Eric Birkhauser’s ZIPcycle share concept

Commuter, Concept, Electric bike 26 18

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  1. Mzungu October 11, 2012 at 2:48 pm -  Reply

    I know it’s just a adv. concept and all, but how am I suppose to hold on to the handle bar thing that he had on there? It looked like it should sweep back not forward….. That pointy handle bar and stem junction would make some lawyer really rich. :-)

  2. Max Power October 11, 2012 at 4:22 pm -  Reply

    The EPCOT fan in me loves the look of the bike and station.
    However, would the general public warm to the idea of a recumbent velomobile based bike share? A lot of the appeal of bike shares in US cities is the European-ness of the upright city bikes (“I’m Mary Poppins and Audrey Hepburn!”), and recumbents and velomobiles are synonymous with weirdos and nerds (no offense to my fellow weirdos and nerds). I think it would be a hard sell.

  3. Impossibly Stupid October 11, 2012 at 4:54 pm -  Reply

    Just a non-starter through and through. Costs of custom bikes will be too great, and the inconvenience of centralized stations will be too time consuming. And many, many other issues that are obvious to anyone who actually bikes a lot (especially on recumbents).

  4. rjnerd October 11, 2012 at 5:37 pm -  Reply

    The handlebars besides an ergonomic disaster (hands aren’t angled that way) are outright dangerous. You have a point (it even looks arrow like) aimed straight at the riders chest. On something intended for urban use? Can you say sucking chest wound? I suppose underseat steering is too out there to those that haven’t tried it, but it is much more comfortable, on top of safer.

    It is nice to have an “outsider” designing bikes, as the insiders get stuck making tiny tweaks to the status quo, but anyone that is trained in design should be aware of basic ergonomics, and aware of the standards already established by the vehicle design community (thinking the auto industry) as to what not to put in a cockpit, like spikes aimed at an occupant.

  5. Eric Birkhauser October 11, 2012 at 10:14 pm -  Reply

    Thank you very much for the feedback, these first glance thoughts are exactly what I am looking for. Your critique is greatly appreciated.

    Mzungu, so the idea is to utilize an integrated shifter, brake, and acceleration lever. These functions will be incorporated into the upper lever, the bottom bar is the handlebar. Yes the handlebar will grow in diameter from what is shown. For the first working prototype a standard road-bike handlebar will be used. Indeed the stem and handlebar junction have bit of a point, rounded in section, but nonetheless, I will modify to attempt to avoid litigation.

    Max Power, great question. I agree, we may be a way off from seeing a recumbent share program in a modern city. But to achieve a shift in thinking about active transit solutions, a proven means of reducing transit times must be offered into the conversation. And yes I agree, the recumbent and velomobile desperately need a rebrand. The aesthetics of the zipcycle are an attempt at the elegance and sensuality we expect from the automotive industry. To gain traction in the public, style is everything. From advertising campaigns of Nike to Lululemon making Yoga appealing, just about any athletic activity can be transformed into a fashion event. I am confident if there is truly a logical argument for this approach, active transit systems can be spun into the next trend.

    And Impossibly Stupid, yes cost is a huge component of this concept. People do not really consider the bicycle a viable transit alternative because the average cruising speed of a cyclist is 12 mph. Fast bikes, whether they be recumbents or not, are always expensive. Bike shares really work, city by city, they are becoming a truly proven means for getting people back on bikes for commuting. To double that average speed, making a bike competitive with the automobile and mass transit, there is a price point. Approaching the cost through a sharing program resolves this in two ways; it disperses the cost over the membership pool and with a large system, mass production will dramatically drive costs down. While the first prototypes will be expensive carbon and foam one offs, the zipcycle production chassis would be stamped out of aluminum, as many automobile body panels and frames are being done today. As a 30 mile a day daily commuter, I am making the first prototype for myself, to work out the kinks, which I am certain, as you mentioned, there will be many.

    Again, thank you very much for the feedback, my best to you.

    • Impossibly Stupid October 12, 2012 at 12:54 pm -  Reply

      “To gain traction in the public, style is everything.”

