HyperBike: Hype or Hope?

i'd love to see this on thtv.

on the h.b. website, the footage of the inventor riding the bike showed him going pretty slow. i'd like to see the thing really go 50 mph.

looks cool though. if it does get made, it would be nice if it doesn't cost as much as a car.

One of the things I enjoy about biking is being nimble and able to zip around through small places that you can't go in a car. And being out in the air and out in nature. Being in a cage like this would destroy both of those qualities of the ride.

Where do the clowns ride? Seems to me the weight of that huge structure would kill any benefit from using your arms to pedal. On the other hand people in cars will have no excuse not to see you.

It won't make 50mph. That figure, from the interview on his Website, is simply saying "if you turn the pedals so fast, the gearing and wheel size would mean it would be making 50mph". But that doesn't make it physically possible to turn them that fast; it's just as much work to push a human-sized object through the air at a given speed no matter if it's a bicycle or one of these - although, of course, the aerodynamic profile of these is much worse than a conventional bicycle, with a completely upright rider surrounded by miscellanous hardware.

The other thing that slows a bicycle down is hills - now a production model probably won't weigh the 200 pounds of the prototype, but it's obvious that something with so much more structure will weigh more than a conventional bicycle.

Pressing the upper body muscles into service is an idea that's been mooted ever since the Victorian era. It doesn't work for two reasons. First of all, on someone of normal muscular development, the legs are much more powerful than the arms; the extra power the arms can provide does not make up for the extra machinery for the arms to push and the reduced efficiency of a more complex drivetrain. The real killer, however, is that the limiting factor on a regular cyclist's sustained power output is cardiovascular; the legs can use all the output of the heart and lungs, and so if the arms do work the legs do less work.

Crackpot vision,

This is a completely ineffecient, stupid idea. Who will want to go fast in this death trap? Impossible to store, cumbersome, can we now tear up all the bike lanes to accomodate something as stupid as this? I am going to
replace my car with this? And now where does my
wife and kids ride? A sack or groceries? When that wheel gets out of true how do I fix it? Flat tire? Cost effective? I can find hundreds of flaws, defects, and negative aspects to this product, and very few benefits. Yet another crackpot inventor so in love with their idea, that they are blinded to reality. Someone smoked a bit too much weed and drank way too much of their own kool-aid. Keep this kook away from the children!

This is more or less old news, or at least old wine in new bottles.
Several fully functional recumbent bikes have been built by Semcycle with wheels up to at least 11 feet diameter.
The chosen propulsion-methods have been various as well but mainly by conventional legg-muscle cycling-way.

These "dicycles" or "diciclettes" go back a long way (±1880) the recumbent version where thought up by Ir. C.S. Abrahams the father of Sem Abrahams (a multiple worldchampion and record-breaking unicylist and unicycle-artist) somewher in the mid 90's of last century. The differences between Semcycle-dycycles and there ancestors is that they do lack any front- or ack-support wheel, and that the cyist hangs recumbent-style below its central differential-axis. This makes the bike feature the possibilities of turninf 360º at will around its horizontal as well as its vertical axis.

For reverence look at http://semcycle.nl/img/dicycleS.jpg
or http://semcycle.nl/html/very-special.php

Thanks to Scott T for a dose of reason. This thing quite clearly cannot do what is claimed in the articles about it.

In addition to his points, I very much doubt that safety is enhanced. No, you won't flip over the handlebars, but what about traffic? Either you have to occupy an entire lane (creating road rage if you can't keep up with the cars) or ride to one side, where you will be too wide for cars to pass safely.

On top of that, with a high center of gravity and no way to bank for turns, this thing will be a worse rollover risk than the worst SUVs. That's if it actually goes fast, which isn't likely.

Unless of course they build roads for it on the moon. Then the lack of air could make up for the as-bad-as-it-gets aerodynamics of this monstrosity.

