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Michelin Airless

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Re: Michelin Airless

#161

Post by kwhitefoot »

Yizahi wrote: post #16

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 ar…

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.

Re: Michelin Airless

#162

Post by beauzero »

xxpor wrote: post #97
arghwhat wrote: post #82

Earlier quoted context omitted.

A lot of heavy equipment drives around with water-filled tires, so it's already there. Definitely not what you meant though.

Hmm, why water filled? I can't think of any advantages, but can think of downsides such as a massive increase in unsprung weight.

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).

Re: Michelin Airless

#163

Post by bkanber »

bluGill wrote: post #152
kbenson wrote: post #64

Earlier quoted context omitted.

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 j…

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.

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'.

Re: Michelin Airless

#164

Post by karambahh »

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 ;)

Re: Michelin Airless

#165

Post by bkanber »

8ytecoder wrote: post #157
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. (…

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.

Bridgestone said bike tweels were close 4 years ago, and then again 2 years ago... I won't hold my breath! :)

Re: Michelin Airless

#166

Post by legulere »

arghwhat wrote: post #82
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 ?

A lot of heavy equipment drives around with water-filled tires, so it's already there. Definitely not what you meant though.

Also trains drive around with solid metal tires.

Re: Michelin Airless

#168

Post by bkanber »

dsr_ wrote: post #128
hollander wrote: post #116

Earlier quoted context omitted.

I use nitro oxygen in my tyres. Pressure problems are gone.

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?

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).

Re: Michelin Airless

#169

Post by bkanber »

throwaway803453 wrote: post #93
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. (…

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.

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.

Re: Michelin Airless

#170

Post by 8ytecoder »

bkanber wrote: post #165
8ytecoder wrote: post #157

Earlier quoted context omitted.

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.

Bridgestone said bike tweels were close 4 years ago, and then again 2 years ago... I won't hold my breath! :)

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.
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