More about my Hammer Truck

I recently received the following email from a reader:

I was researching cargo bikes and just kept seeing your blog pop up. I am very interested in doing a similar set up as yours.  I also was interested in elMundo initially.  A sidenote on the weight of the elMundo: they are now selling it with the electric components already attached and the shipping weight of the bike and box was 100 lbs. which seemed like a lot.

My question is pretty simple. I haven’t tested a Rans Hammer Truck in person since this is just the planning phase.  I read the height of the bike had a 31- 38 inseam. I am 5’5″.  I wondered about the comfort of the frame.  And if your wife was shorter than you and found the Hammer Truck comfortable… ?  Also just to pick your brain (and thank you very much in advance)  how did you like the Hammer Truck handling without the electric assist? You mentioned you test rode it for a day…

My plans are just like yours, I want to use it to take my 2 kids to school and errands and fun – reduce car use in general.  The kids are 6 and 4 and the bike trailer is just not cutting it these days.

Oh yeah! one more question. I read your post worrying about brakes.  Currently with the bike trailer I often hop off and just walk up the hills.  My question is, is a cargo bike easy to walk with when it’s carrying about 50- 60 lbs.?  Or very tippy? 

Thanks for the blog. I am surprised the Yuba people haven’t offered to let you test drive their bike. Surfing I ran across another cargo biker’s blog who actually bumped into the founder/owner while on a bike tour in Europe and had a very good impression of him and a good talk with him.

Thanks again. Happy biking! I am so happy I stumbled across your blog.

Best,
Jessamin

Thank you, Jessamin.  Your email reminded me that there are still a few things I can say about the Hammer Truck.  For many months, I have felt a bit uncomfortable about my bike’s relatively high cost, and I have been researching less expensive bikes that might appeal to a broader market.  That has been an interesting project, and I intend to continue doing it for a while.  But I don’t own these bikes or ride them on a daily basis.  My real expertise is my particular bike, and answering your questions gives me an opportunity to return to familiar territory.

To answer your question about bike height, my wife rides the Hammer Truck very comfortably.  At 5’4″, she is a little shorter than you.  As you can see in this photo, the seat stem for the Hammer Truck is angled at approximately 45 degrees.  When you lower the seat an inch, you also get an inch closer to the handle bars.  This seems to scale well for most body types.

Hammer Truck seat stem

While you’re looking at the seat, I will also mention that the inclination of the seat is adjustable.  When I first started riding the Hammer Truck, I had the seat almost parallel to the ground, like a normal bike.  However, the Rans web site shows their seats tipped forward, so I tried it.  It feels a bit like standing and leaning against a wall.  Tipping the seat puts a little more weight on your feet, and that’s what you want when you’re riding.  The slight curve of the seat back allows you to dig in for a little extra leverage when you need it.  These are all helpful when you really need to crank!

The Hammer Truck worked fine without the motor.  If we still lived in Denmark where it’s notoriously flat, I wouldn’t have needed the electric assistance.  I’ve spent so much time on this blog bemoaning the hills in our neighborhood, I decided I really needed to show you what I mean.  Yesterday afternoon, I put my 9-year old son behind the camera, and he took a video of me pushing my daughter up the hill, riding without assistance, and riding with the motor providing maximum assistance.

As you will see, this hill is a monster.  When I write about heating issues with my motor and brakes, you need to understand that I’m pushing both to a limit that most people won’t encounter.  Despite my occasional complaints, it’s pretty amazing that this bike can handle this kind of challenge.  (Note: the scraping noises heard in the video aren’t the bike — my son was balancing the camera on a mailbox to keep it level, and scraping as he pivoted the camera.)

You can also see from the video, pushing the bike uphill is possible, but not fun.  The side bars that carry loads so well are approximately where you want to put your feet, so you have to lean over a little.  It might be hard to see in the video because I’m already leaning against the hill so much.  It’s not as tippy as I thought as long as both hands are on the handlebar.  It would be almost impossible to do one-handed.

You might notice my slightly hunched posture when I’m riding in this video.  With the Hammer Truck, you generate power by pulling back on the handlebars, engaging the same muscles you would for rowing.  In my case, I can produce more cranking force this way than I would standing on my pedals on a traditional bike.  It’s more of a full-body workout, especially when I turn the motor off.  However, this might not be a good idea for people with fragile knees.