      You fail to truly understand design if you think that is true. The landfill is littered with products that put style ahead of usability. And when it comes to biking, it is not mere fashion that will get people pedaling. For example, your seat immediately looks like a river of sweat to my eyes, because I’ve ridden on recumbents without mesh backs that offer reasonable air flow. It will take all of one ride for the public to no longer be interested in your oh-so-important “style”.

      “People do not really consider the bicycle a viable transit alternative because the average cruising speed of a cyclist is 12 mph.”

      That is very low on the list on excuses people have to not ride. Most people prefer not to sweat when they arrive somewhere (note that these are excuses, not necessarily reality). Most people with big asses find bike seats to be painful. Most people don’t want to wear that weird clothing that cyclists wear. Most people don’t want to be exposed to the cold or rain. Most people don’t want to breathe in awful exhaust fumes from the cars on the road. Most people are intimidated by larger vehicles. Most people want to be better protected in the case of an accident. Oh, yeah, and maybe it’s also a bit slower to bike somewhere, too (if you don’t really think about the time-cost tradeoffs).

      “Fast bikes, whether they be recumbents or not, are always expensive.”

      There are no such things as fast bikes. If someone is a 12mph commuter, they’re still not going to be breaking any records because you give them a $2K race bike or your super-slick $5K recumbent. They’ll certainly go faster, but more like 15mph, not 24mph.

      And any advantage you might see in speed is lost in getting the bike from a station. We have a fairly well built out bike share in Minneapolis already, but I’m still a 15 minute walk away from one at home, and who-knows-how-far away at my destination. For what might be a 20 minute ride to downtown, you’re going to have to build a bike that is a minimum of 4 times as fast to merely break even. Difficulty: even in a car you can’t (legally) get downtown in 5 minutes.

      Like I said, it’s essentially a non-starter. Vehicle shares of any kind don’t really work for transit, because peak usage has commuters pretty much all going in the same direction at the same time. You’re never going to be cost competitive if you have to start it by managing a fleet of expensive custom bikes. And you’re certainly not going to get fat, lazy Americans biking (and walking to get to your bikes) just because it’s a slick looking machine. You need to start with reality when you do your design.

  6. J.L.Garrett October 12, 2012 at 1:18 pm -  Reply

    I think its a genius design with style. Let the sheep buy the same old looking bike design. General public has decided design in everything and it gets us no where.

    We didnt need the iPhone, but Steve Jobs showed how nice it is to have it.

    • Eric Birkhauser October 12, 2012 at 9:05 pm -  Reply

      J.L.-

      Thank you for you kind words, I think a zipcycle would be nice to have as well!

      Eric

  7. Eric Birkhauser October 12, 2012 at 3:05 pm -  Reply

    Cheers Rjnerd, point taken, literally. I feel a bit of an open chest wound coming on right now. It can be rough being the outsider, especially when the hazing committee is on a bent. Thankfully a career in architecture has thickened my skin.

    But in all seriousness, I do really appreciate the feedback. This is a learning process for me, and vetting from the experts such as yourself will go a long way, especially before the file goes to the CNC. I have put a massive amount of time into researching the best ergonomics, and the current layout is not at all dissimilar from a number of products currently on the market. I will post some drawings showing this work to my website in short order. Again thank you for your time and insight.

  8. Eric Birkhauser October 12, 2012 at 8:59 pm -  Reply

    Insanely Stupid, thank you for taking the time to share your thoughts and critique. There were a few points that I would like to make in response,

    “…interested in your oh-so-important “style”.”

    My intent has never been to create something stylish, but to elevate active transit alternatives. My point is that style becomes a necessity in spinning the notion into an attractive solution in the public mind.

    This concept is not showing a foam back pad, which would be an absolute necessity. The final seat will be adjustable to accommodate a variety of torso sizes.

    “…maybe it’s also a bit slower to bike somewhere, too.”

    Indeed the obstacles involved in increasing ridership are immense and overwhelming. And the majority are infrastructure related which is another issue altogether. But some of these issues have to do with the bicycle and its availability.

    “…15mph, not 24mph.”

