.
| Then there's of course Tesla telling GM/Ford exactly where
| the hockey puck was going if they wanted to compete with
| "imports".
| fischert wrote:
| This is why regulation is needed. States do not allow any
| kind of car on the streets. But often car manufacturers say
| it will threaten economy and labor.
| simonebrunozzi wrote:
| Nah. SUVs above a certain weight pay less taxes [0], that's
| why automakers aggressively marketed them for decades and
| finally managed to convince Americans that SUVs are cool.
|
| [0]: https://www.irs.gov/publications/p946
| djrogers wrote:
| The vast majority of people don't commercially depreciate
| their vehicles, so while this does apply to some, it's a
| relatively small group.
|
| In my huge group of friends, I know one person who does
| this with his truck, and he readily admits that it
| involves lying to the IRS and it fraud. Everyone else
| with a big SUV just prefers them to minivans.
| WillPostForFood wrote:
| There is also a gas guzzler tax that only applies to
| cars. If it was applied evenly, most trucks and SUVs
| would be paying a tax penalty for poor mileage. So there
| is a kind of indirect government subsidy to bigger
| vehicles. It is a dumb policy, but it's not why people
| like SUVs.
| acdha wrote:
| There's some truth to that - remember the surveys where
| parents said that they could imagine driving an SUV but not
| a minivan if they divorced & were dating again? - but they
| were also subsidized. If the price of gas wasn't
| artificially low, or they had to meet the same safety and
| pollution standards as everything else, they'd be less
| popular. We did at least close the Hummer tax write-off,
| but we should be doing more on the safety front since SUV
| drivers reversed a decades-long run of fatality reductions.
| BoorishBears wrote:
| It doesn't work like that anymore.
|
| 99% of the "SUVs" you see today are CUVs, which in turn
| are barely more than a lifted sedan.
|
| So the difference is gas milage is miniscule, to the
| point gas prices will no longer affect the sales of the
| most successful SUVs
| nonameiguess wrote:
| I'm not trying to defend myself or anything since I don't
| even have a car, but when I did, it was always an SUV. It
| wasn't so much a matter of preference as necessity. I'm not
| exactly huge, only 6'2", but if I try to drive my wife's
| GTI, I'm hunched over and hitting my head on the ceiling.
| Only way to do it is leaning severely back with the seat
| reclined. Trying to be a backseat passenger in an average
| sedan is completely impossible. Even though it's at least
| possible to drive a car like that, if not comfortably, it
| definitely isn't safe, since visibility is shot to shit
| with the tiny mirrors and your head and elbows running into
| something every time you try to turn to cover your blind
| spots.
|
| Contrast that with an SUV. No need to lean or hunch. You
| can see everything without trouble. You can move without
| trouble. It's actually possible to use the backseat.
| phinnaeus wrote:
| I'm an inch or so taller than you and have driven a GTI,
| along with other small cars, very comfortably for more
| than 10 years.
|
| Clearly this is a situation where, quite literally, YMMV.
| DoingIsLearning wrote:
| The interior space of an MPV is typically bigger than an
| SUV.
|
| Considering the sales numbers of MPVs, it would seem that
| the argument you make is not what is pushing the
| disproportionate commercial success of SUVs.
| laurent123456 wrote:
| What? I'm about the same height and drive a sedan just
| fine, and it's comfortable and safe. I don't know how
| small your wife's car is, but I've never been in one so
| small that I'm bumping my head in the ceiling, that would
| be weird.
| mauvehaus wrote:
| GP is probably proportioned like Michael Phelps: short
| legs, long torso.
|
| I'm of a similar height, but oppositely proportioned, and
| the driver's seat in most cars doesn't go back far enough
| that my lower thighs rest on the seat, which makes for a
| lot of butt discomfort on long trips.
|
| If the seat does go back far enough for my legs to be
| comfortable, it's almost unavoidable that the steering
| wheel is uncomfortably far away, and I put the seat
| pretty close to bolt upright to put my shoulders closer
| and reduce the impression that I'm hanging on to the
| wheel for dear life as it's trying to pull away from me.
|
| Bicycles are similarly problematic: I want a shorter top
| tube than is common for my nominal frame size, so I ride
| a 59cm road bike frame with a short stem and a lot of
| seatpost showing. You'd be more likely to find somebody
| with my inseam (34" [0]) on a 61cm or 63cm frame.
|
| [0] Sorry for the mixed units. I'm giving them in the
| trade sizes. Road bikes are sized in metric, and pants
| are sized in inches, at least in the US.
| discreteevent wrote:
| > europeans started to like big cars too
|
| I saw a documentary on this once where they interviewed
| some psych guy who was advising the car industry. He said
| that it took him some time to convince them to make
| everything ridiculously big. Not just the car, but the
| lights etc. It was based on his theory that when we first
| see something we evaluate it using the bit of our brain
| that has been there since we were lizards. And that bit is
| impressed by size. His theory was that it overrides
| everything. Most people will pick the bigger thing. He was
| right.
| TaylorAlexander wrote:
| Yeah the role of marketing in influencing public opinion
| should not be discounted.