Speaking of cargo bikes on hills, this is probably a good place to mention one of my favorite web pages: Cargo Weight Calculator.  The calculator which gives you a rough idea about how much weight you can expect to haul up hills of varying steepness.  Another page on the same site shows you how to measure the grade of a hill.  Every time I turn off my motor and I’m reminded how hard it is to climb a hill with a load, I return to this web site, punch in the numbers, and I’m assured that there are real, mathematical reasons why it’s difficult.  It’s not because my motor is making me lazy.  🙂

Sometimes I get distracted by all the details of this project: the specifications, the prices, the compromises.  My blog is kind of heavy on that sort of thing.  I occasionally need to remember that there is an emotional and even inspirational side to cargo biking, and my favorite blend of practicality and inspiration comes from the Couch Potato to Full-Time Cyclist blog.  If you haven’t seen it, check it out — it’s really a great counterpoint to what you read here.

Solar Xpedition Day 2

I was frustrated about having to repair a flat tire every hour or so and I was concerned that I might run out of patches. I needed to get to a bike shop soon. There was a Walmart 12 miles away in Rome. Could I make it? Long story short I made it. I bought three inner tubes, two patch kits, a floor pump, a tire, and a file in case I needed to convert my presta rim to schrader.

Any kook can slap a solar panel on a bicycle and call it a solar bike. How am I any different? Mainly in my lack of ambition. I don’t want to create a ground-breaking product that will rocket me into the halls of fame. I just want to charge my battery however much I can within my budget. I just want to do the experiment to find out if adding a solar panel to my bike is worth the effort and expense. And if it is, I want to post instructions on my blog here so others can follow in my footsteps.

People see my bike and they expect that the solar panels power the bike completely. The reality of course is that the solar panels are an accessory to an accessory. First of all the electric assist is an accessory to you the bicyclist who is pedaling. Secondly the solar panels are an accessory to the electric assist. The solar panels supplement the electric assist’s batteries in those few instances where you can’t get to a power outlet. So despite the panels’ physical prominence on my bike and in our imaginations, currently they have only a minor role in actually making the bike go forward. Not insignificant, but minor.

What would it take to give the panels a major role? At least a four-fold increase in power. Currently the panels produce about 25 Wh per hour. 100 Wh per hour would be very useful for a long trip since it takes me about an hour to use up 100 Wh. That means I could accumulate energy about as fast as I use it. I could go indefinitely (on a sunny day). I think it’s entirely possible to get a four-fold increase with existing technology. Just adding more panels is a start (perhaps as a canopy over the driver). And it may be possible to make the panels more efficient by adding a charge controller with sophisticated electronics (such as Power Point Tracking).

Bicyclists out there may be wondering “If the power you get from the solar panel is so small, why not just take all that crap off your bike and pedal the damn thing?” This is a very good question that has been nagging at me throughout the ordeals of this trip. I have to keep in mind that this is just a beginning. The point is not to just reach my destination here and now. The point is to pioneer a new type of vehicle. It’s not a solar car–it has pedals so that its human can supplement its power if necessary. Is it a bike? Whatever it is, it is a vehicle that is so lightweight, narrow and slow that even the meager power of the sun can power it.


Adirondack Gateway Campgrounds = heaven

catching photons in Hinckley State Forest

My Solar Bicycle

I am anticipating peoples’ reactions:

“Why do you have solar panels on your bicycle?”

“What do you do when it rains?”

“Can the solar panel drive the electric motor directly?”

“Did you make it yourself?”

“What the…”

Allow me to explain. My vehicle of choice is a “stoked Xtracycle”. (For those of you not “in the know”, an Xtracycle is a type of cargo bike that has an extra long frame. And “stoked” means that my bike has a Stokemonkey electric motor that helps me out on the hills.) In general this summer I’ve been biking 10 to 20 miles a day and then recharging my battery overnight by simply plugging it into an outlet. However, next week I’m going on a 3-day 240-mile camping trip through the Adirondacks where I might not have access to an outlet. The solar panels will help extend the range of my bicycle. So to answer your questions:

“Why do you have solar panels on your bicycle?”