    So two things; aerodynamics and electric assist. Aerodynamics have a dramatic effect on the average cruising speeds. Anyone who has bought an aero set of wheels will swear by it. While speeds achieved by the Battle Mountain folks are not attainable or safe by the general public for commuting purposes, the principles and lessons learned from those achievements can be applied to the everyday commute. Pushing cruising speeds from 12 mph to 60mph is absurd, but 12 mph to 25mph with a safe bicycle-only transitway is feasible. And for the less physically active an electric assist can allow for acceleration to said higher cruising speeds.

    “…get downtown in 5 minutes.”

    To be effective stations must be evenly dispersed according to population density; but the quantity and location of stations will always be a limiting factor in a share approach. This is an issue you encounter in any type of transit design, and typically its resolution is best found in progressive planning and transit oriented development. But beyond the urban design component, the heliotrope station is intended for member and private bikes, standard and recumbent alike. So if you cannot afford a 5K bike, you can afford a membership, and if you can afford the cost, then you have the privilege of skipping the walk to the station and ride directly to your secure parking station and destination. Also, not shown with this concept, smaller at grade rack stations, akin to existing bike share stations, can fill gaps in the network.

    “…start with reality when you do your design.”

    It is not possible to get everyone out of their cars and on a bike, but if other alternatives are viable, safe, and attractive, a certain portion of the population may trade the gym membership for a zipcycle membership. The goal here is not to get the entire population out on active transit systems, but to move from 2% commuting by bike (here in DC) to 10%. Such a shift would be an enormous accomplishment. As most American cities are the result of decades of automotive based transit planning, approaching the issue of sprawl is critical. As cities take a long time to change, this concept is an exploration of reducing these distances by augmenting performance. I think we are all cyclists here in this forum, we have drank the Kool-Aid, so the question I ask is how can we successfully and safely grow our community while enriching the potential of we consider the best way of getting from a to b.

    • Impossibly Stupid October 13, 2012 at 1:43 pm -  Reply

      “My point is that style becomes a necessity in spinning the notion into an attractive solution in the public mind.”

      No, it doesn’t. The first order of business is showing a solution that beats alternatives in reality. Style is an “it’d also be nice” not an “everything” (which you stated emphatically, but have now abandoned for some reason). The fact remains that your making things “attractive” does so in a way that shoots costs through the roof, but doesn’t add much in the way of comparative utility.

      “This concept is not showing a foam back pad, which would be an absolute necessity.”

      No, it’d be an absolute deal breaker! Like I said, I have ridden recumbents quite a bit and without a mesh back their seats are just sweat machines. A foam back is just an insulator that worsens the problem. And the streamlined bike itself insures that there will be even less airflow to help cool the rider’s back. It’s a loser; rethink your design.

      “But some of these issues have to do with the bicycle and its availability.”

      Not many. There are plenty of people (in the US, at least) that buy bikes and just let them sit in their garages. You could probably give bikes away for free, even your super-slick one, to anyone that asked for them and see very little increase in riding. About 0.00% of the issue is solved by having bikes at pay stations you must walk to before you can go somewhere.

      “So two things; aerodynamics and electric assist.”

      I’m well aware of the fantasy of both, but I’m firmly grounded in reality when I take them into account. Proper aerodynamics take more effort than just a streamlined bike shell, and even then the biggest benefit is at higher speeds. Since your design is not fully faired, I have my doubts that it will be as efficient as you hope (and I also worry about how it would handle in a gusting cross wind, but that’s another issue entirely). So, yeah, someone who rides a lot might be able to push it up to 25+mph on a casual commute, but I have serious doubt that the infrequent 12mph rider is going to see much benefit. I really do hope to be proven wrong on that point, though; build it and we’ll see.

      As far as electric bikes go, I have long been of the opinion that current technology is not where it needs to be for bikes. They add too much weight and complexity to the bike compared to what little boost you gain. Your shell is already a highly vulnerable (and likely highly expensive, as well) component of your design, so you’d better think twice before you put a lot of extra weight inside it.

      Further, you need to think about this as more than just a bike issue. That is to say, people *already* have the ability to use a two wheeled, powered vehicle to get from place to place at relatively high speeds, both in the form of scooters and (even faster) motorcycles. They’re not using those much as it is, and I doubt they’d be using them more if they had get one at a shared station. At the same time, car shares and rentals are doing OK. You need to incorporate the implications of *all* of that if you really hope to offer alternatives to current transportation models.