Steve Ryan
Ph.D. Aerospace Engineering and lifelong cyclist

Ms. Lepisto,
Thank You, you upheld my idea using only our first, primitive or working model prototype. It is in fact nothing more than a line drawing; a representation of a dream. Thanks also for describing how it may evolve.
Critics, strong words, thanks for raising some important issues. Apart from my own doubts and fears what drives me through this process and scares the hell out of me is that no one, including me, can ever know until it is developed into the mass production prototype, how the HB will perform given the combination of gearing, momentum, centrifugal force and sheer human power. I am committed to finding the answers. Critics and others' encouragement has brought me this far.
What I do know is NASA reps. were impressed by the broad base and low center of gravity relative to the wheels spinning axes. They also loved the open area within which a fully suited astronaut could propel the wheels unimpeded by a seat. Additionally they are confident in the development of a peddle linkage, sort of like a stilt which by pairing the power of a leg and arm on each side will bring into play the torso or core. As in swimming, the core coordinates simultaneous pushing and pulling adding its' own power into the mix. Unlike dicycles of the past and recumbents of the present where the ryder sits or lays out the HB is designed for the operator to throw body weight into each peddle thrust as when ascending a hill on a conventional bike.
STAY TUNED.

"Either you have to occupy an entire lane (creating road rage if you can't keep up with the cars) or ride to one side, where you will be too wide for cars to pass safely."

cars....what cars? The ones that have been pushed to the ditches because gasoline costs $1000/barrel? The future needs crackpot visionaries...I am glad there were not too many naysayers about before DeForest built this thing. DeForest, I salute you.

This is what it looks to to me- An old vintage bike from the 1880´s reinvented and built up in modern materials- In my native language (Dutch) we use the saying that from time to time the wheel gets reinvented by some people. We mean by this that apparently they do not check history first before they start doing some serious inventing themselves...

http://www.stamfordhistory.org/images/bikeclub2.jpg

To me- Hyperbike and the team that develops it, look more like an art-product and artists than serious scientific work. And as an art-product, I do salute this Hyperbike- Build it- develop it, invite crowds to see it, tape it all on video and then donat the whole thing to the Tate Modern or some other art-collecting museum that will be mighty happy to make it part of its collection. Therefore it absolutely baffles me that NASA has interest in this. NASA can´t be that ignorant that they do not know of far more realistic low centre of gravity energy efficient three wheel driven recumbent tricycles that are already fully developed and on the market as we speak, can they...?

Christine Lepisto asked:

# Is your first instinct that this is not a
# means of transportation but an exercise
# device that will soon be relegated to the
# ranks of many other gut-busting fads?

You must be a mind-reader, Christine: that is *precisely* my first instinct.

# Then ask yourself this: what would
# the inventor of the horse saddle have
# thought about a bicycle?

Since we have no idea who invented the horse saddle -- and it has no bearing whatever on the HyperBike -- the question is irrelevant and immaterial, just like the rest of your article.

# I am looking forward to making the first
# coast-to-coast crossing in the tandem HyperBike

Unless your tandem partner is The Incredible Hulk, that's not gonna happen. Try looking forward to something more realistic, like making a coast-to-coast crossing on a real bike, for example.

I have already one comment in waiting, but I´ll try again, adding some other thought- Mr. DeForest to me again seems an artist. He has some basic ideas that hold some ground. But then he builds his prototype in such a monstruous way that it is only marginally useable. It only demonstrates some of his theories. And then he immediately goes to the press to show his contraption. And I do not understand how, but some press and even some NASA-official pick up on it.

I can only gather that the folks who have taken attention to this idiocy or at best this basic conceptual sketch of means of motion never have gathered any previous knowledge on bicycles and bicycle history and they themselves move around in big SUV´s. Otherwise they would have seen history repeat itself in shape and even basic concept.

NASA would do good first to give closer attention to modern recumbent bike builders like for example rowing bike builder Derk Thys from the Netherlands than wanting to put taxpayers money into this embrionic artsy idea...

Okay mr. DeForest, I´ll grant you this- You did a fine job in getting attention. Now could you please tell us what is your trick in getting funds form formerly to be taken serious organisations like NASA (who to me are now laughing stock and prime target for ridicule) for such follies of yours...? I also have some ideas of my own that I think NASA would want to put money in... Wait- let me quick draw something in metal and welds...

Mr. DeForest- What I do not understand is that NASA seems to think there is no seat in this contraption. On the streamer on that site, I clearly see some form of seat being used. So apart from them being seemingly totally unaware of any real bicycle technology, they also have bad eyesight...?

Wow mr. DeForest- You are a True Magician i what you did with those NASA-people! Kudo's to you...! You must be a great Hypnothist or something like that!

