Michelin Airless • Hacker News Board

Re: Michelin Airless

#71

Post by syncsynchalt » Thu, Oct 14, 2021, 3:57 PM UTC

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.

Re: Michelin Airless

#72

Post by ggreer » Thu, Oct 14, 2021, 3:58 PM UTC

mitigating wrote: post #69

ggreer wrote: post #66

Earlier quoted context omitted.

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) driv…

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.

I picked a gas car of comparable size. The Civic and Golf are much smaller than the Model 3.

Re: Michelin Airless

#73

Post by zubiaur » Thu, Oct 14, 2021, 3:58 PM UTC

_fat_santa wrote: post #48

intrasight wrote: post #34

Earlier quoted context omitted.

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 w…

> 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 put…

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.

Re: Michelin Airless

#74

Post by OnlineGladiator » Thu, Oct 14, 2021, 3:58 PM UTC

bkanber wrote: post #26

ddlsmurf wrote: post #20

Earlier quoted context omitted.

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 ?

At some point they will be viable... whether this is that point or not is yet to be seen.

> At some point they will be viable

Why do you assume this?

Re: Michelin Airless

#75

Post by modeless » Thu, Oct 14, 2021, 3:59 PM UTC

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.

Re: Michelin Airless

#76

Post by smilekzs » Thu, Oct 14, 2021, 3:59 PM UTC

725686 wrote: post #67

bkanber wrote: post #13

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. (…

Maybe the noise they generate is good for EVs which are dangerously quiet for pedestrians?

Valid point, although pedestrian safety is mostly discussed in the low-to-mid-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.

Re: Michelin Airless

#77

Post by syncsynchalt » Thu, Oct 14, 2021, 3:59 PM UTC

bkanber wrote: post #46

ur-whale wrote: post #21

Ride comfort on those?

Ride comfort on tweels has historically been poor. But Michelin seems to be claiming they've solved that problem for this generation.

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.

Re: Michelin Airless

#78

Post by sgarrity » Thu, Oct 14, 2021, 3:59 PM UTC

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)

Re: Michelin Airless

#79

Post by agumonkey » Thu, Oct 14, 2021, 4:00 PM UTC

725686 wrote: post #67

bkanber wrote: post #13

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. (…

Maybe the noise they generate is good for EVs which are dangerously quiet for pedestrians?

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.

Re: Michelin Airless

#80

Post by ggreer » Thu, Oct 14, 2021, 4:00 PM UTC

725686 wrote: post #67

bkanber wrote: post #13

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. (…

Maybe the noise they generate is good for EVs which are dangerously quiet for pedestrians?

Every EV sold today must make noise at low speeds.[1]

1. https://en.wikipedia.org/wiki/Electric_vehicle_warning_sound...