Slashdot Mirror
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.
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.
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.
You obviously never drove any German Autobahn, I'm sure. 100mph ~ 160kph and that's a normal vehicle speed over here. 130kph is officially "suggested" speed, but especially bike riders go lengths and lengths beyond that. 250kph ~ 155 mph is upper limit for most German motorbikers.
Trucks and heavy vehicles can go 80kph/50mph, buses 100kph/62mph and everything else is unlimited by law.
Compact cars, 3-doors etc. usually drive between 80kph (old and rugged cars/drivers) and 130kph with a few exceptions, notably Volkswagen "Lupo" and "Golf" in the "suicide engine" version with 120 or more HP, they are driven by lunatics 200kph or more no matter if the road is dry or below solid ice. But they are few and far between and you sure know why.
Middle-class goes between 140 and 200kph, that range usually covers the bulk of cars. High powered suicide versions exist in this class, too, with 200 or more HP. And people who own them drive accordingly, tendency stable - more airbags 'n stuff I suppose.
Cars beyond 200kph are less than 10%, usually the upper BMW, Mercedes Benz and Volkswagen models. They announce themselves from half a kilometre away with full headbeam and constant left turn indicator. If any driver is in front of them, they will brake at the last moment possible, if ever. Most other drivers cave in long before and leave the fastest inner lane rather quick if they see them approaching.
Tire popping is seldom cause for accidents, most of the time it's trucks or other vehicles breaking out of 80kph formation on 1st going into 2nd lane overtaking some while forcing a "regular" car going 180kph or less out from 2nd to 3rd fastest lane. Where they collide with a suicide compact or fast upper class car from behind.
I don't know that many Autobahn routes here in Germany, but I'd wager 30-40% of all routes are unlimited and 3-lane. The rest is 2-lane and limited to 120kph/75mph or 100kph, as the road condition permits. Autobahns passing larger cities are often limited for "lower noise level", near poorer cities for "speed control fills city coffers"-reason.
It is not uncommon to have limits on a road to exist for various reasons, wind, noise, whatever, but road condition permits MUCH higher speeds. Everyone drives according to road condition then, bearing the risk of being "flashed" by police with radar speed cameras. Poorer municipalities are actually notorious for this and you cannot drive more than 200kms without meeting one of these cameras if you're unlucky.
In cities, there are even more cameras. Can't drive longer than 30 minutes without seeing one in any city. It is even possible to have the German police temporarily limit a normally unlimited stretch of 3-lane Autobahn to 80kph or less and then lurking for and cashing in on "speeders" at the end of that temp limit zone. Shameless entrapment.
Fines for speeding ~25 euros for less than 10km over, 50 euros for less than 20kms over and 100 or 200 euros for everything beyong, leading quickly to 2000 or losing license for more than 40 above.
Germany has the most eased road laws in Europe, so nobody obeys the speed limit nowhere. In answer to that, speed limits are set much too low everywhere in hope the drivers will go their "usual 20kph" above and still keep on track. That way police and law enforcement can endlessly bilk drivers for their money while always having law on their side and public outrage silent. Nice trick, eh?
In Norway for example, 10kph over the limit are rather expensive: 200 eur, 600 for over 20kph. There, speed limits are set almost right, with around 5-10kph left above. Eastern Europe speed limits are equally hard for everyone carrying Euros in their pocket but speed limits are brutally true. Any limit posted is true to the letter if not a bit daring on a dry and sunny day.
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?