Friday 10th February 2006

Michelin rolls out airless tyre

Tweel offers vision of maintenance-free tyres

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Michelin wheeled out its airless tyre at the North American Motor Show yesterday, describing it this time as "the first real-world fitment" (see link below for earlier story). And it might coming to a car near you soon.

Michelin's Tweel is in production and available as an enhancement for future iBOT mobility systems for the disabled. Invented by Dean Kamen, the iBOT mobility device can climb stairs and navigate uneven terrain, offering mobility freedom impossible with traditional wheelchairs.

Beyond these first real-world applications, Michelin said it has additional projects for Tweel on construction skidsteers and a variety of military vehicles.

The most intriguing application may be Michelin's early prototype Tweel fitment for passenger cars. The mobility company released a video of Tweel running under an Audi A4.

"The Tweel automotive application, as demonstrated on the Audi, is definitely a concept, a stretch application with strong future potential," said Michelin's research boss Terry Gettys. "Our concentration is to enter the market with lower-speed, lower-weight Tweel applications. What we learn from our early successes will be applied to Tweel fitments for passenger cars and beyond."

What is a Tweel?

The heart of Tweel innovation is its simple-looking hub and spoke design that replaces the need for air pressure while delivering performance that Michelin claimed is akin to that of pneumatic tyres. The flexible spokes are fused with a flexible wheel that deforms to absorb shock and rebound easily. Without the air needed by conventional tyres, Tweel still delivers pneumatic-like performance in weight-carrying capacity, ride comfort, and the ability to envelop road hazards, reckoned the company.

Michelin said it had found that it can tune Tweel performances independently of each other, which is a significant change from conventional tyres. This means that vertical stiffness (which primarily affects ride comfort) and lateral stiffness (which affects handling and cornering) can both be optimised, improving performance and enabling new performances not possible for current inflated tires.

The Tweel prototype, demonstrated on the Audi A4, is within five per cent of the rolling resistance and mass levels of standard tyres so fuel economy should be almost unaffected, said Michelin. Michelin said it had increased the lateral stiffness by a factor of five, making the prototype unusually responsive in its handling.

Future of Tweel technology

For Michelin, Tweel is a long-term vision that represents the next step in a long path of industry-changing innovations. The lessons learned from Tweel research are being applied to improve conventional tyre performances, according to Michelin. In the future, Tweel may reinvent the way that vehicles move. Tyre maintenance and balancing between traction and comfort could all fade into memory, said the company.

• PH story: Michelin reveals tyred thinking

[annodomini2]

Would be interesting to see average lap times between the A4 on Tweel and on conventional tyres (manufacturers standard fit), assuming you could get an equal comparison.

And vertical g difference (i.e. hitting bumps) between the 2.

[dinkel]

Optically that looks pretty stupid . . . and what if something gets stuck in the tire: slingshot or messed up arch, or worse.

Smart idea though. An intergrated wheel-rim combi would be nice. I can see the benifits for trucks and other pro-used vehicles.

[scared but happy]

I presume the final model will have filled in sides as I suspect the demonstation models have open sides to show the workings. I also expect that to create a one hell of spray when going through puddles.

Great idea though. I just wonder if you can retro fit the tyres onto standard rims? Also as the 'pressure' remains the same hot/cold that means tyre wear should be reduced.

But thinking about it for a minute if the tyre maintains itself would they be doing themselfs out of a few sales?

[ubergreg]

To gain mainstream market acceptance (at least initially) I'm sure it wouldn't be much of a stretch for the manufacturer to 'clothe' the tweel spokes to look like a conventional tyre. It's probably also possible for them to introduce a low-profile size - though I wonder how far the ride would deteriorate.

At this point, I'm wondering how the costs would compare to an conventional radial or run-flat tyre... sounds like good technology to me.

