Reinventing the bicycle wheel

I'm having difficulty seeing how this would be of sufficient benefit without plug-in recharging.

It seems similar to having a Prius in which the traction battery is charged only by regenerative braking, with no other efficiency improvements over non-hybrids. While that does provide a nice increment of efficiency, is not enough to justify the cost, and in itself is not enough to be revolutionary.

 

The device will have to be *really* light to make the carrying cost worth the regen benefit.

 

I'd rather have an electric bike.

 

I always wondered if something similar could be accomplished on a bike by using a coiled spring of some type.

 

A coiled spring? Where would you put it? And how much would it weigh? I can't imagine it would get you very far at all.

Electric bikes are a good idea as far as they go, but they work best in an urban environment with mostly stop and go. As soon as you reach a hill bigger than the storage capacity, the system becomes dead weight and actually slows you down. Think of your body as the energy storage, and the bike and rider as a synergetic, computer-controlled hybrid.

 

Or you have to go with much larger battery capacity and good regenerative braking. I agree that with the current state of battery technology, they are actually a net loss for riding, but a really good electric booster can take the curse off of hills. This is especially true with recumbent bicycles, which are not very good for hill climbing.

Tom

 

Tim I applaud your outside the box thinking, no matter the practicality (I'm not commenting on practical matters). It's the 'outside' thinking which moves mankind forward. Even if in this example Tim's thoughts about springs prove to be unworkable, the next guy might think something like...hmmm capacitors can hold lots of power but can't slowly and practically release it. What if we take that capacitor, store energy until we need it then transfer it to a spring which CAN release power in a more controlled manner...You see folks, thinking people can build on each other's ideas whereas people who do nothing but follow blindly contribute nothing to the long term solutions society seeks for all our betterment.

 

It could reside in a closed "canister" on each hub. Upon braking the coil could be wound up. The idea is not to carry the rider very far. Most people are quite capable of pedaling on a flat or downhill. It is on the uphill when people get too pooped that they could kick in the spring boost to give them that extra push by releasing a lever of some type.

Anyway, I wouldn't use it - I ride regularly and consider myself able to climb pretty much any hill with my existing gearing. But for the casual rider this might be helpful. As for the weight - I can't say. Obviously this is an important consideration - the benefit would have to offset the weight. But I think such a system would weigh less than an electrical system with a lead batteries, no? Certainly it would cost less too.

 

As long as we're on the subject, does anyone have any specific comments on, or experience with, the new Trek electrics:

Trek Bikes | Bikes | Electric Bikes

As my wife said, this seems to defeat the whole purpose of getting a bike for most people, but I can see where it might make it easier or more likely to commute on one. They tout sweat free commutes and pulling trailers.

 

I don't recall ever being accused of not thinking outside the box before. Usually my ideas are impractical or too difficult and expensive to implement.

Bicycles are already so good that they're very difficult to improve upon. To paraphrase an old Scientific American quote, "A person on a bicycle is more efficient at turning energy into motion than any other machine or animal." Unfortunately, the refinement of the bicycle was held back for many decades by the UCI, which defined the design as a racing class for its own purposes. More recently, many innovations have been developed, and both comfort and speed have risen considerably. By moving the parts around and adding a streamlined shell, the current human powered speed record is over 80 mph. (Picture below)

Perhaps I was thinking too much of my own experience in dismissing the usefulness of electric bikes. From a purist's point of view, muscles ARE the batteries, and they have greater range and speed than the current commercial offerings. But, this holds true only for those who are fit, which sadly, isn't very many of us. So, for the vast majority of the population who'd rather not break a sweat when grocery shopping, electric bikes are a great idea. If it gets more people out of their cars, that's even better.

