| Author | Message | ||
     Oldog |
You will enjoy this  http://www.foxnews.com/leisure/2013/05/08/revoluti onary-new-design-takes-wheel-for-loop/?intcmp=feat ures | ||
| Hootowl |
Interesting. Passing along to all my pedalphile friends. (I learned a new word today from an online article -I'll never be able to find it again to reference but - the author states that it's a new word he's kicking around, and to let him know if you see any problems with it  ) | ||
| 86129squids |
Neat idea- I'm kinda surprised nobody had thought of this sooner though... | ||
| Stirz007 |
Cool idea - BUT - standard bicycle brakes won't work...gotta go with the drum shown or a disk set-up. It'll be interesting to see where this goes. | ||
| Sifo |
What the world needs is a more complicated suspension system that has no dampers. Pass. I can probably see half a dozen other reasons why this will fail miserably. | ||
| Natexlh1000 |
Here is another odd thing that came to my mind.... If you compress the wheel, the radius of the wheel between the contact patch is decreased. The radius of the brake remains constant. The braking effect increases with loading! What happens when you decelerate? That's right, weight transfer forward. Loop out with the front brake due to increasing braking effect? Just the same, I am intrigued. I would love to try a bike with these on it. | ||
| Sifo |
So I said half a dozen reasons it will fail. We already have complexity, won't work with normal rim brakes, changing radius while braking and being called a pedalphile. Let's add... 1) Excessive rotating mass. 2) Braking forces will change rake and trail. 3) Proprietary rim limits choices. 4) No ability to true the wheel 5) A normal bike wheel get strength from spokes under tension. This system will require a much stronger (heavier) rim to achieve the same strength. 6) Huge aerodynamic drag compared to conventional wheels. I'm sure there's more, but I only promised 6.  (Message edited by SIFO on May 08, 2013) | ||
| Stirz007 |
If there's sufficient rim stiffness, radius changes shouldn't be significant, and as far a change in rake/trail/dive, I don't see it being any different than MTB front suspension. Agree on mass, drag, truing issues. Sometimes you throw out crazy ideas to see if the dog will hunt or not....for now I'd stick with spokers, but that's just me. | ||
| Sifo |
It's not about rim stiffness. The effective radius changes as the wheel works as a suspension. Any force sufficient to deflect the springs will change the radius. That's why I say that braking force will also change the radius in a way that will reduce rake and trail in addition to the normal changes you get from simply compressing a suspension. | ||
| Sifo |
It also looks like it will be very expensive, but they gave no details on that. | ||
| Ratbuell |
Um...price was in the article. Set of two, $760. Mass? I'd guess, since it's composites, it won't have any more mass than a bundle of spokes. Cool idea. And being tested for over 10,000 miles...I'm willing to bet if any of the braking or handling issues had reared up, they'd have been found, analyzed, and fixed. | ||
| Midknyte |
>Neat idea- I'm kinda surprised nobody had thought of this sooner though... Did, kinda http://www.gizmag.com/reinventing-the-wheel--the-a irless-tire/10398/ http://www.youtube.com/watch?v=4jYcX_D09ig | ||
| Cityxslicker |
chrome it put some skullz on it add it to the P & A catalogue..... Pity that OCC is no longer around - you know they would put it on one their things | ||
| Patches |
Too much energy wasted on each power stroke. Its like running on a flat tire. Watch the video. http://www.bing.com/videos/search?q=loopwheels&vie w=detail&mid=040B4173E75B48C7A9FB040B4173E75B48C7A 9FB&first=0&FORM=NVPFVR | ||
| Sifo |
Um...price was in the article. Set of two, $760. Thanks, I missed the price. So they are priced at the very high range of hand built spoke wheels. Most people wont pay that much for a bike. I notice that the fork is also proprietary to keep the hub from spinning when brakes are applied. A more standard disk hub would fix that though. Same issue for the frame at the rear wheel. I don't see the folks who are willing to spend that much on a wheel set going for this wheel that creates more problems that it solves. It's a true Rube Goldberg device. One more issue, under hard braking, it's going to wind up like a spring. It is a spring. At the limits of traction you are going to experience uncontrolled chatter as the tire starts skipping across the ground. Good video of it that Patches posted. The guy talks about dampening. That has to do with water. The term is damping. That's the roll of a shock absorber. This set up has no shock absorber at all. You can actually see how this works in one of his test rigs where the wheel repeatedly bounces off the ground. This is exactly what you do not want in your suspension. Putting that on the rear wheel will tend to put you right over the bars. Suspensions NEED damping control. I would also be concerned about the torsional stiffness from side to side. I could see addressing this if you can manage to design composite springs that will not twist, but I have my doubts about this. This is a product that will not make it in the bicycle market place. I could see it functionally in the "toy bike" market. Think the toddlers bike sold at Wally World. The price will prevent that though. FAIL! | ||
| Pikeben08 |
Didn't watch the video but it seems like the spring force would vary somewhat as you are changing the angle that the axle is exerting force on the springs, especially when transferring from one to the other. | ||
| Aesquire |
