May 2010
by larry

The Once and Future Microcar

The 1965 Peel P50 microcar.

I’ve been sharing with people my ambition to turn my Xtracycle “cargo bike” into a microcar. This has led me to ask what exactly is a microcar? And what would it take to give an Xtracycle the functionality of a microcar?

Microcar 101

It turns out microcars are not a new idea—they’ve been around since the dawn of the twentieth century. They are basically very small cars, usually between 150 and 1,000 pounds, powered by a 49cc to 500cc motorcycle-like engine or an electric motor, and often they are three-wheeled. They tend to be very cute and have become the objects of desire for many collectors and clubs. Various forces have caused microcars to wax and wane in popularity. For example they flourished after both World War I and World War II, perhaps as a way for people to economize. They also tend to flourish in places where their small size gives them tax, insurance, or drivers’ licensing advantages. Because of these economic forces, microcars are more popular in Europe and Japan than the U.S. For example in Austria and France they have a reputation for being the vehicle of last resort for people who lost their driver’s license for drunk driving. In some European countries, they became popular because taxes and insurance used to depend on engine displacement or  power. Modern Japanese microcars, called Kei cars, are designed to exploit local tax and insurance regulations, and in more rural areas are exempted from the requirement to certify that adequate parking is available for the vehicle.

I believe (and others believe) the time is right for the microcar to rise again, and I believe the bicycling community will have a hand in that transformation. There is a vacuum forming in our transportation system for a slow narrow vehicle that weighs between 100 and 1000 pounds. The car manufacturers don’t seem interested in coming down from their planet-wrenching upper end of the weight scale. It’s left up to the bike manufacturers to come up from the low end, to produce an intermediate-sized vehicle. My electric-assist “stoked” Xtracycle already has some of the specs of the smallest microcar, the Peel P50. The P50 weighed 130 pounds; my stoked Xtracycle with a canopy enclosure and other amenities will weigh about the same. The P50 has a 4.2 horsepower (3,131 watts) motor; my electric motor can put out 750 watts, which, along with some human power thrown in, might sometimes reach half that power on a good day. We’ve got the beginnings of a microcar here.

Furthermore, bicyclists can give birth to a new kind of vehicle because we are  unhindered by the constraints that the auto industry has. For example the side impact laws—necessary for vehicles that go highway speeds—make it technically impossible for the auto manufacturers to make a car that weighs less than 1000 pounds. Also the car industry is constrained by the limitations of mass production. Before the car industry can roll a microcar through it massive factories it must first ensure that there is a very large market for it. Bike shops, in contrast, only have to convince a few hundred people to buy one of their hand-crafted microcars which they can build from off-the-shelf parts. This situation is similar to the pre-mass production era when many small shops produced only a few hundred of their often eccentric cyclecars, the original microcars. Cyclecars were small inexpensive cars manufactured mainly between 1910 and the late 1920s. They were called cyclecars because they often incorporated motorcycle parts. They were very inexpensive for cars; the Buckboard cyclecar cost as low as $200 ($2,800 in 2010 dollars).

The auto industry must also overcome peoples’ expectations that all cars must be able to drive at highway speeds and highway distances. There is a movement among environmentally-minded manufacturers to create a new class of cars called Neighborhood Electric Vehicles, which weigh less than 3,000 pounds, typically have a range of 30 miles and have a top speed of 25 mph. But given what I know about American culture I don’t think this movement will succeed. People balk at the idea of a car that only goes 25mph, but a bike that goes that speed is cool.

So what is stopping a bike shop from making a microcar? Two things: the legal definition of a bicycle, and technical constraints. For an electric-assist bicycle to be legally considered a bicycle (rather than a motorcycle or car) it’s motor must be less than 750 watts, it must have functional pedals, it’s maximum speed must be less than 20mph, and it must have two or three wheels. This last constraint is important: if you give a vehicle four wheels it seems the full weight of automotive regulations falls upon it. There is some hope that these legal constraints will rise. For example I read recently that the motor limit in New York has been raised to 1,000 watts.

So is it technically possible to build a vehicle within those legal constraints that achieves the same functionality as a microcar? I believe it is. My Xtracycle cargo bike is almost there. Why hasn’t anyone done it before? Maybe because electric motor and battery technology wasn’t so well developed until now. Maybe the consumer base wasn’t there. Maybe the gas price, tax, insurance, and licensing forces weren’t in alignment. I sense that they are coming into alignment now.

