The design of the Nimbus mini-EV and why it's different from other cars

Nimbus mini-car has 3 wheels and fits in the space of a motorcycle, with most of the advantages of a car

Recently I posted about my involvement in Nimbus, a new mini-car that is in development. Minimobility (my own term) consists of cars that are much smaller than the typical 5 seater sedan, typically seating only 1 or 2 and being much lighter. Many are narrower and easier to park. As a result they are also much more energy efficient and cheaper to make.

Mini-cars don't have a great history, at least in the USA. Most have not sold very well. You will find them more often in Europe and Asia, and in fact in some countries small vehicles (including scooters, motorcycles and tuk-tuks) are the most common type of vehicle.

You can see a video of me driving it in my LinkedIn post on the car. Also see some YouTube reviews below.

Mini-cars are interesting because they need much less road space and parking space. Over 80% of car trips are alone and within town, but we make them in 5-seater SUVs more than anything else. A great deal of energy use, pollution and road congestion can be blamed on this fact. If we could get a large fraction of trips to mini-cars, it would do a lot of good -- and be good for those in the mini-cars as well.

One key reason you don't see many mini-cars is that car shoppers usually look for a car that meets all their needs. Yes, most of their trips are alone and would be great in a mini-car, but a few involve groups of people, or large cargo, or long trips out into the country. We buy a car that can do all that but use its abilities rarely.

One way to fix this is with robotaxis. With a robotaxi, you can summon the right vehicle for the trip. You don't ask what car you need for your life, you ask what car you need right now. A robotaxi user would take 80% of their trips in mini-cars, and only sometimes use an SUV or pickup-truck or minivan. They would save money and improve the city and the planet. There's little not to love, other than the fact we don't have robotaxis, and especially mini-taxis, today. You can make a luxury mini-car so even the wealthy pick this route. If mini-cars get incentives like carpool lane access they become the choice of even the richest people, in spite of being the cheapest cars.

Here are some of the design factors of the Nimbus that I believe can make it be the best city car, and a good purchase for a large number of drivers, though not for everybody. I am an advisor and stockholder.

Small footprint -- 34 inches wide

Many asked about the design of the Nimbus compared to other mini-cars of the past, both production ones and prototypes. The Nimbus has designed to fit in a very small footprint but still offer most of the desired features of the car. At 91" by 34", The footprint is small enough that it can park in motorcycle spots, park perpendicular to the curb when regular cars park parallel, and even ride between lanes in states like California that allow that, as motorcycles can.

For a car to be that narrow, and still be stable, you might fill the bottom with lead, like the Tango, or try to put a gyroscope on board like the prototype Lit C-1. The City Transformer has axles that extend out to make the "stance" (the space between the front wheels) wide when driving, and narrow when parking. Most other mini-cars don't have a narrow stance -- the wheels are on extended axles to support the vehicle in turns. The Aptera, a 3-wheeled car which failed a decade ago but is coming back, actually is wider than a conventional car.

The Nimbus solves this by leaning, as all motorcycles do. It is a 3-wheeled vehicle with 2 wheels up front and one in the back. By being 3 wheeled, it need only comply with the rules for motorcycles, which is a must for a startup. Making a car that complies with the 4-wheel Federal Motor Vehicle Safety Standard is a hugely expensive process mostly for big companies.

The drive-by-wire system leans the car into turns, so it's stable while being narrow.

On a trike you can have two wheels in the front or back. In the front makes you much more stable. There is another leaning vehicle called the Carver which is similar to the Nimbus but has only one wheel up front. (That makes steering easier but is otherwise not worth it.) It is also 9.5' long, which will not fit perpendicular in some parking spaces.

So the core "why" of the Nimbus is to have that small footprint. That's good in traffic but the big plus is in parking, either at destinations or in your own garage. In cities, the thing people dislike most about car driving is parking. You either pay a lot for it or waste a lot of time finding it. A car with the footprint of the Nimbus can find parking almost anywhere, often free or cheap. A larger footprint just can't do this. While short cars like the Smart ForTwo are certainly easier to find parking for, the size of the Nimbus is at a whole new level.

