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Reinventing the Wheel
bob zee sent in this link about reinventing the wheel, err, tweel, err, whatever. Wheels are an interesting challenge in engineering design: they need to be hard to be durable, soft for a smooth ride, grippy to grab the road, but smooth to reduce rolling resistance, flexible to absorb shocks, yet stiff to reduce heat build-up, and so on. Rubber tires are a relatively recent invention.
Out of all the things to reinvent... the wheel?
I'm still waiting on that new mousetrap! That Rube-Goldberg device of a game just isn't cutting it.
Great. Back to the basics. What's next - the incline plane?
I wonder if other states maintain such restrictions?
Sigs cause cancer.
I agree. In spite of the obvious problems, tt does look promising.
On second thought, what if debris gets caught in the polyurethane spokes?
"Engineers at Michelin's American technology center here envision a future in which vehicles would ride on what they call the Tweel, a combined tire and wheel that could never go flat because it contains no air"
Please let them bring these out for motorbikes, thats one of those things we bikers dream about.. a tyre that never goes pop when your doing 100mph down the autobarnes.
moo
"Please let them bring these out for motorbikes, thats one of those things we bikers dream about.. a tyre that never goes pop when your doing 100mph down the autobarnes."
If you're doing a 100MPH down the Autobahn? Tires going 'pop' are going to be the least of your worries. Of course 'pop' could simply be Darwin calling another biker home.
When was the last time anyone of you had a flat tire?
Last week, you insensitive clod.So they improved it in two ways: It won't go flat. and you get more traction (due to stiffer side stability, which you can get in a narrow profile tire anyways)
But the negatives:
1) It Weighs More - and that weight has a huge impact because rolling mass is much more difficult to move
2) More Friction - Again, a drop in efficency due to difficult in rolling the wheel
3) More Expensive - No longer a need for "expensive" tire pressure monitoring systems (which probably aren't all that expensive, although they are sometimes troublesome) and you don't have to replace your tires as often, but if the tweels cost 3x as much, there is no saving here
4) Noise - No one likes loud tires.
Now I doubt they can get the weight down to a point that is ever lower than that of a rubber air filled tire (air is... well very light) but I could see a weight improvement, and the friction improvement both helping with research and design. And the cost of the tires will always probably remain higher, so this looks like long term technology to me.
I think this (http://marsrovers.jpl.nasa.gov/spotlight/wheels-i mage02.html ) is an example of government research going to a consumer product....
Think large....
No doubt this article submission will get bashed for not being about star wars; but this is a fairly interesting article, if you take the time to read it. I was particularly interested in the fact that this "tire" improves cornering while maintaining a smooth ride. No doubt all the NASCAR fans out there will be happy. While I am sure this is a long way off, it looks promising.
I tried for 5 years to come up with a clever sig...only to realize that I am not clever.
Rubber tires are already used in asphalt for improved roads, so the rubber tire landfill issue is becoming non existant.
most recently, a few weeks ago when i was in cairo and the taxi driver hit a pothole, bending both rims on the passenger side, leaving the tires flat.
before that, about 2 years ago when i hit a roofing nail, causing a slow leak (woke up the next morning, tire was flat)
then we could also count biking...in which case i've had more than i want to count, and a bike tire that can't go flat would be awfully nice...nothing sucks more than having to stop and patch a tire in the middle of a bike ride...plus having to carry all the tools needed to do the job.
this idea has merits, contrary to what your post seems to imply.
There is also the argument that because you only need to replace the tread, fewer resources are consumed in the replacement process (an environmental boon on the other end of the product's life).
Gee, do you think maybe these engineers aren't total idiots?
I mean, seriously.
Not to be mean. It's a thought. I'm sure it took them all of 12 seconds to decide not to expose a bunch of radial fins on the side of the tire. Maybe another 4 to decide not to make the tire out of chalk, too. I bet they spent another 9 rejecting granite sidewalls as an option.
-Lep
I am allowed to criticize you: you are not allowed to criticize me. Sorry, that's just how things are.
Are you an idiot? No, seriously. That was a CUTOUT so you could see what it looks like inside! Do you think any engineer would be so stupid to design a tire like that? If it didn't have a cutout, someone as ignorant as you would proclaim that it looks no different than a typical radial!
A blog like any other.
For what its worth, I have a master's degree in Mechanical Engineering and am, in fact, an idiot. So its not impossible...
Custom, hands-free Linux installs. Instalinux
if the tweels cost 3x as much, there is no saving here
If they last 3x as long (as the article suggests they might) then it balances out, and there is at least a possibility of savings of time from not having to change the tires as often, not to mention the lower volume of scrap material.
You can never go home again... but I guess you can shop there.
Um, no. Lighter wheels result in smoother ride because the suspension is able to move them up and down quickly over rough surfaces. Heavier wheels don't move as quickly, and movement from uneven surfaces winds up being transmitted to the rest of the car. This is why vehicles with big wheels (like trucks) tend to have a poorer ride quality than cars.
Also, lighter wheels can be pushed back down after bouncing over a bump more quickly than a heavy wheel, which means better traction.
The key here is the decoupling of the spring rate of the tire from the sidewall stiffness. That is HUGE and will give them all kinds of ability to dial in performance, ride, and other characteristics.
But there is a definite shortage of info in this article.
The statement '2-3x longer tread life than a radial' could be great, or it could be meaningless. Tread life is largely a function of tread compound, and a trade-off against grip level. They can make an extremely grippy tread that will only last for a few laps to qualify for a race, or a hard tread that will last 100K miles, but not both. Are they are actully projecting an ability to control the contact patch of this new wheel/tire so well that it wears less with the same compound, or are they merely planning to build it with a hard compound?
Another issue is the weight. Extra weight here is in the worst possible place for the car's performance -- rotating, unsprung, and far from the car's rotational center of mass. This wheel/tire looks heavier with the ribs under the tread. However, it could actually be lighter with polyethelene spokes, and lighter sidewalls that only have to keep out dirt, not react the loads. (Of course, I'm not sure how far I'd want to push the side loads on those poly spokes, but that's another story...). I'd have to conclude right now that it is heavier, or they'd promote that benefit too.
I think they're on to something interesting here. Is there any other info around on these issues?
In the not too far future, cars will basically be designed like a cheap printer. When it breaks you will just throw it away and buy a new one.
The cars will be made out of mostly composites and plastics. This means that you will need to hire a specialist to do even the most minor repairs.
Every aspect of the car will be electronically controlled and monitored and you will need special equipment to even begin troubleshooting the numerous electrical problems that will crop up. There will be so many electronic controls that if there is an electrical problem; basically it's non-repairable.
Many car manufacturers are planning on sealing up the engine compartment and the engine itself. New super-lubricants are developed to last the 'life' of the car. (Previously on Slashdot)
The Tweel fits into the same category. The major gripes of it are that it incorporates the tire, rim, and hub all into 1 package. When something like this goes mainstream, forget about custom wheels. Right now there is a big market and all sorts of different tires available for the consumer. If there is a specialized product like the tweel, then it would basically be a monopoly.
The pneumatic tire has been around for 100 years and it has been constantly improved for the entire time. There is very little growing room for the tweel.
Current models are heavier than a standard wheel. This increases the rolling mass which makes it harder to accelerate and stop. They will eventually get old and with all the stress they are likely to fail and collapse. Plastics become brittle with age and with all the stress they would be taking will cause them to fail and cause a nasty accident.
The new marketing strategy of the throw-a-way car will claim it's safer and more fuel efficient because of the weight savings. It will eventually lead to having to recycle your car about every 10 years.