| kbelder wrote:
| That was public opinion influencing marketing.
| [deleted]
| brightball wrote:
| I remember Michelin talking about these before but seem to
| recall that the biggest impediment was cannibalization concerns
| from existing departments.
| andrewblossom wrote:
| Compact EVs aren't "lighter" though, are they? I wonder if it
| is the inverse of that - heavier compact-style cars with
| relatively large amounts of sprung weight.
| bkanber wrote:
| The issue with tweels is generally the unsprung mass, not the
| sprung mass. In general they will want to install tweels on
| vehicles with lower unsprung mass, which means smaller form
| factor (again, in general).
|
| And I should have been a little clearer in my parent post:
| I'm mentally comparing something like the BMW i3 to something
| like the BMW X3; the i3 is about 1000 pounds lighter.
| 725686 wrote:
| Maybe the noise they generate is good for EVs which are
| dangerously quiet for pedestrians?
| smilekzs wrote:
| Valid point, although pedestrian safety is mostly discussed
| in the low-to-mid-speed regime (<= 45 MPH), while tire noise
| (at least according to my own observation) dominates in the
| high speed regime (>= 65 MPH). There might be some overlap
| though.
|
| Also worth pointing out: NVH is not just Noise --- it
| includes Vibration and Harshness that are only felt by the
| people inside the vehicle.
| Scoundreller wrote:
| And effective at rattling off any untorqued/loose
| nuts/bolts.
| agumonkey wrote:
| Some EVs have mandatory sound emitters to not be fully silent
| (and thus dangerous). I thought it was weird harmonics from
| the synRM engine but it's synthetic and enforced by
| regulations.
| throwaway0a5e wrote:
| I thought it was a plastic valence rubbing on something.
| agumonkey wrote:
| nah it's on purpose
| https://www.youtube.com/watch?v=mNkGD_Sryxg
| arecurrence wrote:
| Hybrids as well. The Toyota Prius has had this at low
| velocities since before EV cars were mass produced (I
| believe Toyota uses a speaker that makes a sort of sci fi
| sound). It is a legal requirement to generate a minimum
| amount of noise to sell a car in some countries.
| ggreer wrote:
| Every EV sold today must make noise at low speeds.[1]
|
| 1. https://en.wikipedia.org/wiki/Electric_vehicle_warning_sou
| nd...
| dharmab wrote:
| Ironically NVH is even more important in EVs since the engine
| noise no longer drowns out unpleasant sounds like fan motors,
| hums, squeaks/rattles
| speedgoose wrote:
| You can ear an EV very well, the rolling noise and the wind
| noise is difficult to miss. Of course if the EV is driven
| very slowly it's not noisy unless it has a fake sound like
| many does, but it's not very dangerous either.
| KptMarchewa wrote:
| EVs are usually much heavier than gas cars.
| bkanber wrote:
| For the same form factor, yes that's true.
| ggreer wrote:
| I don't think that's true anymore. For example, the Tesla
| Model 3 weighs anywhere from 3,552-4,072lbs depending on the
| trim level.[1] (The heaviest is the Model 3 Performance which
| has the biggest battery, motors, and wheels.) The BMW 3
| series is 3,582-4,138lbs depending on the exact model and
| trim.[2]
|
| Gas cars don't have big heavy batteries but they do have big
| heavy engine blocks and more complicated (heavier)
| drivetrains.
|
| 1. https://en.wikipedia.org/wiki/Tesla_Model_3
|
| 2. https://www.caranddriver.com/bmw/3-series/specs
| mitigating wrote:
| BMW is a particularly heavy sedan. The Honda Civic is 2877
| to 3126. Even the Golf R which has a rear diff, DCT, and a
| 2.0 turbo is only 3100 pounds.
| ggreer wrote:
| I picked a gas car of comparable size. The Civic and Golf
| are much smaller than the Model 3.
| kube-system wrote:
| The Civic is 2 inches shorter and 2 inches narrower than
| the Model 3, but it actually has a larger interior volume
| by one cubic foot.
|
| Size up to the Accord which is 8 inches longer and a half
| inch wider than a Model 3 (and 9ft^3 more interior
| space), and it still only weighs 3131-3362 lbs.
| ggreer wrote:
| Where are you getting those figures? When I look up the
| stats for the 2021 Accord I see weights ranging from
| 3,150-3,446lbs.[1]
|
| Really though, the Civic and Accord aren't competing with
| the Model 3. They're front wheel drive. They have less
| power and torque. They use struts for the front
| suspension. All of these measures save significant weight
| (and cost). That's why I picked the BMW 3 series. It's
| similar size, performance, and cost. If we look at other
| competitors to the Model 3 we get similar weights:
|
| - Volvo S60: 3,724-4,468lbs. (The low number is front
| wheel drive. The high number is a plug-in hybrid.)
|
| - Audi A4: 3,682-3,726lbs.
|
| - Mercedes C-Class: 3,472-3,605lbs.
|
| - Cadillac CT4: 3,422-3,616lbs.