      “To be effective stations must be evenly dispersed according to population density”

      And that’s why they generally will not work, ever. You can only “share” exclusive resources like this when the density remains relatively constant. If 10 people want to get from the West Bank of the U of MN campus to the East Bank, for example, that would be a viable scenario for sharing, because it would be balanced out by 10 people wanting to go the other way within a short time period. And that is something that will be repeated many, many times throughout the day.

      But there is little sharing to be had when you have 100 people who are widely dispersed in the suburbs that want to get downtown, work there for 8 hours, and then expect to be able to get a bike to ride back home again. To get any sharing, you have to haul bikes around by truck (as the local bike sharing system does) to fill the usage gaps, which ultimately turns it into a silly mass transit system for bikes!

      “I think we are all cyclists here in this forum, we have drank the Kool-Aid, so the question I ask is how can we successfully and safely grow our community while enriching the potential of we consider the best way of getting from a to b.”

      Sure, and that’s why I like to see any efforts to tackle the problem. But to actually *solve* the problem, you have tackle it with a healthy dose of reality. In reality, grand visions such as these don’t provide people with the small steps that are *necessary* to change their behavior slowly over time. I mean, hell, I can’t even deduct milage for taking a bike somewhere for business, but I could if I rode a damn car! Are there *any* incentives to riding a bike coming out of DC? Property tax rebates? Mandated health insurance rate reductions? If anyone there were really serious about quintupling the biking population, there are so many better ways of doing it.

      • Eric Birkhauser October 14, 2012 at 1:54 pm -  Reply

        Insanely Stupid, again thank you for taking the time give your critique, here are my thoughts,

        EB “My point is that style becomes a necessity in spinning the notion into an attractive solution in the public mind.”

        IS “No, it doesn’t. The first order of business is showing a solution that beats alternatives in reality. Style is an “it’d also be nice” not an “everything” (which you stated emphatically, but have now abandoned for some reason). The fact remains that your making things “attractive” does so in a way that shoots costs through the roof, but doesn’t add much in the way of comparative utility.”

        So we may have to agree to disagree, a positive public perception or style is absolutely essential to the success of a product. That being said, you are absolutely correct, it must be qualitatively better, I am working on that!

        EB “This concept is not showing a foam back pad, which would be an absolute necessity.”

        IS “No, it’d be an absolute deal breaker! Like I said, I have ridden recumbents quite a bit and without a mesh back their seats are just sweat machines. A foam back is just an insulator that worsens the problem. And the streamlined bike itself insures that there will be even less airflow to help cool the rider’s back. It’s a loser; rethink your design.”

        Alright, I will give mesh a chance, thank you for your patience and persistence.

        EB “But some of these issues have to do with the bicycle and its availability.”

        IS “Not many. There are plenty of people (in the US, at least) that buy bikes and just let them sit in their garages. You could probably give bikes away for free, even your super-slick one, to anyone that asked for them and see very little increase in riding. About 0.00% of the issue is solved by having bikes at pay stations you must walk to before you can go somewhere.”

        For better or worse, walking is an essential component of all forms of mass transit, it is unavoidable. The best strategy for alleviating these issues is through transit oriented development.

        EB “So two things; aerodynamics and electric assist.”

        IS “I’m well aware of the fantasy of both, but I’m firmly grounded in reality when I take them into account. Proper aerodynamics take more effort than just a streamlined bike shell, and even then the biggest benefit is at higher speeds. Since your design is not fully faired, I have my doubts that it will be as efficient as you hope (and I also worry about how it would handle in a gusting cross wind, but that’s another issue entirely). So, yeah, someone who rides a lot might be able to push it up to 25+mph on a casual commute, but I have serious doubt that the infrequent 12mph rider is going to see much benefit. I really do hope to be proven wrong on that point, though; build it and we’ll see.

        As far as electric bikes go, I have long been of the opinion that current technology is not where it needs to be for bikes. They add too much weight and complexity to the bike compared to what little boost you gain. Your shell is already a highly vulnerable (and likely highly expensive, as well) component of your design, so you’d better think twice before you put a lot of extra weight inside it.

