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Offline mondi

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They played with these a few years ago, didn't think they got too far with them?

Quote
In combat numerous Humvee military vehicles equipped with standard issue "run flat" tires have been tragically immobilized by IEDs (Improvised Explosive Devices). So, the military wants an alternative tire that can support the additional weight of add-on armor, survive an IED attack, and still speed away at up to 50 mph.
Resilient Technologies and Wisconsin-Madison's Polymer Engineering Center have developed a "non-pneumatic tire" (without air) that meet these requirements.

We've seen this type of wheel before with the Michelin Tweel. In fact, the Tweel was one of several airless tires studied, but developers concluded that mother nature's honeycomb design was more suitable as it provided the most realistic ride feel of pneumatic tires, according to the developers.

"The goal was to reduce the variation in the stiffness of the tire, to make it transmit loads uniformly and become more homogenous," said mechanical engineering professor Tim Osswald. "And the best design, as nature gives it to us, is really the honeycomb."

Furthermore, other benefits of the design geometry are reduced noise and heat levels while in motion.

The honeycomb tires starts deliveries in 2011 with prices expected to be comparable if not less than current tires.



Offline AshSimmonds

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Wonder how honeycomb would cope on a profile like this...


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Offline mondi

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Wonder how honeycomb would cope on a profile like this...


Bloody hell, is there any room for the Air???  :D

These honeycomb things will only have a limited application unless the technology gets better, as I see it.
The article states around 50mph limit on the speed, I would not like to be traveling at 50mph on these things.
I can't see how these will be able to be used for racing or performance cars. The side ways flex just wouldn't happen.

Sure, they would be good for the military as bullet proof types and maybe ATVs but other than that I just don't see how they could work even on a normal road car.

Michilen played with something like this a few years ago but I haven't seen much about them until this article came up.



Offline 993tits

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I can't see how these will be able to be used for racing or performance cars. The side ways flex just wouldn't happen.

The whole concept of a racing tyre is to get rid of the "side ways flex"................there is almost none in an R-spec tyre and you would be hard pressed to register any in a slick tyre. One of the things that destroys a road tyre, even a mega road tyre from one of our supercars, is the side wall flexes too much under the stress loads that are in evidence on the circuit.

The concept is that the tyre uses rubber compounds to generate mechanical grip and super stiff sidewalls to enable the rubber to generate it's "stickiness" on the contact patch which should never be varied by distortion thru the sidewall. With the right camber setup, the idea of cornering becomes a simple mathematic/chemical equation of how much stress you can put the tyre under before it will let go. You must eradicate sidewall flex to make this equation work properly.

I'm a tyre guy! :thumbsup:
Always Gunna



Offline mondi

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The whole concept of a racing tyre is to get rid of the "side ways flex"................there is almost none in an R-spec tyre and you would be hard pressed to register any in a slick tyre. One of the things that destroys a road tyre, even a mega road tyre from one of our supercars, is the side wall flexes too much under the stress loads that are in evidence on the circuit.

The concept is that the tyre uses rubber compounds to generate mechanical grip and super stiff sidewalls to enable the rubber to generate it's "stickiness" on the contact patch which should never be varied by distortion thru the sidewall. With the right camber setup, the idea of cornering becomes a simple mathematic/chemical equation of how much stress you can put the tyre under before it will let go. You must eradicate sidewall flex to make this equation work properly.

I'm a tyre guy! :thumbsup:

Cool, thanks for the lesson in tyre theory.  :)

What I did mean is that as far as I can see these things would be TOO stiff. Am I correct in saying this?

What are your thoughts on these????



Offline Aircon

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The whole concept of a racing tyre is to get rid of the "side ways flex"................there is almost none in an R-spec tyre and you would be hard pressed to register any in a slick tyre. One of the things that destroys a road tyre, even a mega road tyre from one of our supercars, is the side wall flexes too much under the stress loads that are in evidence on the circuit.

The concept is that the tyre uses rubber compounds to generate mechanical grip and super stiff sidewalls to enable the rubber to generate it's "stickiness" on the contact patch which should never be varied by distortion thru the sidewall. With the right camber setup, the idea of cornering becomes a simple mathematic/chemical equation of how much stress you can put the tyre under before it will let go. You must eradicate sidewall flex to make this equation work properly.