What would it take to turn a cargo bike into a microcar?

What can a microcar do that a cargo bike can’t do? One big difference is speed. We can make a cargo bike faster by adding an electric motor, but we still have the 20mph legal limit. For me this is not a problem. Carrying capacity is more important than speed for me, and electric motors have an advantage over internal-combustion engines in this regard. For a given horsepower, electric vehicles such as my bike tend to be slow but with great carrying capacity, whereas internal-combustion-powered vehicles tend to be faster but unable to carry as great a load. For example my bike has a 400-pound carrying capacity and a maximum speed of 20mph, whereas the P50 described above probably can’t carry much more than one 200-pound person but it can carry them at 38mph. I would much prefer a microcar that can carry a lot rather than a microcar that is fast.

The next biggest functionality a microcar has that a cargo bike doesn’t have is a canopy. I’ve outlined my design criteria for an Xtracycle canopy in a previous post. Bicycles have a long history of incorporating canopies; bikes with a canopy are called velomobiles. However, again, velomobiles seem to be built for speed rather than cargo capacity. Another design direction that incorporates a canopy with a bike is the bicycle car, which typically means a pedal-powered vehicle with four wheels. A pedicab is a similar idea.

Other advantages of a microcar have to do with comfort and ease of use. Bicycling manufacturers are used to asking the bicyclist to conform to the bike.  Our microcar must instead incorporate some of the same human-centered design that makes Apple products such big hits. Bicycle manufacturers haven’t yet begun to explore the design opportunities that come from having an electric motor and a big honking battery on a bike. An obvious opportunity is to power the bike lights from the central battery rather than have separate batteries and switches for each light. Now that we have a canopy we can begin to think about how to keep passengers warm. Another  set of design opportunities comes from the cyclist no longer having to be thrifty with power. For example I took the toe clips off of my Xtracycle since any minor advantage they offer is overwhelmed by what the motor can do. And it now becomes possible to consider a shaft drive instead of a chain drive, since its minor inefficiency pales in comparison with the advantage of not having a greasy chain.

Here are some general microcar design criteria with some ideas about how they might be satisfied. Got ideas of your own? Please comment and I’ll add them to this post.

My microcar can carry the driver and one passenger comfortably. The biggest design choice here seems to be having people sit side-by-side or front-back. I like front-back so that the vehicle is narrow. This is important so that the vehicle can ride on the shoulder since it is slow. But a side-to-side design, particularly a recumbent trike, could be explored.

My microcar protects the occupants from rain, wind and cold. The traditional microcar uses sheet metal or plastic. I think cloth is the best material since it is lightweight. A cloth cover can be changed to fit the season. The winter cover could be insulated. And it may be possible to integrate electronics into the cloth, such as tail lights and headlights.

My microcar is easy to maintain.

My microcar weighs between 100 and 1000 pounds.

My microcar is powered by a 500 to 1,000 watt motor. Now that New York will have a 1,000-watt maximum motor size, I am imagining an Xtra-cycle microcar that has a tricycle attachment replacing its rear wheels. And each wheel of this trike attachment has a 500-watt electric motor hub. Now we’re talking.

My microcar has a top speed of 20mph.

My microcar costs less than $5000.

My microcar has a 400 pound total cargo and occupant capacity.

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  • http://Website pimpbot

    Neat idea! There was a time when I chuckled at motorized bicycles. I thought, ‘just pedal, you lazy (deleted)!’

    Now I see it as an alternative to a car. There are more errands you can run, with less effort.

    What about crazy light cars? VW recently had a three wheel prototype that got 100 MPG+ and a 0-60 in 5 seconds or something stupid fast. IIRC, I read it would fall under motorcycle registration because of the trike layout.

    Maybe think along the lines of a 3 wheel pedal car, but with assist. Recumbent seated would be best for handling. With three wheels, weight is less of an issue because of tipping. Sealed Lead Acid batteries are pretty cheap for watt/hr/$$ factor, but heaviest for watt/hr/mass. Somebody has to have a go-cart style three wheel frame out there that can be rigged for pedaling. Some Avid BB7s with big rotors can easily be rigged to a hand brake on the steering wheel/bar, even doubled up for the front brakes.