        Further, you need to think about this as more than just a bike issue. That is to say, people *already* have the ability to use a two wheeled, powered vehicle to get from place to place at relatively high speeds, both in the form of scooters and (even faster) motorcycles. They’re not using those much as it is, and I doubt they’d be using them more if they had get one at a shared station. At the same time, car shares and rentals are doing OK. You need to incorporate the implications of *all* of that if you really hope to offer alternatives to current transportation models.”

        I have developed a membrane fairing for this concept and yes the drag coefficient reduction is substancial ( http://birkhauserdesign.com/blog/2012/9/5/120905-zipbikeprocess ). But from previous feedback on a velomobile concept on issues of ventilation and practicality, I am reluctant to make the fairing an integral component of the share design. I prefer for it to remain an option for private ownership. Nonetheless on the topic of aerodynamics, until a prototype is built, it is all just computer simulation.

        Making the assist package purely optional would allow riders of different physical ability to choose added weight and assistance or lighter weight pedal only approaches. An in-hub battery and motor package would allow for system flexibility based on the preferences determined by members. I must stress that the assist would aid acceleration to higher speeds and maintaining said speeds, but a electric assist speed governor is a must, as this would not be an electric motorcycle share strategy. The concerns of safety will make it difficult for any type of motorcycle share program to be successful. With a grade separated infrastructure, the real and perceived safety of bicycle transit systems is dramatically better. Great tip, a study of the Car2Go and zipcar business model will prove helpful in my process.

        EB “To be effective stations must be evenly dispersed according to population density”

        IS “And that’s why they generally will not work, ever. You can only “share” exclusive resources like this when the density remains relatively constant. If 10 people want to get from the West Bank of the U of MN campus to the East Bank, for example, that would be a viable scenario for sharing, because it would be balanced out by 10 people wanting to go the other way within a short time period. And that is something that will be repeated many, many times throughout the day.

        But there is little sharing to be had when you have 100 people who are widely dispersed in the suburbs that want to get downtown, work there for 8 hours, and then expect to be able to get a bike to ride back home again. To get any sharing, you have to haul bikes around by truck (as the local bike sharing system does) to fill the usage gaps, which ultimately turns it into a silly mass transit system for bikes!”

        Great point, on the mass transit system for bikes… a humorous one at that. People in areas of higher density will always have better access to mass transit, and can better serve bidirectional efficiency of the system. For the people in areas of low density a longer walk or private ownership is a reality, so the benefits must outweigh the drawbacks. Sadly we do exist in a cultural of denial. The benefits of any mode of active transit from a standpoint of healthcare costs alone is astonishing. That we are complacent with the fact that the leading cause of death in this country for individuals between 3 and 30 is automobile related, is truly incredible.

        EB “I think we are all cyclists here in this forum, we have drank the Kool-Aid, so the question I ask is how can we successfully and safely grow our community while enriching the potential of we consider the best way of getting from a to b.”

        IS “Sure, and that’s why I like to see any efforts to tackle the problem. But to actually *solve* the problem, you have tackle it with a healthy dose of reality. In reality, grand visions such as these don’t provide people with the small steps that are *necessary* to change their behavior slowly over time. I mean, hell, I can’t even deduct milage for taking a bike somewhere for business, but I could if I rode a damn car! Are there *any* incentives to riding a bike coming out of DC? Property tax rebates? Mandated health insurance rate reductions? If anyone there were really serious about quintupling the biking population, there are so many better ways of doing it.”

        You are right, we must crawl before we can walk, but the notion of walking gets us to crawl. In the field of architecture, the challenge is the same. We can design and fabricate buildings that are energetically positive, but without strong incentives we are forced into designing projects just a little bit better than the standard convention. You are absolutely right, it takes serious policy to effect change, but without landmark buildings in the arena of sustainability, the populace has an intense difficulty in accepting that dramatic positive change is possible. If we begin to visualize the true potential of active transit systems, it can gain traction in the public mind. While this concept may be a ways off from our current reality, my aim is to shift the center of the conversation by aiding in the visualization of our potential.