That's also true for people who have small garages, what are often called one-car garages. They could often fit a Nimbus in addition to a regular car. Two car garages might fit two cars and a Nimbus. For people with no garage it may still fit in an abbreviated driveway, or may just find it easy to park on the street. All those small gaps between driveways that can never fit regular cars are open to it.

That's one of the primary markets for such people. It's an ideal second car in the "city car" class. Households will switch from 2 full sized cars to 1 car and one mini-car. They still will have a car that can do all the things in their life, including that ski trip with 4 friends, but most families don't need two ski trips at once.

Other than seating only 2 and not going on highways (in the base version) it's a car. It drives like a car (it does the leaning, not you) and is enclosed from the rain like a car. It's got a roll cage and steering wheel and seat-belts and an airbag. It also has forward collision warning. No, it's not going to be as safe in a crash as a Toyota Land Cruiser, but it's going to be a lot better than a motorcycle, in spite of having most of the advantages of a motorcycle.

Almost all recent mini-cars are EVs, and so they gain the many advantages of EVs. Because mini-cars are small and light, they use much less energy. That means they can have smaller batteries, and recharging them after a day's driving takes less energy and less time. In fact, the Nimbus doesn't have DC fast charging because it doesn't need it -- the regular Level 2 charger that is considered very slow for a regular EV will refill the batteries in about 35 minutes after an average day of driving and from 0 to 100 (which never actually happens) in just over an hour.

Being small means efficient. It goes 91 miles on a 9kwh battery. (Compare to a Tesla that goes 260 miles on a 62kwh battery.) This is more efficient than any car, any gas scooter, or any transit system in the world! Only an electric scooter does better.

More videos:

Modular hand-swappable batteries

But the other special design feature of the Nimbus is to use swappable batteries. While in the future this can mean using battery swap stations (it uses a simple modular battery you can swap by hand) like Gogoro in Taiwan, the purpose today is to let you charge the vehicle in your apartment. It turns out for many people who want to buy EVs, the inability to charge at home is a big barrier. Renters and people who live in houses without parking can't put in charging -- though all the Nimbus needs is a standard 120v plug which is built into the car. Instead, they can pick up two of the battery modules, which have a handle, and bring them inside for a charge. Suddenly millions more people can have an EV they charge at home. Charging at home, which happens while you sleep, is by far the best way to charge an EV, though this does involve a little hauling.

Another benefit of swap is that an owner could buy extra batteries and put them in the cargo area, allowing extra range if needed. Though the 90 mile range is enough for any day in a city car.

Initially Nimbus doesn't offer the other kind of swap, namely the use of swap stations for an instant recharge. That can come in time, though.

Drive by wire

Nimbus controls go through the computer. It defines the handling, and manages the leaning so you get car-like driving feel on a narrow vehicle. You can also adjust the driving feel and make it more motorcycle-like. This assures the vehicle is stable no matter what you do.

A universal reaction on test drives is that it's a lot of fun to drive, as well as fairly easy. You get the enjoyment of a motorcycle without the risk and other downsides.


This is a city car. The base version doesn't do the highway at all. The faster version will, but does not have the range for road trips or ski vacations. The back seat is somewhat cramped, but fine for many people. It can also hold cargo (as can a rack on the back) but you obviously don't have the cargo capacity of a full sized vehicle. Of course, if you have more than 2 people, it's not going to do the job. As noted, it won't be as safe in a crash as a large car, but it's much safer than a scooter, motorcycle or bicycle. Some people are surprised by how it leans at first, but tests show people get used to it very quickly.

In summary:

  • Narrow footprint for trivial parking, easy movement on the street
  • Leaning so it can take corners with a narrow width (stance) between the wheels
  • Small and light means low cost ($10K) and super-efficient (100 wh/mile), with more range (91 miles) on less battery (9kwh)
  • Hand-removable battery modules allow recharge in your apartment
  • Drive by wire so drives like a car, easy and fun.
  • Car functions -- seat, roll cage, airbag, ADAS collision warning, enclosed from elements, heating/AC, seatbelts, back seat

Contrast with others

There are a number of other players. Only a couple match the Nimbus (at higher prices) though all are interesting. In particular only a handful lean and can have that footprint that goes in a motorcycle parking spot. Some of these are from the past and discontinued, or were concepts that never got made in volume, and some are prototypes with plans for the future.