|
| - Volkswagen Passat: 3,014-3,794lbs. (The lighter
| versions are front wheel drive only. The heavier versions
| are hybrids.)
|
| In general, fancier cars are heavier. Also safer cars
| tend to be heavier. Yes batteries are heavy, but so are
| engines, drivetrains, starter motors, turbochargers,
| exhaust systems, fuel tanks, and so on. Early electric
| cars were significantly heavier because they were based
| on combustion platforms. When EVs are designed from the
| ground up, the weight penalty is less than 10%. Vehicle
| models in the same market segment vary more than that,
| and some combustion vehicles are already heavier than
| their electric competitors. This will likely get better
| with time as battery technology improves.
|
| The statement "EVs are heavier" is approximately as true
| as "AWD vehicles are heavier". All else equal it's more
| likely than not, but the difference is rarely enough to
| matter for any practical purpose.
|
| 1. https://www.caranddriver.com/honda/accord/specs/2021/h
| onda_a...
| mcguire wrote:
| And the GMC Yukon is 5500-5800 lbs, which is what I
| expect the original comment to be making a comparison
| with.
| jsight wrote:
| The 3 has at least 5 cubic feet more in cargo space than
| the Civic. In practice there is a pretty big difference
| between those two cars.
| kube-system wrote:
| The Civic and 3 both have 15 ft^3 of cargo space
| according to the EPA.
|
| Regardless, the Accord dwarfs it and supports the above
| point that the Model 3 is a heavy car, and the BMW 3
| series is heavy because it was built to have a premium
| feel as a design priority, not because it is ICE.
| throwaway803453 wrote:
| Does the focus on NVH imply that the increase of rolling
| friction over time is negligible compared to the tread lifetime
| ? Or is that partly of the reason to target lighter vehicles.
|
| The above assumes the spokes(?) become stretched over time it
| would increase displacement of the center of rotation from the
| center of mass which if recall is what creates rolling
| friction.
| bkanber wrote:
| For two tires with equal interior volume, the rolling
| resistance of a tweel will be much much greater than the
| rolling resistance of a normal tire.
|
| That said, tweels are typically designed to be much thinner
| and have much less interior volume than air-filled, in order
| to close the gap in rolling resistance. So you'd really need
| to compare a specific model tire against another specific
| model tweel in tests to know. But my intuition tells me that
| the rolling resistance will still be worse almost no-matter-
| what with today's tech.
|
| So that's partly the reason they target lighter vehicles, and
| that's partly the reason they seem to be marketing around EVs
| specifically. That extra rolling resistance may be worth a
| few $s in gas each month vs only a few cents in electricity
| for the same driving conditions.
| KennyBlanken wrote:
| The marketing focuses heavily on reduction in disposed tires
| as the environmental benefit. If the tire were equal in terms
| of rolling resistance we'd see them at least mentioning it in
| the graphics.
| flurie wrote:
| EVs are quite heavy for their footprint due to the weight of
| the batteries.
| [deleted]
| tromp wrote:
| There are exceptions though like the upcoming Aptera which
| only weighs around 800 kg even with a large range.
| kube-system wrote:
| I'll believe it when it happens. Aptera has gone out of
| business more times than they have released a production
| car.
| stouset wrote:
| I remember being excited about the Aptera twelve years ago.
| I'll maybe get excited again once they actually start
| shipping a vehicle. They've already gone out of business
| once.
| jsight wrote:
| Unfortunately, they are also making a lot of claims that
| they haven't demonstrated in a working vehicle yet. Getting
| to production is going to be hard.
| gibolt wrote:
| This will change with improved batteries, charging
| infrastructure, and shrinking EV tech. By the time this could
| hit the market, hopefully the weight difference would be less
| stark.
| tibbydudeza wrote:
| Also don't you need to change the traditional car suspension
| system (McPherson struts, wishbones, shock absorbers etc ... )
| to even use these tyres ???.
| moneywoes wrote:
| Is there a reason this technology is not used on bikes which
| weigh a lot less?
| djrogers wrote:
| Because for a bike it's much simpler - make the tire solid,
| or a reasonably solid foam, and you're done.
|
| These have been available for years - look at Tannus for a
| good example.
| slownews45 wrote:
| This does still look to be a marketing excercise for now - I
| see no product availability to market in 6-12 months still.
| belter wrote:
| For utility vehicles on sale now, it seems:
|
| https://tweel.michelinman.com/michelin-tweel-family-of-
| produ...
| slownews45 wrote:
| That product has been out for 5+ years I think (at least).
| Plenty of airless in low speed / farm type applications.
|
| The real thing here would be high speed (65+) with good
| ride / noise.
|
| Maybe launch on local fleet delivery vehicles first (ie,
| neighborhood driving etc) if there were some lighter
| options there? Service pickup trucks (light?).
| rahimiali wrote:
| The page uses the phrase "revolutionary structure". It's a
| fascinating pun to make about a wheel. I wonder if it's
| intentional.
| themodelplumber wrote:
| Or it could just be both...a wheel with revolutionary
| structure, since wheels are nowadays so much more of an
| engineering project than a simple circle drawing in a book on
| theory...