I use them to extend the range of my electric cargo bike for long trips (plus they were fun to make). I will carry two batteries on my trip, each giving my bike a range of 20 to 40 miles. On a sunny day the solar panels can recharge one of the batteries while I am riding, adding an additional 20 to 40 miles for a total range of 60 to 120 miles a day. I anticipate some hills and I’ll be carrying a load, so a 60-mile range is probably more accurate. I may need to pedal the last few miles on some days.

“What do you do when it’s cloudy or it rains?”

I plan to stay in a hotel some of the time and recharge my batteries there.

“Can the solar panel drive the electric motor directly?”

Not really. The solar panels don’t produce enough electricity instantaneously. For example the solar panels only produce about 40 watts of power at a given moment, whereas my bicycle needs about 400 watts of power to go up a hill. The main purpose of the solar panels is to charge the battery over time.  Since charging happens slowly, 40 watts is enough to charge the battery. It takes roughly 10 hours of charging to store one to two hours’ worth of electrified riding time in the battery. And one to two hours of riding translates into 15 to 30 miles.

“Did you make it yourself?”

I already had the stoked Xtracycle, which is described on my About This Bike page. As you can read there, an electric cargo bike can be had for $1000 to $3500. And I had already constructed the canopy frame for a previous project, the Bike Wagon Canopy ($150). I found the canopy was somewhat wobbly with the weight of the solar panels so I had to strengthen it with guy wires. It remained for me to add the solar panels and the electronics. I used maritime-grade solar panels that were designed to keep sailboat starter batteries charged up, so they are extra-sturdy and consequently somewhat expensive. I’ve since seen panels with almost twice the power at 3/4 the price. Cost of panels: $900 to $1200. I am using three 12-volt panels in series to produce the 36 volts required by my battery. I spent a lot of time researching what sorts of electronics I would need between the panels and the battery, and finally concluded that I can just plug the panels into the battery directly. (I plan to write more about this in a later post.)

Total cost for a solar bicycle: $2050 to $4850. Not bad for a vehicle that can get you both out of the car and off the grid.

More of My Big Manly Cargo Bike Loads

Guess what is in this 50-pound monster pannier.
Guess what is in this 50-pound monster pannier.

Us cargo bikers get a thrill out of telling everyone what big loads we can carry (see Their Carrying Capacity and My Carrying Capacity). I am no exception. Here are some of my latest big loads.

Cargo bike economics: maintenance

Today I took my bike for its first checkup after 7 months and over 500 miles of hill-chewing.  As you may recall, I have done no maintenance on this bike other than one application of chain lubricant.  Since I rely on it to provide safe transportation for my family, I wanted to ensure that no latent problems were developing.

For the diagnosis, I went to one of Seattle’s pricier bike shops.  I deliberately chose a different shop than the one that built my bike, because I wanted a second opinion — especially on those mission-critical brakes.  The owner of this shop is a big fan of the Big Dummy/Stoke Monkey bike, and I thought it would be enlightening to talk with someone who is somewhat skeptical of my bike.  He has a reputation for pulling no punches, so I prepared myself for some rough sledding.

But actually, things went quite well.  The owner found several occasions to point out advantages of the Stoke Monkey, but these were arguments that I’ve written about previously.  He complained that the BionX hub motor makes it harder to adjust the rear disc brake calipers, because the hub blocks easy access to the dial that positions the brake pads.  He charged me an extra $10 for the additional effort required.

The total bill was $75 for labor.  He adjusted and lubed my derailleur to recover my lost gears, cleaned and tuned the brakes, and lubricated various cables.  I paid another $25 to upgrade the front brake cable for better responsiveness, but that wasn’t critical.  Using the $75 figure for essential maintenance, I calculate a cost of about 15 cents per mile.  On the one hand, this figure is probably high due to the difficult geography this bike has to tackle.  On the other hand, it’s probably too low on an annualized basis, because I didn’t have to replace any parts this time.  In another 6 months, I may have to replace at least one of the disc brake rotors and possibly the pads, but that shouldn’t cost more than $50.  As I suspected, the regenerative braking of the BionX motor seems to be extending the life of my brake components.  What isn’t clear is how often other components will need to be replaced, and how much that will cost.  Although it will be pretty cheap compared to repairs/maintenance of a car, the number of bike miles will also be less, so it remains to be seen which is cheaper on a per-mile basis.

Just to be complete, the electricity to help propel me during this time period averaged about 1/2 cent per mile.  Hardly worth mentioning compared to the maintenance.