  • Aptera -- efficient side-by-side 3 wheeler, but 81" wide and 172" long -- not really "mini" -- and $26K to $50K in cost
  • Carver -- very similar but solo front wheel which is less stable, and longer
  • Smart ForTwo -- 65-75" wide, 106" long, just a short traditional car
  • Corbin Sparrow -- wide stance trike, doesn't lean
  • Toyota iRoad -- fairly similar, concept car that never went into production
  • Reliant Robin -- solo front wheel, notoriously unstable, though 56" wide
  • Arcimoto FUV -- wider stance, more expensive, 61" wide
  • Electromechanica Solo -- 63" wide, $19,000
  • Lit C-1 -- leans, two wheels, gyroscopic stability, still in development after 10 years
  • BMW Isetta -- side by side seats, so wider and 4 wheels.
  • Renault Twizzy -- four wheels, 49" wide, does not lean. Did go into production in Europe
  • NEVs -- golf cart base, limited to 25mph
  • Quadro 4-wheeled tilting motorcycles and many other 3 and 4-wheeled tilters exist in Europe. They are motorcycles, not enclosed, and ridden straddled, as a motorcycle.
  • Tango EV -- 4 wheeled, narrow, extremely heavy and expensive. Only a dozen made
  • Velomobiles -- enclosed bicycles, some with electric assist, which you pedal. 3-4 wheels
  • City Transformer -- 4 wheels, narrow, wheels extend out when moving for stability. Also in prototype stage

Building it

Nimbus has made prototypes but is not yet in production. It's doing fund-raising to get to the product stage at present. If you are a qualified investor interested in bringing out this future of small, efficient, green transport, get in touch. A combination of many factors, including the recent soaring rise of EVs in general, the ability to computerize the driving experience, lighter, lower-cost batteries and components and a rise in demand for small, low cost and efficient transport by Millenials all point to the dawn of a new era.

Car or Motorcycle?

Some people look at this as a car with the advantages of a motorcycle. Others see it as like a motorcycle with the advantages of a car (or without the downsides of the motorcycle.) It is indeed somewhere in between. Motorcycles are fast, fun and take very little room, but they are disturbingly unsafe and unpleasant in bad weather. There is obviously a market for both cars and motorcycles, with the car market being the larger one. People are convinced cars have to carry 5 people though they almost never do, so the question will be whether people can get past that in order to win on parking and road space and cost. The energy advantages of this are off-the charts. 100 wh/mile is incredibly good. The New York MTA subway, the most efficient transit in the USA, is about 166 watt/hours per passenger-mile. This thing can compare with the more efficient Tokyo Subway. If people want a low carbon footprint, this is a winner. Of course, people say they want a low carbon footprint, but many of them don't really mean it, so it has to also win on other factors. ~


Bugatti Rimac is involved with the udelv Transporter.

Ask Rimac for input.

Well, Mate is known for super high performance cars and the Transporter is a large size vehicle, so what's the particular connection here? I mean, he's a great guy and he and his team know fantastic things about EV performance but in a different part of the market.

UK trade paper sit-down with mighty Materman quite the while back in the Greyp Bike founding days captures impromptu snippets on e-trikes and personal micro transport. Will look.

The price was lower than I expected. I wonder if they’ll be able to ship at that price or not, though. (Also just noticed the base price doesn’t include A/C. That’s a big minus.) Hand-swappable batteries is intriguing. 5.4 hour charge time from a household outlet is acceptable. Do you know if any charging equipment is needed to charge the batteries outside the vehicle? Would be nice to be able to charge outside the home without bringing any extra equipment. Means your range can effectively go from 90 miles round trip to 90 miles one way. Could go cross-country on 90 mile legs (without much planning) if you’re into that…

They should say how much A/C costs. I wonder how badly that’ll kill the range. It’s hard to imagine commuting on hot days without it. If it had A/C at that price I might have already put down my deposit and started working on getting my motorcycle enforcement.