The big question is, can this be developed into something that will actually be useful here on earth? It might work great on the moon where there’s not a lot of gravity or wind resistance, but here on earth, in its current configuration, it occurs as a big unwieldy and awkward contraption. Its silly little wheel in front rises up off the ground as the rider sways back and forth in what looks like a sea-sickening, swinging motion induced by the rider the of device being suspended by a harness!

It’s so zany – I Love It!

Could it be altered to be a stable (no more swinging), smaller recumbent that might have electrical power-assist for ascents?

But seriously, I think someone should build a horse-bicycle. Just think about it, a horse is a really powerful animal. If the Horse-icle were designed and built properly, utilizing proper material technology, gearing and steering, you could probably easily reach a top speed of 90 mph! You’d need goggles for yourself and your horse – maybe safety-belts and airbags too…

If I had more time and money, and a horse of course, I’d build one. Then I’d cruse around town on my Horse-icle and the blow the doors off all the Priuses in my neighborhood whist thumbing my noses at them for having a greener “ride” than they do…

As a triathlete and industrial designer, I would add that the Hyperbike will never become a mass market product. There are more efficient HPVs available that will fit in a garage for less money.

As an intellectual exercise, I commend the engineers and designers. There are some interesting ideas that may be adopted for niche markets. Maybe NASA. After all, with the bulky suits of planetary exploration, it would be impossible to lie down in the recumbant position and see where you are going. Standing, or something like it, would have definite benefits.

It is important for designers and engineers to stretch out and solve problems with unique solutions. Most never make it to market, but the ideas can live on and grow. Visionaries are almost always seen as crackpots in their time.

Regarding the bicycle, NOTHING will ever replace it. It is the most efficient, elegant transportation solution in the history of mankind. In a hundred and some years, no one has improved upon it with anything other than tweaks.

I think it's interesting. People (cyclists) are way too negative about new ideas, much as the Neocon Republican FUBARists are negative about anything that makes sense. Look at how long it has taken for recumbents to catch on, and they make a lot of sense for road riding.

That said, I think that it is way too big, and at 200 pounds, way, way too heavy. I'll bet you could get it up to 50mph + on the flats, but in start and stop traffic, or on hills, 200 pounds is 200 pounds here on Terra. That's way too much mass, especially rotating mass.

Those big wheels are going to be a PITA to start moving, even if they are made of unobtanium.

Look, I have two road bikes, a Trek OCLV and a Klein QPro. It makes me happy to ride sixteen pounds worth of carbon and aluminum, and in the winter I put them in front of my fireplace where they look sexy. I couldn't get this bike in my garage, let alone my house, so I'd be forced to leave it outside in the winter and put Christmas lights on it. That isn't sexy.

Hey Tucowed: why don't you quote the part about:

"Drop your prejudices and hesitations for a second, and give Curtis DeForest some credit for thinking outside the box"

Just enjoy the inspiration, like a fellow inventor, or if you must point out the many drawbacks of this crazy scheme (at least here on earth), then try a soft touch. Your homework: read David L Allen above.

It is a prototype. You gotta give the inventor credit for getting it that far. I s'pose you all got better ideas?

Did all the negative people even comprehend what they read in the article? This guy isn't trying to build a better bicycle, he has invented something unique. It doesn't look anything like a bicycle or operate anything like a bicycle. It is not a bicycle. The poor guy put the word "bike" in his invention and all the lame cows of the population compare it to a bike. You make me sick. NASA is interested in this thing for low gravity applications. Like the Moon or Mars
Mr. Aerospace engineer. So go ahead welding boy weld away. I don't think your time could be spent better. Why don't you all go read the article again.

Oh but Randy- I do believe did read this article well enough!
I personally agree that we are not talking strictly bicycles here- if only in the sense that a bicycle has only 2 wheels, whereas this contaption at best is a tricycle.
Okay- So we established that this is not a bicycle, but rather falls under the bigger nomer of a HPV- a Human Powered Vehicle. Yet does that make any difference in how we perceive this looney contraption...?

About the inventor himself is being said: "recognizes that major drawbacks of the modern bicycle include the exposure of the rider to accidents and the limited speeds which the average cyclist can maintain. The conventional bike places the weight of the rider above the wheels' spinning axis, an inherently unstable situation (as any cyclist forced to stop fast well knows). Also, conventional bikes use only leg-power, carrying the upper torso as dead weight. And did someone mention saddle-sores? HyperBike solves all those problems."