[Code Monkey]

Concept cars will be coming soon though with the side walls removed, to allow them a total rubber band look, imagine the side deformable section of the wheel in the same colour as the wheel would make a micra look like it was fully pimped running on dubs, i think thats the correct phrase

[V8YEA]

I assume Michelin will have thought about skinning the sidewall to prevent damage to the vanes.This would make it look more like a conventional tyre as the majority are averse to a change as radical as this.It would also keep potentially harmful debris out.
Are we going to get a choice of wheel design as well ? As far as tyre retailers are concerned this is a stocking nightmare ,if the item comes as a one piece non divisable unit,what about all the different PCD,s,offsets etc,required to have a chance of selling from stock.Also if you have to buy a wheel every time you buy a tyre its going to get expensive,can you trade in your worn tweel to be retyred ?
Yes it would be an end to punctures but when was the last time you had one ???

[cdp]

V8YEA said:

I assume Michelin will have thought about skinning the sidewall to prevent damage to the vanes.This would make it look more like a conventional tyre as the majority are averse to a change as radical as this.It would also keep potentially harmful debris out. Are we going to get a choice of wheel design as well ? As far as tyre retailers are concerned this is a stocking nightmare ,if the item comes as a one piece non divisable unit,what about all the different PCD,s,offsets etc,required to have a chance of selling from stock.Also if you have to buy a wheel every time you buy a tyre its going to get expensive,can you trade in your worn tweel to be retyred ? Yes it would be an end to punctures but when was the last time you had one ???

I get at least one puncture a year. I wouldn't buy a car with a space saver tyre and I'll take a look at the jack on my next car as the Vauxhall supplied item is useless enough to be dangerous.

[NormanD]

It's not April the 1st is it?

[oagent]

Having had a puncture this morning on my way to work im all for the airless tyre!

[Ruaraidh_Gamma]

Have they solved the thrumming issue yet?

The radial ribs passing the contact patch cause a humming road noise that varies with speed. (think proper off road tyre type hum)

Cheers,

Ruaraidh

[AtomicRex]

OK so its looks like it will work well with the forces acting towards the centre, but what about the lateral forces?

[Dodgey_Rog]

http://dl3.dumpalink.com/media/8YggDpXu6VF5/P9Ju4iGi

There's a demonstration video if you wanna see it action. Interesting stuff really.

The guy from Michelin is a really really interesting guy.................

>> Edited by Dodgey_Rog on Friday 10th February 14:04

[mybrainhurts]

If you think a Tweel's good, just wait 'til they unleash the Twonk....

[whatever]

oagent said:

Having had a puncture this morning on my way to work im all for the airless tyre!

(I know it's not a joking matter but...)
You've already got one!

[Yugguy]

These have been around for a while now, can't see it myself, it's a very radical change and ugly as well. Also as the trend now is for bigger and bigger wheels with smaller and smaller profile tyres I don't think the tweel would be able to be marketed now as the actual solid wheel part is relatively small compared to the overall size of the unit.

[sprinter885]

I can see the bad guys laughing all the way FROM the bank. Picture the scene of crooks chasing off in your PAJ with loot in boot & a STINGER thrown out in front. Hmmmmm !!!

[m1spw]

Dodgey_Rog said:

http://dl3.dumpalink.com/media/8YggDpXu6VF5/P9Ju4iGi There's a demonstration video if you wanna see it action. Interesting stuff really. The guy from Michelin is a really really interesting guy................. >> Edited by Dodgey_Rog on Friday 10th February 14:04

Whats the quad bike type thing in that film?

[whatever]

Given the apparently reduced size of the "rim" here, then it's going to be impossible to fit in a large diameter brake disc, isn't it? Isn't that one of the key benefits of the larger rim?

[Parrot of Doom]

I think its a great idea personally. And the clear sides are just to show the workings, they won't be selling them like that.

[will ferrari]

Wicked stuff, might put some on future concepts I design, as for stuff getting stuck n them, doesn't happen with car wheel spokes so doubt there is an issue and if they do cover the sides, whats the point, they won't look cool, which is surely the whole point in my opinion.