Clearly you can't have everything at $10K. There are places like California where lack of AC is acceptable. Of course, put down the window and you have the same AC all the motorcycles have :-). Don't have any estimate at present for what AC is likely to add to the cost, but it should not be too bad, it's a fairly small space to cool.

Yes, customers get a dock to put in their house in which to place the batteries. Right now it's not very portable, but I expect a portable one is certainly possible. However, it's explicitly not a cross country car, and that's for the future. However, at non-urban destinations and even most urban ones, there is a retractable standard 120v plug in the charging area. Bring along a heavy duty extension cord and you can plug the vehicle in if you can find a dedicated plug. That will handle a lot of locations, though not every one.

You don't need a motorcycle licence in many states, but there are states where it is needed.

I don't have any specs on the AC need, but this is such a small space that I could see decently low values. I know the Tesla AC which is much larger can draw up to 2kw initially, but has been measured to average around 500w or less once the vehicle is cooled. So each hour of Tesla level AC would presumably eat about 5 miles of range. But this small space should need less than the Tesla does. More if it's killer hot, and no doubt a few miles eaten up cooling down a car that was sitting in the sun.

Podbike Frikar

This is a velomobile

Twike GmbH with Vitesco Technologies etrain

with AC, I am almost ready to sign up. highway travel is important as 90% of my trips about 30-40 min highway travel away. I can work around that by back roads and a 30% increase in travel time. I'd have to live with the vehicle for a few months in New England winter and our now blistering summers to see how well it works.

I would like to see a single wheel trailer to carry heaver loads. food shopping for our family is a 2 person, 6-7 heavy bag trip every 10ish days. A trailer is a good way to expand cargo carrying capacity when needed. I would also use a trailer when car camping at nearby state parks or dragging my observing kit out to a dark sky site.

I would love to be an ambassador showing that a "city" car can free you from a city life. like putting skis on the front wheels, chains on the back and take the nimbus wintertime back roading?

wrt renting robo cars, I worry about the cost. When I've bought vehicles, I take them to 200K+ miles. they get really cheap to operate above 80K miles. with a rented robo car, I fear I'll be paying new car per mile prices no matter how much I use the car.

second issue is availability of larger capacity vehicles. Had to help a friend with an emergency move this weekend. not a van or truck to be found withing 50 miles. why? semester move in weekend for local colleges. I don't think robo vehicles can handle peak loads any better. Also, hope they have really good maps so they don't get storrowed. see:

third is having cell service at a pickup site. Many trail heads have no cell service. you can be dropped off but there is no way to order a ride back.

the meta question behind these hazard example questions is why should we handover more of our lives to big companies, organizations that only care about extracting money from us. look at the US Hedge funded medical industry to see how well that is working out. Look up hedge fund managed elder care facility and how they extract every last dollar from employees, patient facilities and medicare to payoff share holders. do you think the robocar industry will be any different? hasn't been with hedge fund involvement in rail, housing, and pharma.

I expect you will be able to order older robotaxis for less, though most likely they will be refreshing the interior to keep the quality up. Tesla plans to do their service with off-lease cars, so always a bit old.

No reason robotaxis can't handle peak day -- after all today look how many vehicles we have sitting around just so we can do peak day. It's going to be cheaper for the robotaxis. Services will know that if you turn customers away and strand them they will not use you for car replacement.

The new T-mobile/starlink service will let you order a ride back in places with no cell service. Or of course you could book a time. Robots don't mind sitting around waiting for an hour, they are not like people. So order one for the soonest you could get to the trail and it will wait for you all day if you want, for perhaps 50 cents/hour.

past is littered

Peugeot PHEV tilting scooter
Persu Hybrid
Peugeot EU-LIVE project

2021 demos


Was fairly similar (though had gasoline engine) but it seems to have been just a concept. The Persu was licenced from the Carver design. The Sondors is a wide stance (side by side in fact) vehicle.

I have not been tracking the Imperium. There are lots of trikes in China. This one is a single forward wheel.

Energy Will Reach 20% Of Disposable Income in Europe

zerohedge dot com/commodities/europes-nightmare-scenario-comes-true-energy-bills-rise-eu2-trillion-will-reach-20

City Transformer CT-1 two-seater

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