So Randy - How much more extra encouragement do we need to do some comparing to a bicycle when mr. DeForest does it like that himself...? at least 4 direct comparisons and mentionings of the bicycle himself...! Now- Any landbased human powered vehicle will inevitably be compared to the bicycle, since that is one of the most power-efficient means of transportation humanity has ever invented. So wether you Randy like it or not- If even mr. Deforest starts to compare his unique machine to the conventional bicycle, all the rest of us negative bickerers do have all the rights in the world to follow that line also...

NASA might be interested because of the low-grav applications, but then again I say- Take a good recumbent trike or even quad, rebuild it in such a manner that it is fit for an EVA-rated suit and hey presto- you have the same qualities as the Hyperbike, at probably a fraction of the needed stowage area and development cost AND you have more guarantee for success because that kind of recumbent bike has already proven itself with low centre of gravity, good speeds and no horsesadle like seat, unlike the Hyperbike that sofar ony has proven that it is heavy and big and cumbersome...

Perhaps Randy it is you who should do some extra looking into this matter before you counter us....?

By the way- I ride a Trek S200, a Micro Bike folding bike, a FlevoTrike, a FlevoTrike and an Alleweder. The last 3 vehicles being a recumbent bike, a recumbent trike with big luggage compartiment and a recumbent trike fully faired streamliner. Because for about 6 years I rode 24 kilometers from home to my job and 24 km back about 350 days per year come rain or snow or wind or sun, I dare say I do have some experience in what any HPV has to be able to perform or look like to do a set task.

Cheers!

jayjay asked:

# Hey Tucowed: why don't you quote the part about:
# "Drop your prejudices and hesitations for a second,
# and give Curtis DeForest some credit for thinking
# outside the box"

I'd rather drop my drawers and give Curtis DeForest the moon for not knowing what's inside "the box" before trying to think outside it.

===Editor's Note:===
This HPV prototype has certainly stirred up controversy. Thanks to all for sharing your fascinating viewpoints, but it seems time to remind all commenters:

Commenters should keep in mind that other commenters are human beings. TreeHugger wants to create an inclusive atmosphere that encourages everybody to join the discussion. Please be constructive and tactful, write as if you were speaking face to face. Even strong criticism is more effective when polite and restrained.

I came to this link from "space.com," and am fascinated by all of the comments. There seem to be a lot of people who are seriously angry at Mr. DeForest for...what? Trying to invent a safe, clean vehicle? No, my guess is that people are upset because he got NASA money. Perhpas money that they believe he doesn't "deserve."

Someone mentioned the Republican Neocons in an above comment. Well here's one thing that the Neocons know, that the "liberals" can seem to learn no matter how many elections we lose (and yes, we did lose the last two, despite any polls, because who's the frickin' President?), and no matter how messed up this planet gets.

You don't turn on your own.

He's not building a better bomb, for christ sake. He's not trying to create a better way to cut down trees, or to drill deeper for oil. He's just trying to build a better HPV.

Well I say that anything that can get government agencies to put money towards clean transportation is great. Better than great. Even if he doesn't have a single new idea (and honestly, I can't say one way or the other about that), he's drawing attention to the possibilities.

All of you with your recumbent bikes that you're so proud of? Why aren't you out there talking to NASA, if your ideas are so great? If you know how they should be spending their money, why aren't you pitching your vision? Do you actually have one? What are you doing that is as significant as convincing NASA to consider replacing motorized transports with HPVs?

Why is it that people have so much energy to put into knocking others down, and so little energy to put into lifting others up? I salute Mr. DeForest and his commitment to his vision, no matter what the final result.

David, You're right. Of course. But what bothers me personally and why I react rather overly is because I have the impression that this Hyperbike thing has gotten the wrong kind of attention.

To me it sounds a bit like that film "Forrest Gump" about this mentally retarded guy that gets taken completely out of proportion and is taken so seriously that even the President listens to him. While all the time he's just this mentally retarded guy that only does his own thing.
Now I do not want to compare this Hyperbike man directly to Forrest Gump. Far from it in fact, but I certainly do have the feeling that this guy is way-way-wáy to early in presenting his ideas to the world. To me this looks like art with some vague scientific hint to it instead of serious science based prototyping. And so- Fine- call it art. And if it is called art- Lots of kudos to the Hyperbike. Put the driver in a fancy costume and go to Fairs and art-events and hey presto- you have a fantastic product that even could earn a buck or two.