Damping is built in to the Composite material, it's not like Metal springs. Enough damping to deal with Sifo's complaints? Perhaps. I ride a bike with polymer "shocks" in Seat tube & handlebar stem. It works fine. ( even though you DO get a radius change on the crank/butt distance, it's workable, and light ) As designed, it's pretty nifty. I like they way they spiral the springs to give it some lateral stiffness... but notice the wheel on the "rolling road" test machine is out of true, and wonder if it's possible to true it back? That same spring config makes for one of Sifo's complaints,that it's an Aero drag loser. ( but no worse than some kiddie bike plastic wheels ) The configuration they have is neat, but the overall concept is old. NASA developed suspension-in-wheel for the Lunar Rover Program, and the idea was not new then. ( final version of the Rover Wheel was all metal, with wire mesh "tires". With a 400 degree day/night temperature range, inflatable rubber isn't the answer ) http://en.wikipedia.org/wiki/File:Lunar_Roving_Veh icle_wheel_close-up.JPG http://en.wikipedia.org/wiki/Lunar_Roving_Vehicle# Wheels_and_power Others..... http://www.gizmag.com/michelin-tweel-for-lunar-rov er-vehicle/10997/ | ||
| Kenm123t |
The Lunar rover motors and drive electronics were made In West Palm Beach Fl The plant still makes F16 actuators and drive transistors | ||
| Sifo |
Damping is built in to the Composite material, it's not like Metal springs. Enough damping to deal with Sifo's complaints? Perhaps. Well I have my doubts. I'm not familiar with composite springs like that having damping built in (they did mention it was modeled from modern bows with have no damping). Assuming that they provided damping though, there's a real problem. When you hit a bump and the damping slow the return, the wheel is spinning at the same time. One part of the wheel has to rebound while another has to compress as the wheel rolls over a bump. It's just not going to work right. In fact given that any spring will have a certain amount of sag built in at its loaded ride height, just rolling along smoothly will have the spring constantly compressing and rebounding. Building damping into a wheel like this is taking energy required to move the wheel forward. This is a killer of a bicycle where you have very little horse power. With or without damping built into this system, it has created problems that don't exist with what is commonly available. As for the comment made earlier about the aerodynamics being about the same as some kiddie bike wheels, I think you would find that these are actually worse. Even if they were equal, you would never pay this price for kiddie bike wheels. | ||
| Aesquire |
No argument, and I could be very wrong on the damping. I also wonder about torsional stiffness. How much windup do you get with each power stroke. | ||
| Ourdee |
Should use roller brakes. | ||
| Saxon59 |
Way back when Triumph Motorcycles had a rear suspension system that used springs and ball bearings in the wheel hub on a hard tail frame,the axel would move up and down in the hub,however,the wheel would also move side to side,not good.This is similar to the old Indian Motocycle rear suspension.Of course these were on heavy motorcycles,but,I can see the same problems with this system. . | ||
| Blake |
Any significant damping built into the spring/wheel assy would kill rolling efficiency. This appears to be a solution looking for a problem. Still a neat idea though. Maybe some very efficient springs along with some dyna beads for the damping. | ||
| Natexlh1000 |
LOL @ dyna beads. They should just make the while bike out of dynabeads so every part will be perfectly balanced. | ||
| Aesquire |
Don't forget the magnet for the fuel tank..... Oh, yeah, a bicycle...... I mean..... The seat. | ||
| Blake |
LOL. But seriously, the one thing those beads can do is damping. I think there's still just too much energy loss in the continuous flexure of the springs though. Not quite as bad as a flat tire, but one low on pressure for sure. | ||
| Sifo |
I'm not convinced there's much energy loss in the flexing of the springs. They said they are based on bow technology. Bows are quite efficient at releasing the energy stored in them. As they roll, they will certainly be absorbing energy as the spring is flexed, but on the other side of the axle you will have a spring releasing it's energy back into the system. The big problem is that this is like riding a pogo stick. Some early bicycle suspensions lacked any real damping. They proved terrible to ride. As soon as you introduce damping to this sort of suspension, you will find all that energy consumed by damping will also impede your forward progress. It will also have the same damping on rebound and compression. That makes for a lousy suspension. The most basic of non-adjustable suspensions still have different valving for compression and rebound. I'm not at all clear what "problem" this solution solves, but I see a whole slew of problems that it creates. EDIT: I'm still waiting to hear of someone doing an actual test of dynabeads where a wheel is purposely weighted to be out of balance so you can feel it at a known speed then adding the beads to see if it corrects the balance. Simply adding them to a fairly well balanced wheel only demonstrates that they don't make the balance worse. (Message edited by SIFO on May 31, 2013) | ||
| Natexlh1000 |
The scientific dynabead test is tempting to me since I'm due for a tire change anyways. What is the density of airsoft pellets vs magic dynabeads? Any imbalance would be more noticeable in the front since the rim+tire+brake is lighter. | ||
| Sifo |
I would probably do the test before the tire change. Your wheels should be balanced fairly well now. Just add wheel weights until you can tell it's out of balance at, say 55 mph. Then add the beads. If they work, you should be able to go 55+ without noticing the out of balance situation. Then you can decide if you want to dump them or put them in the new tire. To be fair, substituting anything for the actual magic beads does kind of invalidate the test. | ||
| Blake |
They don't a lance; they only dampen. The best spring will not be 100% efficient. Heat happens. |
