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.
I wonder if other states maintain such restrictions?
Sigs cause cancer.
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.
Rubber tires are already used in asphalt for improved roads, so the rubber tire landfill issue is becoming non existant.
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).
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.
There are also power-generation facilities that burn discarded tires to generate electricity.
I have something in common with Stephen Hawking...
Wrong wrong wrong. At least in the province of Alberta where I live. In fact the report I just read but the Tire Recycling Manufacturers Association said that they were worried that there wouldn't be ENOUGH used tires to fill the increasing demand for different scrap tire rubber products.
Now these uses are far more than rubberized asphalt, but that is only one example of the many products you can create with this.
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?
When President Eisenhower went to Kansas to announce the interstate highway system, he announced it as "the National Defense Highway System." In 1956 President Eisenhower signed legislation establishing the National System of Interstate and Defense Highways (about 41,000 miles of roads).
Now, what your typical razorback trooper's going to say might have as much to do the size of your gun as it does with how much tarmac you've chewed up.