A bicycle can cut friction in half, called "Half Bicycle"
- Thread starter iwico
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dgregory57 said:People have been able to ride wheelies for years, and in fact, isn't there a racer known for pulling a wheelie once in a while for fun? Someone who raced professionally some time in the past several years, and may still race... It seems that I have seen a video of someone doing it at the finish of a pro race.
So, what exactly are you adding to what someone can do by riding a wheelie?
And I agree that a wheelie bar does nothing but add weight... even if you add a fancy name to it. They had them for stingray type bikes in the 70's.
And if riding a wheelie is most efficient, don't you think that the professionals would be doing it? After all, they have dynomometers (sp) and wind tunnels to test all of the possibilities for gaining efficiency.
Hi
After see the wheelie picture, you can see the front wheel is left from the ground about half meter. And there is no guard wheel C at back, if the cyclist turn bicycle back little bit too much, the bicycle will turn over. It need good skills and unsafe.
Purpose of this "Half bicycle" is to make the "wheelie" much safe and easy.
Regards
Mr Q Gang
Akadat said:All the weight on one wheel, or half the weight on each of two wheels? I think the difference in efficiency will be the viscosity of grease in one bearing, which will be less than if you had a drink of water before the ride or not! The weight of the third wheel in the picture will cancel out any gain in efficiency even if you manage to ride on one wheel.
If races are won using your system then everybody will believe it.
Talk little bit more about the friction between wheels and the ground.
The friction between wheels and the ground, depending on 2 facts:
1. weight on the bicycle.
2. the area of tyre touch the ground.
If weight is same, then smaller area, less friction.
I sampled one before, about little unaired tube will increas friction lot. Every cyclist will understand this.
I have another sample: On race bicycle, the wheels is designed very narrow, Why? because it need to reduce area of the tyres touch the ground, to reduce friction. If as someone said, the friction only depending on weight, then why race bicycle uses narrow tyres?
This "Half Bicycle" not only reduce the area, it just make a wheel A left from the ground, whole area is disappeared. By this way it can cut friction in half.
Regards
Mr Q Gang
Dude, repeating the same bad physics over and over again wont make it true. Friction between the road and the wheel is why the bike propels forward. Rubber deforms and wastes some of the energy and this is called rolling resistance. No one here is disputing reducing surface area in contact with the ground is a good thing. It is simply not the most significant factor.
scuppy said:
Reducing the size of the contact patch is in almost every case, not a good thing, especially if you want to do things like go around corners, make emergency stops, and the like. The only real way to reduce contact patch is by over inflating.
I don't see the point of this "invention." It has absolutely no benefits that are apparent. The moments that such a contraption would generate would make it at least very unstable. Riding it with one wheel off the ground will increase the aero cross section causing it to require more power to overcome drag than a traditional bicycle. Riding it on two wheels will be just like riding an overweight bike, so in that case it won't be as good as a regular bike.
As I said earlier, the ability to avoid hazards and to make quick avoidance maneuvers will be non-existent. The moveable weight will destabilize the bike every time the bike hits a bump. If on one wheel at the time, the risk of a crash goes way up. I also think it's likely that a quick aggressive yank on the brakes, as in a panic stop, will overload the front wheel with excessive weight transfer from your moving weight. In two wheel mode that'll either mean doing an endo or if the pavement is slick, dirty, or etc, tucking the front wheel. Either way, flesh meets pavement. Then there's that bump or pothole that causes movement in the moveable weight when on one wheel which could destabilize the bike such that the bike rotates backward. Crash.
I seriously doubt there is any market for this thing, unless you count circus clowns.
It's apparent that not a single analysis has been done of this "design." You'll need a good barrister to protect from the inevitable liability claims.
sideshow_bob said:
McEwan, one handed and in trainers. Don't try that at home kids.
Hi McEwan
Could you tell everone here:
In wheelie position, do you feel friction between wheel and the ground is reduced? In other words, do you feel lighter than 2 wheels on the ground?
Regards
Mr Q Gang
You know, I really wouldn't count on Robbie reading this thread, diverting as it is.iwico said:
iwico said:
It's absolutely clear that you do not understand:
- friction
- friction's role in the function of tires
- contact patch
- the magnitude of rolling resistance losses compared to other power losses in the bike/rider system
- equilibrium and unstable equilibrium
- moments and how moments couple with forces
- aero drag and its magnitude compared to other power losses
As for McEwen and wheelies, he, like other humans, has a system that can respond to moments very quickly. You will fail to build a mechanical system that responds as quickly or even quickly enough to respond to said changes.
Clearly, you have no idea what you're talking about. You remind me of the guy in Youngstown, Ohio that claimed he had built a machine that had zero energy losses, one that proved invalid the Second Law of Thermodynamics. Of course his machine was only a 10% mechanical efficiency, but he said he was still "working out the bugs."
Oh, there is this tiny little nugget: When you transfer all the load on two tires to a single tire, guess what happens? That's right: hysteretic losses--rolling resistance--will at least double. In reality, it will more than double since the rear tire will experience much greater flex. Of course, a person could erroneously try to circumvent this by over inflating the tire and reducing, as your prone to say, the contact patch.. Guess what happens when you reduce the contact patch below it's nominal area?
The extra concentration required to maintain equilibrium would not be insignificant. The brain is a glucose hog.
Plus, it would be much harder in a tuck because your torso would not be balancing over the rear wheel, as with an upright unicycle rider.
Aerodynamic drag is one reason not to have a tricycle. This contraption has three wheels, just like a tricycle. I wonder what the rolling resistance of a high performance trike is, but I bet it's not significantly higher than a road bike when all wheels are holding up the rider's weight.