I'm a tyre guy! :thumbsup:

seen how much flex an F1 tyre gets? i'm sure it's not there by mistake.

I love my car. Buy your own



Offline 993tits

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seen how much flex an F1 tyre gets? i'm sure it's not there by mistake.

You will be calling me Phil any moment now.........you're right in suggesting that anything an F1 tyre does is not by accident. The technology that goes into constructing an F1 tyre is just like the rest of the car........in another league.

I guess the issue is do we use an extreme situation like F1 to try to explain every single thing that happens on road/track cars? My brief lecture was tyre 101......not the advanced version. If you look at the vast amount of chasis changes that have occured over the years with F1, lower, higher, skirts, ground effects........all these things have made huge compromises in other areas that we would consider "normal" in non-F1 cars. Some have resulted in no suspension movement, some in more suspension movement, some have resulted in suspension materials being more elasticised so that they have minimum travel in the traditional moving components but the whole sub assembly can absorb shock.

Nearly every one of these has had a dramatic effect on tyre construction and how much of the load carrying and suspension activities have been forced on the tyres. This has also had an effect on how much profile the tyre has carried and this in turn has an effect on the ability of the tyre to flex in the side wall.

Anyway, you're being pedantic as you know damn well that a slick or R spec fitted to your 355 works better than a road tyre on the track because it has way stiffer side walls and a much stickier compound.......so, bite your arse!   
Always Gunna



Offline 993tits

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Cool, thanks for the lesson in tyre theory.  :)

What I did mean is that as far as I can see these things would be TOO stiff. Am I correct in saying this?

What are your thoughts on these????

OK...my concerns of this type of construction in a racing style wheel/tyre combination is not based on wether or not they can get the thing to flex or grip, but in the bonding of the rubberised components to the metal components. I'll give you an example:

My specialty is giant off the road tyres for mining trucks. Like the passenger car market, this sector has gone from bias ply tyres to radial construction. One of the factors that confronts tyres of 4 mtrs diameter and with a load carrying capability of 50 - 80 tonnes per tyre is delamination or heat separation. This can happen in both bias and radial tyres but it happens differently. The ideal is that the tyre heats up to 100 deg C and stays there but if it goes to 115 deg C and above, the rubber reverts and moves away from the steel or cord belts that it has ben bonded to. The steel belts in a radial tyre will also hold some of this heat and this keeps the rubber away from it until it cools in a different location and now you have the beginnings of heat separation. With an old style bias tyre, the bonding or vulcanisation is more efficient and the rubber does not move away from the bias belts as they tend to not hold more heat than the rubber surrounding them. If the bias tyre can be cooled quickly enough and stood down for a period, the heat separation may not occur to a failure situation.

So my point is that the closer chemically a material is to rubber, the less it likes to share it's space with metals. Metals are effected by ambient temps and extreme temps generated by, for arguments sake, drive components way too much for the rubber to be wanting to stay bonded to it. So the answer is to make the wheel component and the tyre component out of the same or very similar materials so you dont get rejection. This, if I remember correctly, was the benefit of the Michelin Tweel. The Tweels were made from a plasticised material of some sort??

Pheeeew! I love it when I talk like that!
Always Gunna



Offline mondi

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Pheeeew! I love it when I talk like that!

Well, I got Wood!!!   :D

I did wonder about how they got the Rubber tread to stick to the actual wheel(which looks plastic) and then to the hub which looks metal.
We have some amazing adhesives in the automotive industry now so I guess just about anything is possible.

I stopped being impressed when I saw a near new Volvo "glued" back together in the panel shop. The welder was not even turned on once.
After that I just thought I had seen everything!!!



Offline Aircon

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You will be calling me Phil any moment now...

i don't know you well enough to be so insulting.

Anyway, you're being pedantic as you know damn well that a slick or R spec fitted to your 355 works better than a road tyre on the track because it has way stiffer side walls and a much stickier compound.......so, bite your arse!   

yes i am....yes i do, and i would if i could.

I love my car. Buy your own



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