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Former automotive engineer chiming in. "Tweels" have been around a long time, but have always failed in terms of "NVH" (noise, vibration, harshness). Michelin i
by bkanber 5y ago
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.)
- 725686 5y agoMaybe the noise they generate is good for EVs which are dangerously quiet for pedestrians?
- smilekzs 5y agoValid 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 5y agoAnd effective at rattling off any untorqued/loose nuts/bolts.
- agumonkey 5y agoSome 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 5y agoI thought it was a plastic valence rubbing on something.
- agumonkey 5y agonah it's on purpose https://www.youtube.com/watch?v=mNkGD_Sryxg https://www.youtube.com/watch?v=mNkGD_Sryxg
- arecurrence 5y agoHybrids 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 5y agoEvery EV sold today must make noise at low speeds.[1] 1. https://en.wikipedia.org/wiki/Electric_vehicle_warning_sounds https://en.wikipedia.org/wiki/Electric_vehicle_warning_sound...
- speedgoose 5y agoYou 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.
- dharmab 5y agoIronically NVH is even more important in EVs since the engine noise no longer drowns out unpleasant sounds like fan motors, hums, squeaks/rattles
- ofou 5y agoNoise is not good, ever.
- Pxtl 5y agoEVs don't have space to store a donut so an airless system that can't deflate would be useful.
- djrogers 5y agoThat'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 5y agoI 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.
- slownews45 5y agoThis does still look to be a marketing excercise for now - I see no product availability to market in 6-12 months still.
- belter 5y agoFor utility vehicles on sale now, it seems: https://tweel.michelinman.com/michelin-tweel-family-of-products https://tweel.michelinman.com/michelin-tweel-family-of-produ...
- slownews45 5y agoThat 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?).
- 8ytecoder 5y agoDon'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 5y agoBridgestone said bike tweels were close 4 years ago, and then again 2 years ago... I won't hold my breath! :)
- 8ytecoder 5y agoTannus 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.
- lost-found 5y agoMichelin is by far the market leader in tires, especially compared to Bridgestone.
- LargoLasskhyfv 5y agoReally? 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 4€ 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.
- 8ytecoder 5y agoYou 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.
- moneywoes 5y agoIs there a reason this technology is not used on bikes which weigh a lot less?
- djrogers 5y agoBecause 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.
- ddlsmurf 5y agoComplete 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 ?
- bkanber 5y agoAt some point they will be viable... whether this is that point or not is yet to be seen.
- OnlineGladiator 5y ago> At some point they will be viable Why do you assume this?
- gregoriol 5y agoBecause at some point we used wood for wheels?
- _jal 5y agoYou 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 5y agoHmm, not the worst idea. But who makes wood tires for bikes nowadays? And oh God, the splinters :D
- JAlexoid 5y agoWe still do use wood for wheels... So...
- dahfizz 5y agoHow does wood --> inflated rubber imply inflated rubber--> airless rubber? I don't see any logic in that.
- andrewblossom 5y agoCompact 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 5y agoThe 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.
- KptMarchewa 5y agoEVs are usually much heavier than gas cars.
- bkanber 5y agoFor the same form factor, yes that's true.
- ggreer 5y agoI 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 https://en.wikipedia.org/wiki/Tesla_Model_3 2. https://www.caranddriver.com/bmw/3-series/specs https://www.caranddriver.com/bmw/3-series/specs
- mitigating 5y agoBMW 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 5y agoI picked a gas car of comparable size. The Civic and Golf are much smaller than the Model 3.
- kube-system 5y agoThe 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.
- flurie 5y agoEVs are quite heavy for their footprint due to the weight of the batteries.
- gibolt 5y agoThis 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.
- deleted 5y ago[deleted]
- tromp 5y agoThere are exceptions though like the upcoming Aptera which only weighs around 800 kg even with a large range.
- _ea1k 5y agoUnfortunately, 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.
- kube-system 5y agoI'll believe it when it happens. Aptera has gone out of business more times than they have released a production car.
- stouset 5y agoI 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.
- brightball 5y agoI remember Michelin talking about these before but seem to recall that the biggest impediment was cannibalization concerns from existing departments.
- throwaway803453 5y agoDoes 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.
- KennyBlanken 5y agoThe 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.
- bkanber 5y agoFor 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.
- deleted 5y ago[deleted]
- noobermin 5y agoSorry 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 5y agoWhile 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-sales-since-1951/ https://www.statista.com/statistics/199981/us-car-and-truck-...
- thefounder 5y agoNah...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.
- fischert 5y agoThis 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.
- discreteevent 5y ago> 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.
- rolleiflex 5y agoDo 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.
- harambae 5y agoI wonder this myself. I'm not sure the technology is ready for street bike speeds, but some of the speeds you do on a dirtbike with tight turns and technical terrains.. maybe. https://www.rockymountainatvmc.com/tires-and-wheels/michelin-bib-mousse-foam-tube-p https://www.rockymountainatvmc.com/tires-and-wheels/michelin... An "equivalent psi" of 13, which is basically what I run my dirtbike at anyway in the New Hampshire forest trails. Although this is slightly different since it replaces the tube not the whole tire.
- tibbydudeza 5y agoAlso don't you need to change the traditional car suspension system (McPherson struts, wishbones, shock absorbers etc ... ) to even use these tyres ???.
- toss1 5y agoI'm interested in how they maintain balance if mud or ice gets in some of the gaps. Are they just shaped so that the dynamics while rolling flex the ribs & tread in such a way as to expel any such contaminants?
- anonu 5y agoI understood this was a tough problem to solve when I swapped my hard-to-inflate scooter tires with some cheap tweels. NVH, even at 15MPH, is real. For anyone wanting to do this to their electric scooters, dont... until Michelin makes a scooter form-factor wheel I suppose.