| henry_bone wrote:
| I get that "no punctures means less waste", and "Every year, 20%*
| of tires are discarded as scrap due to flats and rapid pressure
| loss (12%) or irregular wear and tear caused by poor tire
| pressure (8%), i.e., the equivalent of 200 million tires, or 2
| million tonnes*. That's 200 times the weight of the Eiffel
| Tower."
|
| However, there is still the problem of getting rid of "a flexible
| load-bearing structure made from glass fiber reinforced plastic
| (GFRP)".
|
| I would hope there is a way to degrade, reclaim or reuse these
| materials.
| toomuchtodo wrote:
| Plasma gasification
| aezell wrote:
| I see a LOT of lawnmowers in my area with this kind of tire. It's
| especially prevalent on the larger, commercial mowers that
| landscape professionals use.
| rbanffy wrote:
| I wonder if the rubber structural spokes could be shaped to pull
| air from the underside of the vehicle (tire rotation would be
| slightly more complicated) to increase stability at higher
| speeds.
| pomian wrote:
| Or cooling. There also might not be expansion with increase
| temperature?
| rbanffy wrote:
| The wheels themselves could pull air through the brake disks,
| but their rotation and the shape of ventilated disks already
| help with that.
|
| I think I'll need to instrument my car. If something like
| this works, it'll seem from the inside the gets heavier the
| faster it goes in addition to what clever airfoils and
| aerodynamic design already does.
| JAlexoid wrote:
| They aren't airless, they just don't depend on compressed gas.
| moolcool wrote:
| Technically correct
| JAlexoid wrote:
| The best kind of correct
| danans wrote:
| By that definition, almost nothing but the vacuum of space is
| airless. Even a galvanized rubber hockey puck is going to have
| some amount of air in it.
|
| Airless in this case means that they don't use pressurized air
| for rigidity, and therefore they do not need to be engineered
| to maintain air pressure, thereby reducing material input, and
| removing a major failure mode.
|
| They are wheel-shaped springs.
| alecst wrote:
| What technology finally brought this idea to market? I'm
| impressed and happy that it exists, but it seems like this should
| have been around years ago.
| bkanber wrote:
| They were around years ago; Michelin's first tweel was
| developed in 2004.
| Yizahi wrote:
| I don't worry about punctures at all, despite living in a country
| with a shitty roads. What I worry about A LOT is a catastrophic
| collision of tire with a 90 degree sharp pothole edge, often made
| by roadworkers before doing point repair, which potentially can
| destroy tire irreparably. I wonder if these tires are better
| protected against such impacts, and just looking at them it seems
| they are - no side walls which are cut in a strong impact.
| Looking forward to more impact tests of these tires.
| InvaderFizz wrote:
| I'm in the same boat.
|
| I lose 1-2 tires per year due to sidewall damage from potholes.
| Lucky for me, the Discount Tire road hazard warranty covers
| that. Costs me $16/tire each time this happens.
|
| It's so bad that I had to replace the factory wheels with
| aftermarket ones that wouldn't get bent from the impact.
|
| Of course, I didn't consider changing the wheel size when I did
| that. I should have gone with 15" wheels and a higher ratio
| tire to get the same effective outside radius with more tire
| between the wheel and the road.
|
| Oh well, replacing this car soon anyways as now I am in need of
| ground clearance and AWD due to having moved to where roads do
| not always exist year round.
| drawkbox wrote:
| Additionally, tires filled with air can be dangerous over or
| under filling them.
|
| Filling tires at too high pressure can lead to blowouts.
|
| Filling tires under pressure leads to degraded performance
| handling issues potentially causing accidents in some cases.
|
| A more consistent normalized baseline performing tire, even if
| louder, would be welcome. This would end the seasonal low
| pressure tires in winter due to the cold and higher pressure
| during summer due to the heat.
|
| One time we got new tires and went on vacation and parked our
| car in an outside parking garage in a hot summer for a week, we
| came back and the side facing the sun the tires had exceeded
| PSI max and started to buckle. I am sure we have all seen those
| videos of people standing over tires and overfilling them
| leading to essentially a pressure bomb. Managing air pressure
| in tires can be problematic, airless tires are a welcome
| innovation.
| bkanber wrote:
| These tires do have sidewalls. The sidewalls are removed for
| marketing and demonstration purposes only.
| cjrp wrote:
| I guess the point is if they can be removed for
| demonstrations, then they're not critical to the structure.
| bkanber wrote:
| Sidewalls are critical for NVH at higher speeds, as well as
| fuel economy. But a demo of a tire on a car going 55 mph
| doesn't make sense, so they are able to remove the
| sidewalls for these stationary photoshoots and low speed
| rolling tests.
| sparrish wrote:
| I imagine they're critical for noise reduction.
| sfe22 wrote:
| They may be for real world usage, you dont want rocks or
| sticks getting inside
| cjrp wrote:
| Absolutely, my point was that if you can remove them for
| this sort of demo, then if they get damaged by a pothole
| then it's probably easy to replace them.