One sweet moment occurred while I was paying my bill: a customer was admiring my bike and asking questions about it.  He was initially attracted by those huge Xtracycle-incompatible pannier bags.  He was really intrigued when I told him the bike was assisted by a quiet (and virtually invisible) electric motor.  He was standing less than a yard away from the owner’s Big Dummy at the time, but it was my bike that caught his eye.  I have no doubt that the owner had him converted to a Big Dummy shortly after I left the shop, but my bike and I had our moment.

I plan to return to the same shop after another 7 months and 500 miles.  The owner did a good job and seemed to know what he was doing.

How to Make the Bike Wagon Canopy for Xtracycles

Bike Wagon canopy

In a previous post I described a canopy that Thea and I made for our Xtracycle to protect her from wind and rain. It looks sort of like a covered wagon on the back of our bike. It was easy to build without special tools or parts, did not require modifying our bike and cost us less than $150 for parts. It weighs about 2 lbs. and we can set it up in less than five minutes. Here’s how to make it.

Materials You Will Need

Tools You Will Need

Ordering Suggestions

order from Quest Outfitters:

#1024 1.1 OZ SILNYLON 1STS , (Tan)…3 at $9.99 =  $29.97
#4060 TENT POLE W/ INS .625 18 inch Black…4 at $4.95 = $19.80
#4061 TENT POLE W/O INS .625 18 inch Black…1 at $3.95 = $3.95
#4018 TENT POLE W/INS. .340 18 inch Black…12 at $2.60 = $31.20
#4019 TENT POLE W/O INS .340 18 inch Black…2 at $2.20 = $4.40
#4055 TENT POLE ARCH-145 DEGREE .340 BLACK…4 at $2.95 = $11.80
#2000 WEBBING- NYLON MED WT 1/2 inch Black..25 at $0.49 = $12.25
#3026 SIDE RELEASE BUCKLES – 1/2 inch…4 at $0.39 = $1.56
#4200 tubing cutter…$7.95
#3235 grommet tool (5/16″)…$10.99
#3231 (10) 5/16 grommets…10 at $0.18 = $1.80

purchase at a hardware store:

(1) 7/8″ x 48″ dowel…$3
(4) 3/4″ long wood screws…$1
(4) #6 x 3/4″ machine screws and nuts…$1
25 feet of light tie-down cord such as cotton clothes line…$5

TOTAL: $145.67

How to Make the Canopy Cover

The rectangular canopy cover fits over the canopy frame and is secured at the bottom with tie-down straps. The front and back of the cover can be cinched up with a drawstring like a covered wagon. If you like, the cover’s size can be adjusted, along with the frame’s pole lengths, for different sizes of passenger. The size I give here is appropriate for a large child or small adult.

How to Make the Canopy Frame

How to Assemble the Canopy

CAUTION: do not leave your canopy frame uncovered. Without the cover it is only held together by friction. If jostled it could come loose and snap back with surprising force (and for example break a garage window as I learned from experience). DO NOT ride your bike with an uncovered frame (again as I learned from experience you don’t want to be picking up all 20 tent poles in traffic). If you want to use the frame for some purpose other than the Bike Wagon canopy, consider putting a shock cord within it or using external guy wires as I do for using it to support my solar panels.

Final step: do me the courtesy of sending me a photo of your finished canopy!

How to Cut an Aluminum Tent Pole with a Pipe Cutter

How to Add a Grommet to the Canopy Cover

How to Make a Canopy Sack

If you have enough cloth left over you can use it to make a canopy sack.

Cargo bike economics, part 2

In my last post, I wrote about a few of the implications of riding my electric cargo bike from a financial and social point of view.  Today I’ll tackle another topic that I’ve been pondering: how much extra time do my cargo bike errands cost?

My first errand under the stopwatch was picking my kids up after school.  As sometimes happens, I was late leaving our house, so I had to literally sprint the half mile up the hill to the school.  When I pulled into the parking lot, I was surprised to see that I had done it in 2 minutes!  Sure, I had cranked those pedals pretty hard, but you can keep up a pretty good effort for an interval that short.  While it’s true that I could get there a little faster in a car (possibly even a minute faster), I would spend much longer waiting to get through the traffic jam in the parking lot, so the bike wins this contest easily.