I've tried several e-bikes - my friend Gord owns a local bike shop and makes a point of stocking far more than mainstream stuff. He's always saying 'try this' whenever I visit. One bike was outfitted with a nuVinci drive, which is a copy of a Leonardo DaVinci design. It's brilliant, and very smooth, much like the 'no-shifting' drive of a Prius. Others had regenerative braking, which I really liked, and not just for the efficiency - they're powerful and smooth. I'm convinced electric motors are the way to go, but, as with hybrid cars, the limiting factor is still the weight of the batteries.

So, if you've got ideas for a carbon-fibre spring, or holding a static charge within a spiral of hemp, or a jet drive that runs on used cooking oil, let's hear it.

 

I haven't ridden these particular bikes, though I have purchased several Treks and am happy with them. I've ridden another bike with a similar electric system that boosts the power you put into it. The harder you pedal, the more assistance you get, and the level of power boost is adjustable. It works quite well, and I'm sure Trek has developed a reliable product.

 

I hadn't heard of nuvinci before. I have ridden a couple of bikes with the shimano internal planetary gear hubs, like the breezer bikes, and one sold at REI. I didn't get either one, because they didn't feel like they had a wide enough range or were very efficient, though I understand there are some higher end versions of the same thing that have been used on racing bikes. This nuvinci hub design seems to have some promise though, based on this review from a Seattle bike shop guy:

http://www.bikecommuters.com/2007/03/07/nuvinciâ„¢-internal-hub/

FYI, for those interested, here's the fallbrook technologies website, with pictures and video:

Fallbrook Technologies

 

Yeah, the Trek design appears to have the same characteristics and be well thought out. I'm sure you are a much more serious rider than I am. I just gave away my Trek 7500 hybrid because of back and wrist discomfort. It was a great bike though. I've now graduated to the Specialized/Globe Carmel 700 05 comfort bike, that lets me sit perfectly upright. The bike shops all stock the lower end 03 model, with lower end wheels and twister shifter, but I was able to order the 05 model, with better wheels, and slighter better components, including trigger shifters. A lot heavier than the Trek was, obviously, but so far I'm very pleased with it, as are my back and wrists.

I was curious about the Trek electric, after seeing it on their website. They do sell it in a comfort bike format (the 7200, which wasn't quite as comfortable as what I got). Since this is mainly for pleasure and exercise, and I don't want to commute on it, I didn't have any reason to consider going electric.

 

And not just in bicycles. I can see the gear range and smoothly variable power transmission being useful in all sorts of things, from power tools to farm equipment, manufacturing, and transportation.

Have you tried a recumbent? You might find a long wheelbase design with a mesh seat, like a Tour Easy, to be very comfortable.

 

I'll have to really be an invalid before I'll climb into one of those! The townie bike is working out just fine, thanks. Just got back from a ride as a matter of fact.

 

What? No, they're rather quick and very comfortable. Not for invalids in the least. A further refinement of the recumbent idea is the front wheel drive low racer. Does this look more like your speed? I think one of these would make an awesome touring bike.

 

Umm, it might be the antiquated design of the upright diamond frame bicycle that gave you your back and wrist problems. They may be efficient, but not very well designed for a human body. In fact, a recumbent is more efficient on the flats and downhills, and that's why they were made illegal on the racing circuits - because it gave their riders an unfair advantage. And somehow the average rider never realized their upright diamond frames (wedgies) are second-best technology, and so it has kept the foothold it had.

My next car will be a velomobile. Or maybe a catrike with a velokit, as a cheaper and more flexible option.

 

My wife and I ride a Double Vision tandem recumbent. If you want to see a long wheelbase, look at a tandem recumbent. I can't turn ours around on a normal two lane road. We stop, pick it up, spin around, and set it back down again.

Tom

 

Very cool, maybe I'll have to try one sometime! Always looked awkward and I would worry about being seen, though I guess that's what the flags on sticks are for. I did open my big mouth and say something about efficiency, and I do understand these are supposed to be efficient. But of course, I'm usually just wandering around anyway, not really trying to get any place in a hurry.