I think the reason why most of us recumbent bike addicts do not go to NASA with our ideas is because first of all probably most of us have some kind of notion that this whole idea of going back to the moon is lots and lots of wasted time, energy and funds that better could be used to solve ecological problems here on our own planet. I only have to mention Al Gore and his point of attention to make myself clear on this issue... Second in my personal view NASA does have ample other means at its disposal to make fine moonbuggies that are propelled by solar energy and what not.

Because of these two reasons I would not want to be connected to NASA for recumbent bikes or any other moonbound HPV. Stupid on my part perhaps, yes, because probably I could earn far more cash than I do in my current jobs...

:-) !

Okay Foreigner1 am I to understand that and I quote “I think the reason why most of us recumbent bike addicts do not go to NASA with our ideas is because first of all probably most of us have some kind of notion that this whole idea of going back to the moon is lots and lots of wasted time, energy and funds that better could be used to solve ecological problems here on our own planet. I only have to mention Al Gore and his point of attention to make myself clear on this issue... Second in my personal view NASA does have ample other means at its disposal to make fine moonbuggies that are propelled by solar energy and what not.

Because of these two reasons I would not want to be connected to NASA for recumbent bikes or any other moonbound HPV. Stupid on my part perhaps, yes, because probably I could earn far more cash than I do in my current jobs...”
Because If that is how you feel you my friend you might want to look a little into just what the space program has done for this country and very much so the world.
Granted allot of us think going back to the moon is silly and a waste of this countries assets along with taxpayers money. That is still no excuse not to put your ideas out there
Now im not going to claim that his invention is new or even that valid in this world or any other my point is that. This gentlemen put himself and his mind center stage in a world that has nothing but ignorant things to say about others and there doings when the people saying the ignorant things do nothing but sit back and make excuses as to why they aren’t out there changing the world or at least trying to

Now forgive me for my grammar because it was never a strong point of mine.
I just thought I would put this out there with nothing but respect for you and all other life on earth but I mean it when I say “you can talk the talk but can you walk the walk” because if you have so many ideas that could change the world and better human life and I think we all agree that putting a stop to our reliance on fossil fuels will make human life that much better and I quote “an economy that is based on fixed resources will devour itself” not to mention the benefit to you and I quote once more “because probably I could earn far more cash than I do in my current jobs...”

Now can you give me a good reason now why you shouldn’t .without picking on my grammar because believe me when I say it you wouldn’t be the first.

P.S. thank you for your time and I apologize if I offended you or any one else

Hi John Mears- Thank you for reacting. No I won't pick on your grammar- I myself am not a native English speaker (I'm Dutch), so I am sure that the language I write here will not be faultless too. ;-)

My answer to your question would be as follows- Currently I have 3 jobs just to pay my bills. I am convinced that not everyone has the opportunity to just find a nice cushy job that gives enough earnings to just live out dreams and principal convictions. Going ecofriendly in our current consumer society does cost extra money. But then again- I try somehow. I can barely scratch out a living, but I feel I try to do my part for my community while at the same time I am happy at what I do.

Aside from that, recently -that is to say starting the last 10 years- I started to gain ecological conscience. I firmly stand for the message that If you have ideas and convictions on this issue, you better start with yourself and in that way give an example to your neighbours.

For me, that means that I share my motorised transport with others and that all oneway distances upto 25 kilometers, I do by human powered transport (hpt). Aside from that I have equipped my home with stuff like separated watersystems -rainwater for the toilet- extra heatcontainment and reduction of the use of energy for heating and electrical appliances. I seriously try to reduce my outpoor of waste and I have separated wastedisposal for plastics, paper, metal and vegetable/meat residue. I reduced on the consuming of meat. I stopped going to fastfoodrestaurants, I practically stopped consuming in that most of my clothes come from eco-friendly manufacturers or come from secondhand shops. I never go on holiday by airplane- even if I have the opportunitiy to do so, I choose to go by hpt. I know I can do better and so I strive to improve like a hobby.

I do understand the benefits of going into orbit for humanity in the sence that sattelites help give us better view and understanding of the ecological problems on our planet and even the connection between exo-planetary exploration and the knowledge and understanding of the ecology of our own planet.