| kube-system wrote:
| The demo tires shown here don't have "removable"
| sidewalls. They were manufactured without them. The
| production tires will be one piece, like normal tires.
| marcellus23 wrote:
| I'm sure everyone in the tire industry (?) knows that, but it
| would be nice if Michelin had something to suggest that on
| their page.
| bkanber wrote:
| The only little clue is that one photo of the EV where the
| sidewalls are visible on the tires. You have to squint to
| see it :)
| marcellus23 wrote:
| good catch!
| jacquesm wrote:
| Totally missed that on first reading, thank you for
| pointing it out.
| kwhitefoot wrote:
| Same here. In over forty years of driving I have had only two
| tyres fail that I noticed while driving: one went flat over a
| period of a few seconds and the other was as you described, a
| pothole, I was only doing about 30 km per hour but the tyre was
| damaged beyond repair. In addition I've had a couple of slow
| leaks due to nails embedded in the tread but they were so slow
| that I didn't notice for days.
| intrasight wrote:
| Other comments here say that production tires will have
| sidewalls to protect the spokes and keep out rocks. If so, I'm
| a bit disappointed since I like the look of the spokes.
|
| Regarding catastrophic collision with sharp edge, I think these
| tires will be susceptible as well. If it's enough of a bump to
| "bottom out", it's going to dent the rim.
|
| Also, your comment about potholes reminded me of a time that I
| was driving with a friend and we hit a pothole and got a flat.
| My friend was driving and looked a the flat front tire and said
| "I'm glad I have a spare". I look at the flat back tire and
| said "Unless you have two, we're still going to need
| assistance."
| Steltek wrote:
| Are those spokes or springs? My mind had defaulted to
| "springs" given the zipzag shape and the typical function of
| a pneumatic tire. It didn't occur to me that they could
| function like spokes, where the vehicle hangs off the upper
| springs, until I read your comment. Why would the rim be so
| large and solid?
| intrasight wrote:
| > Why would the rim be so large and solid
|
| Not sure. Makes me think that it would be a good idea to
| make the inner rim diameter smaller, and have another layer
| of spokes/spings with a higher compression force.
| elif wrote:
| i'm pretty sure you'd have about a hundred whistles if you
| left the voids exposed at highway speed.
| _fat_santa wrote:
| > My friend was driving and looked a the flat front tire and
| said "I'm glad I have a spare". I look at the flat back tire
| and said "Unless you have two, we're still going to need
| assistance.
|
| I did this one time. Ran over a pothole and bottomed out. As
| I'm replacing my front tire I look to my rear tire and see
| that it's also flat. That wasn't even the cherry on top. At
| that point I had my front wheel off and tried putting on the
| spare anyways.
|
| I had a Kia Stinger GT and the GT version has Brembo brakes
| which have a much larger caliper than the regular version.
| Well QA at Kia never thought to check if their spare tire
| actually fits with the larger caliper. Spoiler alert: it
| doesn't.
| hammock wrote:
| How do you like the Stinger? I saw one of those the other
| day and did a double take on the Kia logo.
| zubiaur wrote:
| Been there, with a GM with a similar issue.
|
| The manual stated something about putting the spare on a
| rear, then, taking the good rear and putting it in the
| front.
|
| The rotors on the rear were smaller and could accommodate
| the spare. Obviously a moot point if one has two blown
| tires.
| mcguire wrote:
| If you can't fix the bug, document the work-around.
| cantsingh wrote:
| Same situation. I usually pride myself on having good
| situational awareness, but something about the shock of
| suddenly having a flat on a major highway took it out of
| me. I replaced my front right tire, pulled back into the
| slow lane, only to finally realize my back right tire had
| also been blown out. I called roadside assistance, left the
| car there, and Uber'd home.
|
| That was a rough day.
| rodgerd wrote:
| Punctures are much more of a problem for me - the roads are
| generally good, but tradies seem to love scattering nails,
| bolts, and other random bits of construction crap on the roads.
| tyingq wrote:
| Also handy for Michelin revenues that the wheel is integrated.
|
| Yes, I get that it might be hard for them to be separate.
| t3rabytes wrote:
| Michelin has been talking about these things for years and has
| yet to actually put them into production. All talk and no show.
| spcebar wrote:
| What does this mean for those 'severe tire damage' traffic
| control devices?
| dreamcompiler wrote:
| It means they probably won't work anymore. But they're mostly
| theater anyway; they are easily defeated.
| ur-whale wrote:
| Ride comfort on those?
| bkanber wrote:
| Ride comfort on tweels has historically been poor. But Michelin
| seems to be claiming they've solved that problem for this
| generation.
| syncsynchalt wrote:
| The same claim has been made yearly for the past century and
| a half.
|
| I don't think that any advancement in materials or mechanical
| science can create a solution that outperforms the advantages
| of a standard pneumatic tire.
| intrasight wrote:
| Good video I just found https://m.youtube.com/watch?v=Ql0Mkr3dwNU
| markild wrote:
| Interesting that they say nothing about consumption. I would
| expect them to be less fuel efficient, but having some number to
| go by would be nice.