        • Impossibly Stupid October 14, 2012 at 9:41 pm -  Reply

          “a positive public perception or style is absolutely essential to the success of a product”

          Countless existing examples show you’re wrong. There is nothing positive or stylish about everyone being stripped and/or groped by the TSA in order to fly, but people put up with it because flying has clear advantages over taking a train or driving (in certain situations, for those people). All sorts of terribly ugly cars sold well in the 70s because they got good gas milage during an energy crisis. If someone invented a teleporter that required you to be slathered in bat guano, you can bet there would still be people lined up to crap-zap themselves to the other side of the world.

          A focus on style is a bankrupt design. Sure, you’d *want* things to be as appealing as possible, but you need to start with a fundamental concept that is realistic. Your just introduces too many new things to be cost effective, and it retains the same fatal flaws of other failed systems.

          If I were to suggest one thing to focus on, it would be the bike. I looked at the world records for recumbents (http://www.recumbents.com/wrra/records.asp) to see what real difference a tail fairing really makes (I expect that’s how your bike would be categorized). In *every* case but the 1 hour time trial, the weight of the fairing seems to slow the bike down, and there is only a negligible gain for the 1H. Even then, you’re looking at a 33mph performance put out by an elite athlete going non-stop the whole distance, which makes your aim of turning a 12mph commuter into someone who can easily see 24mph quite suspect. If you really have good reason to believe your bike can achieve the gains you claim, you should be able to shatter those records.

          “For better or worse, walking is an essential component of all forms of mass transit, it is unavoidable.”

          Not so. I usually bike to any bus or train stop (when I can’t just bike the full distance faster); in a more lazy world people could take electric scooters or skateboards. But that highlights the key failure of shared systems like this: they offer all of the disadvantages of mass transit with none of the advantages. The push should be to high-speed transit *via* bikes solving the “last mile” problem; walking is no longer an acceptable last mile solution (some super-lazy people will even circle a parking lot just so they don’t have to walk a few extra meters to the store).

          “While this concept may be a ways off from our current reality, my aim is to shift the center of the conversation by aiding in the visualization of our potential.”

          And that’s a good goal, so long as you keep in mind that most people are not going to approach it from a similarly high-minded perspective. They’re going to want practical benefits, and even if you manage to fool them for long enough to fund a pilot project, the dream won’t last long if it cannot live up to the level of potential you’ve got them expecting.

  9. Bubba Nicholson October 13, 2012 at 12:01 am -  Reply

    Hurray! Glad to see full aero fenders, finally. Now if we could just see them on regular bicycles, too.

    • Eric Birkhauser October 14, 2012 at 2:00 pm -  Reply

      Hey Bubba,

      Great to see you back in the forum. A very interesting idea, CFD analysis of a chassis approach on a standard bicycle geometry verses recumbent could be revealing. One that I will look forward to exploring, once I have resurrected this design based on all of this incredible feedback!

      Thanks,
      Eric

  10. Arnold October 13, 2012 at 9:16 am -  Reply

    Hi Eric,

    some thoughts on the design of the zipcycle. It appears to be very much a form over function design as others have noted as well, but it never hurts to look at problems from fresh and new angles.

    On the steering I would not worry to much about the arrow shaped handlebars as long as you do not make the point sharp. The arrow shaped bars are more common on recumbents. Even if you make it sharp it would still be safer than an airbag, as people will ride their bikes which much more care and attention :-)

    When I look at the design one thing that immediately struck me was the fact that you need to take the whole bike apart to replace a flat. Imagine doing that at 6 in the morning when it’s dark and raining. Flats never occur in the afternoon at 24 degree celcius for some or other strange reason. Secondly where am I going to leave any luggage on the bike?

    Perhaps the most important is that this design looks like a moving bottom bracket recumbent. These are notoriously difficult to master for beginners, so how do you envision these bikes in a sharing program? And thinking about it : isn’t the streamlined aero shape of these bikes particularly prone to damaging when people do crash it?

    I fully agree that bicycles and streamlined bicycles are a very viable alternative to motorized transport, however it needs bicycles that people want to use, can use and are practical to use. I doubt if you could get enough of a critical mass (needed for a sharing programm) on the basis of your current design, but do like the slick styling of the zipcycle.