But I still do have a hard time believing that it is so important to put fixed bases on the moon and to let hpv's roam up there. For that same money- put up some more sattelites up there that can help us understand what is going on down here on earth.

Is that enough answer?

And you...? What do you do in this respect? Can I learn from you?

John Mears- I've tried to answer you a few days ago but my posted comment was not placed -I guess by the Sysop here. (PLEASE SYSOP: If you have a reason not to place a comment- be so kind to communicate the reason for denial to us...?) So I try again-

I understand that NASA hangs sattelites in orbit to scrutinize our planet. I can even comprehend why they send machines to Mars and beyond, because those explorations can shed light on how the ecology on our own planet functions. In that light, I can not understand why we should need people live on the moon. If they can be productive and earn cash up there, I will have no further objection. But sofar there seems not to be any such thing.

As far as jobs are concerned and why not go to NASA or something like that- I have 3 jobs. I barely scratch out a living with them. Not every one is so fortunate just to be able to "take" a cushy wellpaying job. So, like so many others I try to do as best as I can with my ideas in my own life. And only for my neighbours and my friends I hope to be some inspiration or some small form of example on how you can come without using your car for every small thing you have to do. And so I try to cut down on water use by using rainwater for the toilet. I try to cut down on electricity by using special lamps and some solar panels. And so I use my bikes and take time to explain things when asked by people who do not understand me.

That is how I see things.

Ah- And John- Don't bother about your grammar- I'm not a native Enlish speaker, so most likely you outdo me in writing correctly. I'm Dutch. ;-)

It's well........

I'm a bit disappointed that we are not discussing more what the inventor of the saddle would have thought. Of course, one should stipulate whether that be pre or post stirrups (sort of an equivalent to toe clips so that you could better drive your lance into that dasdardly villager standing between you and pillaging/conquering), but one can only think that Mr. Saddle would give the bike two thumbs down. Besides the fact that the roads would have been terrible even for bikes with rubber tires, imagine trying to sweep into to a battlefield after your shieldmate has been unbiked and pulling him up behind you as you pedal off to fight another day. No thank you. Any self-respecting horseperson would definitely think the bike far too freaky for any type of utility in their day. I suppose, in a similar vein, that's the way most motorists look at bicycles now.

To foreigner1:

Sir, I commend you on your ecological lifestyle. We must all become serious about improving the efficiency of every polluting activity by human beings from birth through death.

I'm curious about one thing though. Why are you using a computer, a non-essential activity in your simple energy-saving life?

In fact, why do we waste so much energy and money trying to find GENETIC cures for diseases? Why would we want to prolong the lives of people that are adding to this crowded planet, using resources, polluting, consuming OXYGEN????

Please sir, if I may say so, we would all have life expectancies of about 20-25 years if we thought like yourself, and we would be hunter-gatherers.

You seem to be benefitting from some spectacular technology in your own home by employing technology that was INVENTED by people like Mr. DeForest. If it were not for visionaries with ideas to change things, we would all be serfs living in the clutches of dictators who believed the earth is flat and the sun rotates around the Earth.

Enough said, sir.

Thank you. Charlie from New York City:

(I'm driving to the airport in my SUV at midnight to catch a flight to San Diego). I'm happy the heat works GREAT, because it's going to be around 18 degrees F tonight!

this blows the concept of "share the road" right out of the water... if many of these showed up, I'd bet 10-1 there would be by-laws passed to restrict them...

Rather than say this is a good idea or a bad idea, how about we look at the particulars and say what might be good or not as useful?

If the whole-body participation and sling instead a seat allows better ergonomics for some types of use, that's certainly a useful thing.

The concept of the user inside what is effectively a roll cage (no pun intended) might be useful as well--though some recumbents do that, as does the BMW C1 motorcycle, without being so big and cumbersome.

Then there's the idea of the huge wheels and having the center of gravity below the center of rotation. That is not useful. What matters for stability and braking is not the center of rotation of the wheels, but the relationship between the contact points with the road and the center of gravity: for braking, it's how far out in front that little wheel is, vs. the height of the center of gravity. For cornering, the width between the two outer wheel contact points. You could accomplish the same on both counts with conventional size wheels. The you could make prototypes to try out the whole-body pedaling and sling and so on with much cheaper prototypes. With or without roll cages.