| bkanber wrote:
| As a general rule, tweels are worse for fuel consumption --
| they are both heavier and have more rolling resistance. (Edit:
| weight automatically adds rolling resistance, but so does
| flexion, which tweels have more of. So tweels are a double-
| whammy for fuel economy.)
| kbenson wrote:
| I wonder how that breakdown works for under inflated and
| overinflated tires, and what percentage of the nations tires
| are in that state at any moment?
|
| For a consumer product like this I think it's probably more
| important to compare the common case than the optimal case,
| because I know my tires often aren't in an optimal state, and
| as much as we could save as a nation by making sure tires
| were inflated correctly, we just don't, and I don't expect
| that to change meaningfully.
| bluGill wrote:
| TPMS has been law in the US since 2007. People might be
| driving around with under inflated tires, but there is a
| light on if they are.
| bkanber wrote:
| My cold tire pressure is supposed to be 33PSI, my TPMS
| doesn't alert until it's below 28PSI, so there is a
| significant delta still.
|
| The TREAD law does not specify when TPMS must alert,
| other than the tire being 'significantly underinflated'.
| loeg wrote:
| The NHTSA has determined that the requirement is that
| TPMS alerts for 25% underinflation across any combination
| of tires, or 30% underinflation in a single tire.[1]
| Originally they wanted 20-25%, but determined that cheap
| TPMS sensors were not good enough to meet that threshold
| and did not want to impose the cost of better sensors.
|
| [1]: https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TP
| MSfinalr...
| loeg wrote:
| TPMS doesn't alert until tires are something like 25-30%
| under pressure, which is pretty severe.[1]
|
| [1]: https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TP
| MSfinalr... (page 10)
| bkanber wrote:
| Overinflated tires will always have better economy than
| underinflated, all other things being equal. My guess is
| the average vehicle owner could improve overall fuel
| economy by about 0.5-1.0% by making sure their tires are at
| the correct pressure.
| kbenson wrote:
| So, my thought when I said that was back when Obama
| mentioned keeping tires inflated correctly and getting
| tuneups to reduce oil consumption, and looking into that
| lead to this[1], which puts it at 0.6% on average, but up
| to 3% in specific cases.
|
| So I guess the question is how does 0.6% fuel economy
| loss on average for current tires compare to the loss in
| efficiency for using a Tweel, but according to some data
| from Michelin here[2], it looks like they're actually
| projecting them to be _more_ efficient than current
| tires? I didn 't read through the whole analysis, so I'm
| not sure, but that's what Table 7 looks like to me at a
| cursory glance and reading a few paragraphs in that
| section.
|
| 1: https://www.fueleconomy.gov/feg/maintain.jsp
|
| 2: https://manufacturing.gatech.edu/sites/default/files/u
| ploads...
| bkanber wrote:
| Funny -- I presented a paper at that very same
| conference! Mine was 2011-01-0755.
|
| The money shot is here. Note that '5.5 kg/ton' refers to
| the rolling resistance of the tire.
|
| > At this point the 5.5 kg/ton value is still only a
| design target, and this study serves mainly to confirm
| the environmental value of achieving that target.
|
| Essentially, this conclusion is tautological. "If there
| were a tweel that had better rolling resistance than the
| best pneumatic tire on the market, then it will have a
| better fuel economy and environmental impact." Obviously!
|
| I _seriously_ doubt Michelin 's tweel is anywhere _close_
| to that 5.5 kg /T mark. It's more likely something like
| 12 kg/T.
|
| The purpose of this particular paper is not to show that
| tweels are better environmentally, it is to show an
| analytical framework for calculating the full-lifecycle
| environmental impact of tweels vs tires. Sort of like a
| "here are the equations, plug in real numbers later" kind
| of thing.
| kbenson wrote:
| Ah, nice to know, and thanks for giving a professional's
| assessment of what's being said. :)
| bkanber wrote:
| :) Not a problem! Your experience hangs a lantern on one
| of the problems in academia.
|
| The authors of that paper did not intend to mislead --
| this paper was published in 2011, likely written in 2010,
| only a handful of years after Michelin's unveiling of
| their gen 1 tweel design. To me, having been in the
| authors' position, I can easily tell what the true
| purpose of the paper actually was (the analytical
| procedure). But the authors had a secondary purpose
| driven by 'hype', almost, you could even call it click-
| bait: they wanted to make the tweel exciting so that
| _other researchers would get interested in it and
| continue the work_. One way to do that is by showing,
| from a materials perspective, that it is theoretically
| possible to design a tweel with a low rolling resistance,
| and given that, it 's possible that tweels will be better
| for the environment over the full-lifecycle, including
| manufacturing and materials. And sure, this absolutely
| did/does deserve more research. However, the other issues
| with tweels, like NVH/comfort/etc, were 'out-of-scope'
| for that paper, and so they ignored those. Solving for
| those issues is what makes that 5.5 kg/T figure
| difficult/possibly impossible to attain.
|
| When these papers are confined to academia, it all works
| out, because most of the people who read your paper are
| other people who are writing papers, and they get it. But
| once these types of papers are picked up by the
| press/media/general populous, they can be very quickly
| misinterpreted!
