Naked Science Forum
Non Life Sciences => Technology => Topic started by: John Chapman on 02/03/2009 10:43:29
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I've received an email that is doing the rounds and is quite interesting and I apologise if you have already seen this. I'm not much of a car fanatic so I have posted this for all you petrolheads in Naked Scientist land.
This is an original approach to tyre design by Michelin in South Carolina, USA. See through tyres they rather hideously call 'Tweels'. They showed them off at the Philadelphia car show.
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Those are 'spoke' like connections to the inner part of the tyre from the outside tread 'wrap!'
The next picture shows how odd it they look in motion....
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These tyres are airless and are scheduled to be out on the market very soon. Just think of the impact on existing technology:
No more maintaining air pressure and fiddly air valves. No more blow outs. No more flats...
The bad news for the Police is that 'stinger' spike strips will not work on these.
What do you all think?
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Tweels - They were obviously named by a Yorkshireman.
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My initial wonder is their production. Considering how many billions of tyres there are in use, are these any more environmentally friendly in their manufacture?
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Yes, it would be interesting to know if they use more rubber than conventional tyres. Obviously they have no walls but there must be a lot of rubber in the 'spokes'.
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The design of the spokes would be interesting to understand. They cannot be as simple as they look because a conventional wheel spoke is not designed to work in compression and relies on a rigid outer wheel to translate forces into traction on a lot of spokes on the higher side of the wheel. These must be design to withstand a local compression as seen in the picture of the tyre hitting a kerb. It is hard to see how the force can be distributed very much and one would not expect that the bendy rubber spoke would resist local forces very progressively. I suppose the tyre itself must have a fair degree of rigidity to avoid impacts from kerbs etc. smashing the tyre into the metallic wheel rims. Interesting.
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My initial wonder is their production. Considering how many billions of tyres there are in use, are these any more environmentally friendly in their manufacture?
If they are less eco-friendly (complete product-life analysis) than what is already on the market they should not be used. Not only will it result in different tires, it may also result in huge infrastructure changes. Think about the equipment that is currently in use to install, repair, exchange, etc. regular tires. Now they would need additional equipment? Good for a growth-based economy, not good for efficient resource use.
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Good point, Karston. But they do look pretty cool, though.
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I wonder if these 'spokes' would loose their rigidity and/or spring in time and how they react under cornering, and breaking, at high speed.
What problems would a large stone, or similar, cause if it became lodged between the spokes? What further problems would it cause when released and flung out when the vehicle is travelling at say 100kph? I wonder if a wall might not be a good idea, but could that cause overheating of the spokes?
What off surface noise?
It will be interesting to see the road test reports on these.
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Where I live (Vermont), we experience snow for 6 months of the year. What happens if those voids fill up with snow or slush? What happens if I park my car in a 5cm deep puddle that freezes solid over night? Every April we have mud season. Ruts in the dirt roads filled with liquid mud. What effect would that have? Often I have vibration issues since snow/ice/mud accumulates unevenly on the wheel. This design seems to allow this to happen more easily.
Additionally, do you still have to be able to adjust the tire for vehicle weight? Do the spokes recover completely if I don't move the car for several months? Can they handle ABS systems?
It might be an interesting concept for an emergency tire if it weighs less than what is currently available. You would never have to worry about checking for air in that 5th tire.
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Good point, Karston (sic). But they do look pretty cool, though.
Yes, they do look interesting. Combine them with certain rims and it will look like your car has no wheels when you are at speed.
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I was just looking at a review of the Tweel, when I saw:
"Major revolutions in mobility may come along only once in a hundred years," said Terry Gettys.
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Check this site for a military version:
http://www.sciam.com/article.cfm?id=tires-that-dont-need-air
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I'm wondering how many deformation cicles could the spikes live before losing their perfect elasticity.
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Hi Dentstudent
Was that review online? Can you supply a link, mate?
Karston, that was interesting about the military version that can't be punctured with bullets or shrapnel. Here's a picture:
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Gary boys could have a field day!
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Sorry DB, but what are (or who is) Gary boys, and why would he have a field day? [:-\]
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Cool tires! [:)]
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I think this is a bit of attention grabbing styling. I'm sure the problems which I pointed out and Karsten noted
What happens if I park my car in a 5cm deep puddle that freezes solid over night? Every April we have mud season. Ruts in the dirt roads filled with liquid mud. What effect would that have?
if these tyres are to become a serious alternative to pneumatic tyres, they will have to have a wall.
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Hi Dentstudent
Was that review online? Can you supply a link, mate?
Hi John - sorry, I can't remember exactly which one it was that I was looking at, but here is another online one.
http://www.gizmag.com/go/3603/
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Sorry DB, but what are (or who is) Gary boys, and why would he have a field day? [:-\]
It's what we call younger people who usually drive flashed-up hot hatches and race round carparks late at night with music blaring.
Just found this in Urban Dictionary:
Much like a Barry boy, a Gary boy drives around in a car (usually some old model they bought second hand) with the music pumped up so loud that it shakes houses as they pass. Have often modified car's music system by stuffing speakers into the boot ect.
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That's what I like about this forum. Education, education, education.
Thank's DrB.