For my next errand, I needed to pick up a few items for dinner from the closest grocery store.  The route winds through neighborhood streets for 1.7 miles, descending about 500 feet.  The bicycle route tool in Google Maps says it should take about 8 minutes; it actually took me 9 (I got stuck at a red light for a long time).  I spent 11 minutes finding my groceries in the store, and then I pedaled back up the hill in 9 minutes (no significant traffic light delays in this direction).  So, my total errand time was 29 minutes.

To compare, I jumped in our mini-van as soon as I got home so I could measure the same errand in the car with the same traffic conditions.  I got to the store in 6.5 minutes, and the return trip took 7.5 minutes.  The total errand time would have been 25 minutes.

Although the car would have saved me 4 minutes, this was really a best-case scenario for the car.  There was very little traffic at this time of day, and there were plenty of parking spots.  Many times I spend several minutes looking for a place to park.

To be fair, there are many errands in the 5 or 10 mile range where the car is much more efficient time-wise, especially if the route uses a freeway outside of rush hour.  If you’re thinking about buying a cargo bike, you will have to determine whether the kinds of errands you do make this feasible for you.

The terrain is also a factor.  Google estimates that my return trip from the grocery store should have taken more than twice the time it did.  Without the electric motor, the time and effort would force me back into the mini-van on many days.  I really can’t imagine using this bike without some kind of assistance on these hills.

Sloshed!

Today along with my normal grocery haul, I added two propane tanks to the load on my cargo bike.  I was happy that they fit nicely in my saddle bags along with several bags of groceries.  The Hammer Truck continues to impress me with its versatility in this respect.

My wife was a little concerned when she saw what I was planning to do.  “Please be extra careful,” she said.  “Those tanks will be like bombs if you get hit.”

Since I haven’t had any close calls on this bike, I wasn’t worried.  The propane tanks weigh 17 pounds each, but I regularly ride with both my son and daughter on the back of the bike (downhill only… going uphill with that much weight is beyond my ability, even with the motor).  And with my kids on it, even though the center of gravity is higher, the bike still feels stable.

But today when I reached a steep downhill and was coasting at about 30 miles per hour, the bike began to oscillate side to side.  Each oscillation got stronger and stronger, and I had to slam on the brakes to avoid losing control.  I wasn’t sure what was causing the oscillation, but I figured it had something to do with the tanks.

Sure enough, when I got home and shook the tanks, I discovered that they are not full.  There is plenty of room for the liquid inside to slosh around.  The sloshing must have synchronized between both tanks.  Having 30 pounds of liquid moving back and forth at that speed is hair-raising, to say the least!  Afterwards, I kept my speed under 20 miles per hour, and I had no further problems.

In the future, propane tank transport will likely be one of the errands I save for the car.

The Most Heroic Hero of the Decade, Maybe the Century

If you are Quaker (as I am) the biggest thing to shake up Meetinghouses and make young friends’ hearts throb all over the country is Jon Watts. I first heard about him when his video “Friend Speaks My Mind” made the rounds around Ithaca Monthly Meeting. Besides being very funny, with lots of Quaker in-jokes, this video had a further resonance for me. It single-handedly brought into the open an issue that has been festering unspoken: are all Quakers Christian? I’ve longed to affirm in some way that I am a Quaker but not a Christian for a long time. But I was always afraid that others in the Meeting might be offended. Jon finally puts into words what so many of us have been feeling:

I’m not a Christian but I’m a Quaker
I’ve got Christ’s inner light but he’s not my savior

So that’s number one why Jon’s my hero. Number two I discovered reading the Xtracycle forum Roots Radicals. Someone mentioned a young man riding an Xtracyle Radish from Richmond to Boston on a music tour. Sure enough: Jon Watts! Furthermore, he’ll be going through this area. You can read about his tour on his blog. I am looking forward to seeing him at the Farmington-Scipio Spring Gathering. Why is he biking? He writes:

Why not just drive a car like any other rational American would?

It would be easy for me to spout off a guilt-based justification about how quickly our society is killing the Earth, and how each of us is individually contributing a great deal to that destruction by owning and over-using personal vehicles. And it would be true. I do feel guilty and hypocritical about simultaneously mourning the destruction of the natural world and contributing to it.

But the deeper reason why I am riding my bike the 600 miles to Boston: I find driving, for all of it’s convenience, to be spiritually deadening. So let’s turn the question on it’s head… why, when I could be actively using my body, engaging with the land and the environment around me, viscerally feeling the miles go by underneath me, and genuinely living would I isolate myself in a sound-proof, wind-proof, experience-proof chamber?