    On speeds I do think you are right to state that the average speeds will increase. As a bicycle designer (recumbents actually) I’m also very interested in streamlining bikes and have visited Battle Mountain this year. It’s really an absurd idea to see bicycles going well over 70 mph and I do agree that designing a streamlined bike that can achieve speeds 25 and 35 mph is perfectly possible (in fact these already exist), however riders are mostly slowed down by lack of infrastructure even in the Netherlands.

    • Eric Birkhauser October 13, 2012 at 10:14 pm -  Reply

      Hello Arnold,

      Fantastic, you have very quickly and easily identified all of my deepest concerns with the design, thank you for your thoughtful and insightful assessment. Following is an explanation of my process through these open issues…

      It is a huge leap to shift from the tube frame paradigm to a monocoque chassis approach; one that brings a whole new set of challenges. I was waiting for the flat fixing issue to arise. Yes indeed, one side of the chassis front or back, depending on the repair would have to be removed. Currently each panel has a set of four quick release levers for access to the wheel. Indeed removing a quarter of the bicycle would be a challenge, which is why a combination of slime and heavier duty tires would go a long way in circumventing the issue. One plus of the chassis approach is that there are significant internal volumes to be utilized for storage. In one approach I am exploring, the seat could be pulled forward to open a compartment in the tailbox, which could provide moderate amount of storage space.

      Thank you for pointing out one of my biggest concerns with this design, the moving bottom bracket. Yes they are inherently less stable, which is why I have tried a number of rear drive approaches. With this strategy an internal chain cavity would extend from the crank to the rear wheel through a structurally constrained beam, thus weakening the beam. Which is resolvable, but the biggest challenge was allowing for pedal clearance over the pivoting front wheel fairing. This issue can be resolved by either reducing the front wheel size or allowing the front wheel to remain unfaired. Both approaches would work, but I am leery of tiny front wheels and or cranks obstructing turning radii. Earlier concepts had front wheel drives with fixed bottom brackets (most similar to the rapto-bike) shifted beyond the front wheel, but this strategy dramatically increased the side profile. So the moving bottom bracket allowed for a standard road bike drivetrain build and a coherent clarity in the design (I may be guilty for form over function here), but the jury is out on beginners and moving bottom brackets. My current thought is that if people can learn how to ride a bike, balancing on two wheels, then getting used to a moving bottom bracket would be like removing another set of training wheels, but I am truly undecided on the matter. With a working prototype, I hope to evaluate the issue more in depth, and it is very possible that a shift to a rear drive approach may be a necessity.

      On the durability front, a significant crash may necessitate the removal of several chassis panels, but smaller dings could either be popped out or simply filled and painted as most cosmetic repairs are done on automobiles. In the event of a major impact, a chassis could possibly absorb some of the impact, but we are not employing belts or roll cages, so I am uncertain of an overall benefit. Potentially the nose beyond the wheel support structure could be a replaceable bumper constructed of a more durable and impact absorbing material.

      Until the infrastructure exists, vehicles like this and others already in existence are a moot point. But the highway was not built for a model T either. There will always be a push and pull between the advancement of vehicular technology and the capacity and performance of infrastructure. The majority of my focus is on the challenges of infrastructure, in my everyday work and the book I am working on. But I have not been able to escape the intrigue of the challenge on the vehicular end as it is so informative to the infrastructure, such is my plight. Again thank you for your time and insight, it is GREATLY appreciated. I look forward any other thoughts or critique you may have in the future.

      • Arnold October 14, 2012 at 11:06 am -  Reply

        Hi Eric,
        as I said in the first lines of my response: by all means keep on trying new ideas and designs as that is the only stuff gets invented and done.

        With regards to the moving bottom bracket I would urge you to go and try one if you have the ability to do so. I have a fair amount of recumbent experience (build them, ride them and sometimes race them), however my first moving bottom bracket bike took me a couple of hours to sort of master going in a straight line. I may be guilty of having a slight favor for my own bikes here, but I would not take the moving bb frame into Amsterdam. The frame is still in my workshop…

        On the drivetrain side you may want to look at different drivetrains than conventional road drivetrains as I think you should not have derailleurs on bikes in a sharing program. Too much maintenance and prone to failures (not to mention expensive). There are some nice designs in the recumbent scene that solve many problems you mention. Mike Burrows (formerly Lotus and Giant) is making very innovative designs and Flevobike in the Netherlands have a bike with a completely closed drivetrain with a geared hub on the rear wheel.