|
| (To be clear, you didn't do anything wrong here, I'm just
| griping a bit about academia and pretending like I'm
| 'adding context' ;)
| kbenson wrote:
| Yeah, I'm totally aware of how hard it is to accurately
| assess and relate info from a technical paper without
| experience in the industry, which is why I try to make
| sure I express how little confidence I have in how I'm
| relating that info, given I very rarely have time to
| actually dive deep into a paper when looking something up
| like this.
|
| In some ways what you describe is a very common larger
| problem. When you want to promote something (whether it
| be because of financial or more altruistic reasons), its
| hard (possibly impossible) to walk the fine line for all
| people between accurately relaying information and
| convincing people of something less factual (such as
| "this is cool and we should look into it more"), namely
| because different audiences' relative experience in the
| area will mean they won't recognize where that line is in
| many cases.
|
| For example, at exactly what point does a website or
| description for some open source project move from purely
| descriptive explanations of what it can do to promotion
| about why it's cool and why you should try it? People
| with different experience in the domain it's in will have
| difference experiences ready that info. The neophyte and
| the layman will interpret the statements differently.
| jacquesm wrote:
| I hope the open sides will be closed up because those are going
| to be grime collectors if exposed to the weather. I'd expect them
| to be full of crap before the first month of use is out.
|
| Edit: apparently they are.
| agys wrote:
| The 3rd illustration displayed (the one that accompanies the
| claim "A smaller environmental footprint") is extremely
| enigmatic...
| j56no wrote:
| shouldnt they be "closed" laterally for aerodynamics, to block
| dirt and snow from getting stuck inside? guess these will collect
| dirt 100 times more than regular tires no?
|
| update: similar questions here
| https://m.youtube.com/watch?time_continue=206&v=sc8ghIqKqnI&...
| hirvi74 wrote:
| They will have walls, this is just a demo model to show the
| internals.
| loufe wrote:
| In another comment it was mentioned that there will doubtlessly
| be "sidewalls" on actual airless tires, and that the exposed
| ones shown on this page are just for show. I admit that makes a
| lot of sense given your point about dirt/rocks entering in and
| effecting the absorption effect of the honeycomb.
| nickpinkston wrote:
| These being around forever, but not being released, I wonder how
| much of why this is happening now is because they're finally
| coming off patent?
| tootie wrote:
| "Every year, 20%* of tires are discarded as scrap "
|
| Really? They cite a survey, but don't link to it.
| Ensorceled wrote:
| The number doesn't seem to far off. I have summer and winter
| tires, replace them every 6-7 years. Lots of people drive more
| than I do.
| lrem wrote:
| I don't drive that much and still feel that changing tyres
| every five years is pushing it.
| aidenn0 wrote:
| You misunderstood; the claim is that 20% of the tires that are
| discarded are due to punctures or improper inflation.
|
| 12% of the tires that are discarded are discarded due to
| punctures or blowouts and 8% of tires that are discarded are
| discarded due to uneven wear caused by improper inflation.
| thinkling wrote:
| Tires are usually rated for 40 ,000 to 60,000 miles. Americans
| drive 13,500 miles per on average[1]. That would cause tires to
| be replaced on average after ~4 years. So yeah, seems
| believable.
|
| [1] https://www.fhwa.dot.gov/ohim/onh00/bar8.htm
| aidenn0 wrote:
| I have never gotten the rated tread lifetime on a tire. I've
| gone through maybe 60 tires in my lifetime and none of them
| were replaced due to punctures (I had one repairable
| puncture). Partly because 90% of my miles are stop/go rather
| than cruising.
| EvanAnderson wrote:
| This design looks to be much less mosquito-breeding-friendly than
| traditional tires at least. I was shocked when I learned how much
| "help" discarded tires lend to mosquito breeding.
| _fat_santa wrote:
| I wonder, how would airless tires be able to handle offroading?
| On the one hand they seem like the perfect candidate as running
| over a rock or stick won't cause the tire to puncture. But on the
| other hand you loose the ability to air down the tire for more
| traction.
| goodmachine wrote:
| Fun fact, almost half of particulate road pollution comes from
| conventional tyres.
|
| Not clear whether these new airless tyres will help or worsen
| that. More resistance = more wear, I would assume. Anyone?
|
| https://www.imperial.ac.uk/news/195595/worlds-first-device-c...
| andylynch wrote:
| I head looked at these before, and only now noticed they that
| talk about retreading/ recharging treads by 3D printing- this
| doesn't directly address the particulate issue but is a very
| interesting idea for reducing the waste from worn tyres more
| generally.
| jrootabega wrote:
| I wonder how hot those spokes get at speed.
| andreygrehov wrote:
| What I like about companies like Apple is when they release
| something, they explicitly say: "This product will be available
| in stores starting Oct 15". On Oct 15, you go to apple.com and
| buy the product online. Done. I can't even count how many years
| I've heard about airless tires being developed.
| skywal_l wrote:
| Is it only hype? What about road adherence, endurance, etc. As
| long as I don't see independent assessments by car journalists,
| I'll reserve my judgement.