Plus, it would be much harder in a tuck because your torso would not be balancing over the rear wheel, as with an upright unicycle rider.
Aerodynamic drag is one reason not to have a tricycle. This contraption has three wheels, just like a tricycle. I wonder what the rolling resistance of a high performance trike is, but I bet it's not significantly higher than a road bike when all wheels are holding up the rider's weight.
I'm working on a revolutionary design for cars, wherein to improve gas mileage, the car will raise up and balance on the left rear tire. Also, the left rear tire will automatically grow or shrink to account for changes in driving conditions.
I'm also going to be marketing polished chrome, as well as gold plated, spinner hubs for monster trucks. This will certainly reinvigorate monster truck racing series and will no doubt increase truck sales in the US, Canada, and the Turks and Caicos.
I'm taking advanced orders now.
I'm also going to be marketing polished chrome, as well as gold plated, spinner hubs for monster trucks. This will certainly reinvigorate monster truck racing series and will no doubt increase truck sales in the US, Canada, and the Turks and Caicos.
I'm taking advanced orders now.
A guy rode the metric 100km route on a unicycle at our fall century this year. A buddy who was riding with him told me he was going 12 mph on flats, uphill and downhills. Sounds like an impossible feat to me, but apparently the rider is a tough endurance runner who just likes something different.garage sale GT said:
The high-performance trike I'm familar with has two front wheels with the rider sitting very low in between them. It's very fast downhill due to the minimal frontal area, but stability in hard cornering is a problem since it doesn't lean into a turn. Also, with seperate brakes on the left and right wheels, high-speed braking on descents is a real challenge due to the need to keep straight as the CG shifts forward.
I saw a friend crash his into a guardrail when he lost control on a twisty descent. He was behind us on the climb, but as we started down the descent, he smoked by us and passed at ~ 50 mph going into the second corner. A touch of the brakes was all it took to flip the trike and send him into the guardrail on the outside of the turn.
McEwen said on local radio that the fans always want the wheelie, but, sometimes, at the end of long, hard stages of the Tour, he's so stuffed he thinks he might fall off if he does one, but he usually does them anyway, coz the people were goading him. See, maybe he's no so bad after all
531Aussie said:McEwen said on local radio that the fans always want the wheelie, but, sometimes, at the end of long, hard stages of the Tour, he's so stuffed he thinks he might fall off if he does one, but he usually does them anyway, coz the people were goading him. See, maybe he's no so bad after all
Hi
Up to now, no a single cyclist (who can do "Wheelie") in here to tell us what happened when on Wheelie.
I like someone who can do the wheelie, to tell everyone here:
1. Do you feel the wheelie reduce friciton?
2. Is it easy to get the gravity point on the back wheel.
3. On wheelie, can you change direction?
On McEwen's wheelie picture, we can see some points:
1. He only need one hand on hand-bar, that means it is not very difficult to do it.
2. The road is not smooth, he can do wheelie on it. Not like someone said here if road surface is not smooth, wheelie will fall down.
Regards
Mr Q Gang
iwico said:
Yo. Go back to school. You have no clue what you're talking about.
Wheelies? Yup, I can and have done 'em. There not faster. Nope. No matter what your fantasies are, wheelies are not faster. Never have been and never will.
You will not that McEwen doesn't wheelie in races. Now why do you think that is?
Do you have any education? It doesn't appear so from your beliefs and statements.
Here's a website that should help you out: http://insti.physics.sunysb.edu/~siegel/quack.html
I used to ride wheelies a lot... so I do know what I am talking about...iwico said:
However, let's look at a professional who rides for speed and efficiency, where I only rode them for fun. Yes, you can make turns while doing a wheelie, as far as friction, I could never tell, because you do them for fun, definitely not efficiency.
However, I think it is safe to say that the efficiency of a wheelie is disproven by the ease with which Mr McEwen does them. Since he can ride wheelies, and yet he still chooses to ride the race on two wheels, I think it shows that he feels it is the more efficient way to ride. If it was more efficient to ride on one wheel, he would do it.
My earlier post did show the picture for me initially, but it disappeared, but also your "safety wheel" is nothing new... do a google search for "bicycle wheelie bar" and you will see that they have been around since the 1960's.
Let's see if this one sticks...
I didn't say they were a good idea, just pointing out that they aren't a new idea.alienator said:
I remember riding a bike with one once... a friend must have had one, but I don't recall who. As I recall it actually was harder to ride it on the wheelie bar than to just ride a wheelie without it. Of course, maybe it was because I wasn't used to it.
I thought the guy on that bike isn't the usual kid you would expect to see in an ad for that sort of product either... Maybe more of the before picture in a before & after ad of some sort. Of course, thinking back to the time frame, maybe he was the younger version of the outlaw biker of the 60's... I'm trying to remember what the neighbor bikers looked like when I first moved into the neighborhood in the mid 60's versus when I joined the service in the mid 70's. It was a time of significant changes in look for a lot of people.
iwico said:
1. Just because something is easy to do does not mean it is efficient. You will not find someone riding a wheelie or a unicycle at 20+ MPH for hours on end. The extra effort required to stay upright will fatigue you far faster than the effort required to stay upright on a regular bike. Build your contraption and then try to ride a century on it... Watch how many people pass you. Then tell me yours is more efficient.
2. Easy to get centered on back wheel? Sure, but try maintaining it for hours on end. It just will not be easy to maintain.
Go back to the drawing boards...
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