        Damaging the bike would be a big concern I’d have if I were to manage the sharing program. When it’s easy to damage the bike quite extensively it makes for lots of repairs. This means cost out and the bikes are not available for the program. Also the team I have sponsored in Battle Mountain found that even slight imperfections on the body of the bike cause a massive increase in turbulence and therefore drag.

        Look foward to seeing your ideas develop.

        • Eric Birkhauser October 14, 2012 at 12:37 pm -  Reply

          Hello Arnold,

          Very strong points you make, I will give fixed bb configurations a deeper exploration. I am a big fan of Mike’s work at Flevobike, the green machine is a real breakthrough. I have looked at some internal driveshaft options in the past, but I was concerned with a loss of power, weight, and the complexity of the approach. But the sophistication of the green machine is an incredible proof of concept, disproving all of my concerns. The allure of an off the shelf conventional drivetrain is very attractive to me for prototyping purposes, but taken your advice I will reopen that chapter in the design. If I go that route, I will need some design and fabrication assistance from someone with experience in that department…

          Again a great point you make on the issues of damage and repairs. It will be difficult to ascertain the durability of a stamped aluminum foam backfilled chassis until one is made. However, this approach has been utilized for some time in architectural and structural panels, panels utilized for walkways and shear walls. So I think it may be possible to make something durable enough for share use, but I am certain a deeper assessment of material gauge and foam types to weight ratios will need to be undertaken. For the fist prototypes, I will have to make do with foam and carbon, until I can prove the concept is worth the tens even hundreds of thousands of dollars required for die making. But thank you for the tip on the aerodynamic impact of imperfections, very much appreciated.

          Again, I really appreciate your time and expertise. As I go back to the drawing board with this, your advise will inevitably be saving me countless hours, I am truly grateful for that. My very best to you.

          Eric

          • Eric Birkhauser October 14, 2012 at 1:46 pm -  Reply

            Just realized that the green machine is not a drive shaft approach, which makes it that much more brilliant!

            • Arnold October 14, 2012 at 2:25 pm - 

              Hi Eric,
              one other small correction Mike Burrows is not at Flevobike. Mike is making his own bikes. Johan Vrielink is at Flevobike makes other nice bikes.

  11. Eric Birkhauser October 14, 2012 at 5:35 pm -  Reply

    Oh thank you for that correction, would you like to share some of your work as well? Thanks!

    • Arnold October 14, 2012 at 7:26 pm -  Reply

      Hi Eric,
      RaptoBike is my brand. One of my models was featured here on Bicycledesign:
      http://bicycledesign.net/2010/02/raptobike-mid-racer-a-front-wheel-drive-recumbent/

      I have a second model which is fairly similar, but lower. Working on a tilting module for my own two bike to make them into tilting delta trikes and working with a group of people on a new tilting velomobile called Velotilt.

      • Eric Birkhauser October 14, 2012 at 9:34 pm -  Reply

        Arnold,

        Honestly, I must admit that I am completely flabbergasted, had I any idea I was going back and forth with one of my heroes, well I suppose I would not have changed my response, but nonetheless I am overwhelmed with gratitude for you time and thoughtful consideration. Your work and innovation has had an enormous impact on my exploration. I hope to continue to have your insight and expertise as my process advances. Again, my deepest thanks for your feedback,

        Eric

        • Eric Birkhauser October 17, 2012 at 1:22 pm -  Reply

          Arnold,

          The prospects of the Velotilt are quite impressive. The combination of your drivetrain and the leaning mechanism present a new clarity not yet present in velomobile design. I am curious to know if I could ask you a few questions off line, ebirkhauser@kgpds.com .

          Cheers,
          Eric

  12. Eric Birkhauser May 1, 2013 at 1:57 pm -  Reply

    Folks,

    Thank you so very much for all of your insight, it has been fundamental in the redesign. Please follow this link to my campaign to build a working prototype, http://www.indiegogo.com/projects/zipcycle .

    My Best,

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