|
| But if they live up to the hype, it will be a game changer
| indeed.
| jcims wrote:
| IIRC they have some interesting attributes. Lateral stiffness
| is incredibly high, but IIRC rolling resistance is higher and
| they are quite a bit heavier than standard tires. Seems like
| there might be some interesting capabilities to pump air one
| way or the other for aero purposes.
| wayoutthere wrote:
| From my understanding, the dealbreaker is that these tires are
| incredibly noisy at highway speeds.
| x62Bh7948f wrote:
| I remember reading about airless tires back when I was in high
| school and it seemed like the concept was ready for mass
| production in a couple years. That was around 2004~5 ish. I
| wonder how much has changed and how close are others, like
| bridgestone.
| jpm_sd wrote:
| Would these work on Mars rovers too?
| bkanber wrote:
| Mars rovers already use tires like these.
| amelius wrote:
| Or how about bicycles?
| jaclaz wrote:
| Superwheels, discussed here (but tyres remain conventional):
|
| https://news.ycombinator.com/item?id=25158215
| dingaling wrote:
| Spring tyres were used on bicycles in World War One
|
| https://onlinebicyclemuseum.co.uk/ww1-german-bicycles/
| bkanber wrote:
| Tweels are _probably_ too heavy to be viable on bicycles.
| amelius wrote:
| https://www.bridgestone.com/corporate/news/2017041701.html
| bkanber wrote:
| > The companies will advance feasibility studies seeking
| to make this new tire available in market by 2019.
|
| Given that I haven't seen tweels for bicycles yet, I
| assume the feasibility studies did not go well.
|
| It also looks like they also announced that bicycle
| tweels were 'coming soon' nearly two years ago:
| https://jalopnik.com/bridgestone-says-airless-tires-are-
| comi...
| bb123 wrote:
| I always wonder how these things would stand up to stones getting
| caught in between the rubber "spokes".
| bmitc wrote:
| I thought that at first too but then wondered if the views are
| simply a cross section, where the final tire will have that
| part covered as a regular tire would with rubber.
| mabub24 wrote:
| Completely guessing, but I wonder if they designed the "spoke"
| baffles to pinch in under the load and thus expel any stones
| that might fit between them, like a pebble squeezed between
| your two fingers and shooting out.
| rbanffy wrote:
| A pebble shooting out of the upper side of a tire of a car at
| 250 km/h is probably as bad as a bullet. Probably worse.
| kadoban wrote:
| So about the same as a pebble that gets stuck in treads or
| kicked up by same? Definitely better than a bullet though
| just by nature of lower speed, what it's made of and
| because of its poor aerodynamics.
| rbanffy wrote:
| These spokes seem to be able to fit larger pebbles that
| may be launched from the side of the wheel and escape the
| wheel well.
| bkanber wrote:
| These tires have sidewalls, the spokes are not exposed. Without
| sidewalls these tires would be very loud on the highway, and
| would have a much higher rolling resistance.
| TimTheTinker wrote:
| I don't think that part of the tire is open to the outside --
| you're seeing a cross-section in the pictures and video.
| drewmol wrote:
| For airless tires I've used a 4x4 (quad), the tires are open
| on the side just like these images.
| bkanber wrote:
| For a passenger vehicle application, these tweels will have
| sidewalls. You don't hit highway speeds on your quad and
| that makes all the difference.
|
| In fact you can see that the photo of the EV on their site
| has sidewalls.
| [deleted]
| [deleted]
| AtlasBarfed wrote:
| I'm unimpressed with their pilot location choice. Las Vegas?
|
| Chicago or NYC would be much more of a proper test with potholes,
| humidity, potholes, temperature, potholes, and precipitation. Did
| I mention potholes.
| einpoklum wrote:
| > Airless technology will drastically reduce the number of tires
| that are scrapped because of punctures.
|
| Well, maybe, but don't these new tires use more rubber instead of
| air? In which case they will actually increase the amount of
| discarded tires? Also, what about the recycling potential of
| these tires?
|
| I'm not an automotive buff, but this claim of being "good for the
| environment" sounds like just empty marketing talk.
| bborud wrote:
| I wonder what the speed rating of these will be.
|
| (I'd guess they would overheat _really_ fast if you drove them
| even moderately fast, plus the inertia would be pretty insane?)
| syncsynchalt wrote:
| The magic of the pneumatic (air-filled) tire is that the entire
| air-filled space of the tire acts to absorb shock and vibration
| from the road surface.
|
| Airless tires give up this advantage, and only the tire structure
| between the wheel and contact patch are available to do the same
| work.
|
| The result is always a heavier tire that is a harsher ride. All
| the materials science in the world can't and won't find a
| solution to this. You can safely ignore any airless system for
| all but the most specialized applications.
| elif wrote:
| or a country that has its roads together like japan and china
| sfobiab wrote:
| Have you driven around within China much?
| KennyBlanken wrote:
| The result is also always an efficiency loss. Periodically
| solid bike tires become faddish and it's like pedaling a bike
| made of lead.
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