    Okay, you got me thinking…. now i just have to learn to weld. :)

  • http://clevercycles.com/ todd

    i’m surprised you make no mention of assisted velomobiles (http://en.wikipedia.org/wiki/Velomobile), which your stoked, faired xtracycle would seem to be more than a motor-only microcar.

    alas the only production velomobile with capacity for a passenger i’ve seen is the ~30K$ Twike.

    i know that a stoked velomobile with 200-mile assisted day range and substantial cargo capacity is imminently feasible.

    • admin

      The velomobiles seem to be more oriented toward speed than cargo capacity–if you have to put a parachute on it to get downhill that’s getting beyond what I had in mind. It seems the purpose of the velomobile’s covering is more for aerodynamics than protection from the weather. But again it’s a matter of semantics: if you put a canopy on an Xtracycle, it’s like a velomobile. If you put a motor and a canopy on it, it’s like a microcar. Unless it’s a velomobile with a motor.

  • http://Website DK Stangeland

    I thought of this when I read your post:


    A little different but still cool and forward thinking.

  • http://Website Adam B

    I’m glad to see more and more people thinking along the same lines. Microcar definitely seems like the way to go, eventually.

    You seem really concerned about these goofy laws. Three wheels vs. four, the arbitrary wattage and speed limits…
    And yet you have no quandaries at all about challenging the cultural and infrastructural status quo.

    I say build the best mousetrap, and people will change the laws rather than allow the spectacle of an obviously superior product being banned from roadways.

    To that end, I’d say safety is key. Rollbars and airbags.

    I think in the end, the ideal ends up looking like a cross between
    and a transcontinental solar racing cars,
    and a recumbent tandem like Kurt Ritchie’s Beast: http://www.flickr.com/photos/92904566@N00/799316939/

    I still think human power should provide a big portion of the power. 250W isn’t out of the question, and a set up that engages more muscles (like rowing, as used in the humancar) could well obtain much more. With the aero advantages of fairings and reduced frontal cross-section, I think you could easily get well over 30 mph on flats with no motor assist, then hit the 1000 W motor on uphills to keep the speed close to a constant level of 30 mph.

    I’m thinking lots of carbon fiber, but that can be expensive for homebuilders… I don’t know how one could have decent crash protection while keeping weight down, without synthetics.

    Another alternative is to introduce even more technology into current cars, so they drive themselves and communicate with each other or some central grid. They could draft off each other, reduce crashes, and avoid congestion. Not the same human-centered experience, and in fact even more alienating, but at least it cuts down on environmental impact and fatalities, so maybe we can move both directions at once?

    • admin

      I’d say limiting speed is the key, and safety will follow from that. You don’t need rollbars and airbags if you are going less than 25mph. One of the nice things about human-powered vehicles is that it’s hard for a human to propel themselves at more than 25mph. That low speed makes it possible for that human to relax and be courteous in transit. Once that human is enclosed in a car body they are cut off from their fellow travelers and rudeness comes more easily. And when traveling at speeds higher than 25mph they enter an inertial frame having physics that they were not designed to handle, either physiologically (requiring crash protections) or psychologically (such as reduced reaction time).

      That said, it’s very fun to go fast! I recently put a large hub motor on a small bike, loaded it with four small car batteries, and took off down a dirt path. A grin involuntarily formed on my face. After all my ranting against speed here I was enjoying it.

      I agree with you about trying new technology. Our current most visible traffic control technology is the traffic light. I have always felt that traffic lights benefited motorists at the expense of bicyclists and pedestrians. I was pleased to find this idea confirmed in the book Traffic: The Dawn of the Motor Age in the American City. Another point this book makes about traffic lights is that they were never really scientifically confirmed to be the best solution to the problem of congestion. And in fact people have recently shown that in some contexts traffic flow actually improves when you take out traffic lights. Without traffic lights motorists are forced to pay attention to each other, and negotiate with each other, as pedestrians do. I think we can remove traffic lights and use other methods to control traffic based on new technology such as cell phone signals. Within a city, a radio signal can enforce a 25mph speed limit. Because they are going about the same speed, eBikes and NEV automobiles can ride together rather than get in each others’ way. (In this futuristic scenario gasoline-powered vehicles have been phased out :-) ) However, in the country the speed limit signal can be increased to 45mph. If two cars are approaching an intersection at the same time, the signal will require them both to slow down so that they can negotiate the crossing. I agree this seems a bit big-brotherish, but my point is that what we have now doesn’t work for us slow moving vehicles. If we as a society want to embrace slow moving vehicles we need to change our traffic control methods. We have the technology, we just don’t have anyone thinking about it creatively yet.