Why in the world would anyone do that?

Don’s New Year status report (2010)

It has been a couple of months and a couple hundred miles since my last post.  I really intended to update my blog more often than this, but it’s more fun to ride my bike (even when the errands are rather mundane) than to sit in front of my computer.  However, there have been many ups and a few downs since November, so I will try to catch my blog up.

The Hammer Truck continues to be a great bike for us, and I owe you another post or two to describe some of its features.  But it’s really the electric motor that makes the whole thing practical and fun in our abundantly hilly neighborhood.  On the flip side, the electric motor has also been the source of a few challenges.

Specs

Our motor is the BionX PL-350, with a retail price close to $2000.  I haven’t done a thorough comparison of different motors, but this one seems like it’s optimized for biking enthusiasts.  It’s relatively lightweight, very quiet, and supposedly maintenance-free.  But the features that really set it apart are torque sensor activation and regenerative braking.

Torque activation feels really cool when it is working the way you want.  The system senses the amount of torque you are applying to your pedals, and it kicks in additional power from 35% to 300% of your torque.  You determine how much assistance you want by selecting one of four assistance modes on the handlebar controller.

Regenerative braking allows you to reduce your speed and put some charge back in your battery while extending the life of your brake pads.  There are 4 generation modes that increase the drag on your back wheel and put increasing amounts of electricity back in your battery.  There’s also an option to activate the highest generation mode when you start to apply your rear brake.  I really like that feature.

Pros and cons of electric assistance

During the first week or two, I rarely used anything but the maximum assistance mode (level 4, 300%).  It’s frankly thrilling to blast up pretty steep hills at 10 m.p.h., to sprint away from stoplights as fast as most cars (at least until they shift!), and to haul kids around with less effort than going solo on my traditional bike.

With more experience, however, my strategy has become a bit more nuanced.  Assistance level 1 (35% additional torque) makes the unloaded Hammer Truck feel like an average weight bike.  It’s great for level ground or a light head wind.  Levels 2 and 3 are good for moderate hills when I don’t feel the need for speed.

For a while, I was fiddling with the regenerative levels a lot.  I would sometimes put it in a high regenerative mode and pedal downhill, reversing the direction of my battery meter by a click or two.  However, one day when I was doing that, the rear wheel suddenly locked up.  After some investigation, we found that I had shorn off the axle nut of the rear wheel.  After that, I’ve been quite cautious about pushing the limits of this bike/motor combination.  Since the motor wasn’t especially designed with a loaded cargo bike in mind, and since the bike wasn’t really designed to be motorized, and since our hill probably puts us in the 90th percentile of steep neighborhoods, I’m feeling that extra caution is probably the best course for now.

Bionic legs

When you match the power mode to your legs and an appropriate gear on your chain-ring, the reward is great.  With each stroke, you feel a surge of power, as if Lance Armstrong’s legs have been grafted onto your body.  In power mode 4, you might be even better than Lance!  It’s a beautiful marriage of man and machine – the kind of thrill you had the first time you rode your bike faster than you could run.

However, this is a great solution only for someone who likes to bike already.  It’s not a moped!  It works best when you’re putting in some effort yourself, not just coasting along and letting the motor do the work for you.  As a matter of fact, if you’re not pedalling, the motor isn’t working either.

I spend a lot of time in my higher gears, even going uphill.  Since the torque I’m exerting is pretty high, the motor is putting in a high level of effort as well.  If I get tired and shift to a lower gear, the motor seems to scale back as well, so I end up going slower with only slightly reduced effort.

Once mastered, the combination of Hammer Truck and BionX motor enables many kinds of errands by bike.  It extends your speed, your practical distance, and the amount you can comfortably haul.  And of course, it’s fun – I look for any excuse to get on my bike now.

But is this the bike that will get millions of people out of their cars?  I don’t think so.  It’s a little quirky and the learning curve is a bit steep.  Although it’s a good first step, the ultimate bike will be designed with an integrated motor from the outset.  There are already a number of electric bikes in a traditional form factor.  I haven’t seen a cargo bike with an integrated motor, and we may have to wait awhile for that.  For now, this is a pretty good alternative to a second car for many of our errands.