Michelin & GM Join for Final Development of Airless Tire for EVs & Other Vehicles

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Texas22Step

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Michelin at the "Movin' On Summit" in Montreal on June 4 announced its future airless tire currently called "UPTIS" or "Unique Puncture-proof TIre System" and a testing program to begin on GM's Chevy Bolt EV's later this year in Michigan.

Here are a couple photos of one of the prototype tires on a Bolt, plus the Michelin press release and a couple of links for more information.

Maybe run-flat tires will be obsoleted by this concept, if it reaches production at an affordable price (that is to say, Michelin & GM are not full of just hot air on this idea).

For more info see: https://www.autoblog.com/2019/06/04/michelin-uptis-2024-chevy-bolt-airless-tire-test/ and https://michelinmedia.com/michelin-uptis/?
PrototypeWheels04.webp
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KentuckyKen said:
I wonder what the tread life and grip are on those, and how long it takes to develop a flat spot when parked vs regular tires. And will they be low rolling resistance?
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Their rolling resistance will decrease as the open cells fill up with mud entering from the side. However, I imagine that when the mud dries out, it will crumble and exit the tire. It won't be enough to detail your wheels (as if I ever do that)--soon you'll have to detail the insides of your tires, too!
 
insightman said:
Their rolling resistance will decrease as the open cells fill up with mud entering from the side. However, I imagine that when the mud dries out, it will crumble and exit the tire. It won't be enough to detail your wheels (as if I ever do that)--soon you'll have to detail the insides of your tires, too!
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Yes, I initially had this exact same concern too. But, on looking at some of the available info on the Michelin web site and other places, it is apparent that the tires shown on the Bolt are "cut-away" demo tires to show the interior construction and how these tires would work. I don't think sidewalls of some sort will go away. Take a look at this video to better see how it is all supposed to work:
 
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Texas22Step said:
But, on looking at some of the available info on the Michelin web site and other places, it is apparent that the tires shown on the Bolt are "cut-away" demo tires to show the interior construction and how these tires would work. I don't think sidewalls of some sort will go away. Take a look at this video to better see how it is all supposed to work
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I watched the video and went to Michelin's Uptis website to read their FAQ and download their Visual Assets zip file. I don't see any images that include a sidewall on this tire. If there was a sidewall, wouldn't each cell need a vent to allow air to go in and out as the tire flexes?
 
insightman said:
If there was a sidewall, wouldn't each cell need a vent to allow air to go in and out as the tire flexes?
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That certainly is a logical question. I think the video animation shows a sort of “spider web” that encloses the sidewall, but even that seemingly would allow road dirt, ice & snow, etc. to accumulate.... Since they say GM will do road testing on a fleet of Bolts in Michigan starting late this year (winter), we will see what production design(s) they have in mind then, I suppose.
 
Looks like they would work great for a lunar rover. I guess we'll have to wait and see how well they work for us earthlings.
 
Ugly and a non-starter for a Michigan winter with snow/ice. Even mud would throw off the balance. This idea needs work.
 
rodeknyt said:
There isn't any vent on a normal tire to accommodate flex, why would that be needed on this?
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A normal tire counts on contained air to maintain its shape. If each cell in the Uptis tire was enclosed by a sidewall then the air-tight cell wouldn't be able to flex the way it can without a sidewall. If the walls of the cell were weakened to compensate for stiffness of the air-tight cell, then we're back to a tire that can go flat if the sidewall is breached. Then there's the issue of heat introduced by the flexing of the cell walls; a sidewall would not permit air-cooling.
 
How about sidewalls AND holes between all the partitions???
Then no debris can get in and air just moves around between the cells as the ones on the bottom compress.
Just not sure about heat build up and if sidewalls will allow the partitions to flex as they do in the ones with no sidewalls on ATVs and mowers.
I bet they are still a work in progress and won’t be ready for automotive use at reasonable prices and tread life, etc. for quite a while.
 
KentuckyKen said:
How about sidewalls AND holes between all the partitions???
Then no debris can get in and air just moves around between the cells as the ones on the bottom compress.
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Then just one big vent to let the air in and out--and heat out--of the tire? If there's no vent, then it's just a pneumatic tire, isn't it?
 
Technically, but you could leave it unpressurized (at atmospheric pressure) so it wouldn’t depend on being aired up to function and would retain its run flat properties?
Hey, what do all those experts At Michelin know that we don’t? Can’t we just plant some rubber trees in the backyard and start making our own tires.
Haha!!
 
Texas22Step said:
Michelin at the "Movin' On Summit" in Montreal on June 4 announced its future airless tire currently called "UPTIS" or "Unique Puncture-proof TIre System" and a testing program to begin on GM's Chevy Bolt EV's later this year in Michigan.
Click to expand...

Looks like a fabulous advancement, if they can make them last as long as regular tires at a competitive price!

Imagine never having to worry about having a flat tire for the rest of your life. Of course, just like almost anything in constant use, it will wear out eventually. But IMHO this could be quite and improvement over existing tires!
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KentuckyKen said:
Technically, but you could leave it unpressurized (at atmospheric pressure) so it wouldn’t depend on being aired up to function and would retain its run flat properties?
Hey, what do all those experts At Michelin know that we don’t? Can’t we just plant some rubber trees in the backyard and start making our own tires.
Haha!!
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Ideally, it should allow air to pass in and out of the tire, altho only slowly, to prevent heat buildup from over-pressurizing the tire. One problem with pneumatic tires is they need to be maintained at an exact pressure for best MPG/ energy efficiency, but as the tire heats up from driving, the air inside expands. These non-inflating ("airless") tires offer the possibility of eliminating that disadvantage.

The question is, where do you put vent holes that will prevent mud and debris from entering? Maybe holes in the rim? I dunno, there's probably some clever solution which escapes me at the moment.

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Personally, I doubt that passing air between cells should be an engineering challenge. Just make the partitions between cells as full of holes as Swiss cheese; problem solved. Air should be able to pass from one to another so easily that no significant amount of compression will happen, and thus no appreciable heating of the air.
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