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Terence R. McCain researched how to build a bike that could help him haul supplies from town to his home. He decided he wanted an electric cargo bike. An energetic retiree, McCain had to go out of state to find a bike shop with “experience selling several models of cargo bicycles, and retrofitting electrical systems on bicycles.” He shares with us his experience designing this custom electric cargo bike, which he is expecting to be delivered in January.

Like many Americans, I began riding a bicycle as a kid. I still like bikes. I’d love to use a bike for local shopping. The grocery store is less than 2 miles from my house. Wal-Mart is 5 miles. Downtown Warrenton, Virginia is less than 3 miles away. There’s really no reason to use my van for most of those trips, except for one little thing.

My bicycle – an 18-speed mountain bike – doesn’t have a trunk. I can’t put 80 lbs of groceries on the bike because there’s no place to put them. And if I could put them on the bike, the local hills would probably defeat me. I’m not as spry as I used to be.

Maybe an electric bike would do the trick?

Lots of electric bikes are coming onto the market now, and that’s a good thing. But they all seem to have one thing in common: still no trunk. Most have enough power for the rider, and no more. Their gearing lets them help the rider sustain maybe 18 mph or so, but they have virtually no torque at lower speeds, so they’re useless for any sort of hauling. I couldn’t just stick a bicycle trailer behind one and expect to get up the local hills, pedalling or no pedalling.

My project is to specify and acquire an electric bike that overcomes those limitations. A bike that is useful for hauling a considerable cargo and tackling the hills in my county with ease. A bike that I could reasonably use in lieu of my van for most local trips.

No such bike exists on the market in the US. But the components do exist. So last summer, I hooked up with a small, progressive bicycle shop in North Carolina (Cycle 9) and began figuring out how we might do it. Here’s what we eventually came up with.

Frame

Big Dummy 2.JPG

Surly Corporation’s Big Dummy ). This is an extended frame intended for hauling cargo, made in the US. Surly isn’t making a lot of these yet; most buyers have to wait a few months to get their hands on one. The frame is designed to carry a 200 lb rider and over 200 lbs of cargo.
(Photo from Surly’s web site)

Panniers

FreeLoader.JPG

Xtracycle‘s FreeLoaders. These are extra-large American-made panniers with an integrated rear deck which can swallow a whole lot of groceries. The Big Dummy frame was specifically designed to work with Xtracycle’s oversized accessories.(Photo from Xtracycle’s web site)

Battery

LifeBatt’s 20 amp-hour, 48-volt LiFePO4 battery. This very large battery from Taiwan (nearly 40 lbs) will be mounted on the Freeloader’s rear deck, leaving the panniers free for cargo.

Propulsion

Two hub-mounted 400-watt electric motors manufactured by BMC. These motors are internally geared to deliver better torque at low speed than most other motors on the market. The motors will both be controlled by a single grip throttle. They’re made in India.

Trailer

cycletote.jpg

A Cycletote lightweight aluminum cage trailer, with a custom hitch mount fabricated by Cycletote for the Freeloader’s rear stays. This American-made trailer can haul up to 150 lbs or so, with only a fraction of that weight landing on the bicycle frame. Unlike some bicycle trailers, this one attaches at the bike’s center, and so doesn’t pull the bike sideways as you ride. (Photo from Cycletote’s web site. The Rubbermaid box shown on the trailer is sold separately.)

Additional Notes

There are a lot of other details involved, of course. The Big Dummy is sold as a frame, not a complete bicycle, so we’ve had to build the bike up from scratch, using components from all over the world.

Note: The obscurity of some of the manufacturers involved is extreme. BMC has no web site. They employ a single individual to manage all of their North American operations. The battery vendor we chose (in Taiwan) takes orders in English and ships anywhere in the world, but has no American operations and an international web site that is confusing. You really have to know what you want before you talk to them.

Cycle 9, my builder in North Carolina, has sold electric bikes before, but nothing aimed quite so specifically at cargo-hauling and low-speed torque over hilly terrain. A lot of person-hours went into researching components and working around glitches that they could never recoup from the sale of a single bike. Hopefully, they’ll be able to produce more bikes like this one, now that they know where the sand traps lie.

I expect to take delivery of the finished bike in January. I have no idea what its range will be or how much cargo it will haul up hills of varying slopes. I’ll find out.

Electrifying a bike is easy compared to electrifying a car, and it just makes sense to me to want to set up an electric bike so it can do some hauling over short distances. We’re accustomed to using our cars for hauling, but a bike like this one should be an able substitute for local trips. Electric cargo bikes have the potential to become ubiquitous.

And that could make a very large difference in our lifestyles. Less pollution, more exercise, more fun. That would be a very good thing for America.

I’ll post more about Terence’s bike once he has put some miles on it.

remake-sm.jpg
If you have a project that makes a difference, let me know about it — dale at oreilly dot com, and I’ll share it on a future Remake.

Dale Dougherty

I’m founder of MAKE magazine and creator of Maker Faire. I am CEO of Maker Media, the company that produces MAKE, Maker Faire and Maker Shed. I am Chairman of the Maker Education Initiative (www.makered.org).


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Comments

  1. Nick says:

    I’ve built and used cycle trailers before, and I quickly discovered that mounting the hitch point high causes trouble.

    When you lean into the turn, if the hitch point is high, the trailer gets twisted away from its direction of travel, causing the tires to jump, and the whole trailer to jitter and wobble. Its managable if the trailer is lightly loaded, and you’re moving slowly. but at even at modest speeds, and with a load, the effect tends to be quite violent…

    I solved the problem by making the draw bar on my trailer longer (the draw bar on the pictured trailer is quite long, which will probably help) and by mounting the connection point lower – I made a hoop that went around the cycles back tire, and mounted the trailer-hitch under that.

  2. peter says:

    I’ve used high & low hitch trailers before & prefer high hitch. I built a trailer for my 11′ skiff with a hitch to the seat post & it works flawlessly from walking speed to 30 mph, no wobble, no jitter. The combined trailer & boat & gear is typically around 200 lb. You hardly notice it on the flats or turns, only on the uphills.

    The hitch I made was simple, I V-notched the end of the tongue (wood, 2×3), bolted a short (1′) crossbar a few inches back (doubles as a handle) and bungeed a foot of PVC with some innertube. To hitch up, I pop the seat post & put it through the PVC tube.

    If I were building a cargo trailer for an electric assisted bike I’d be inclined to put the hub motor and battery on the trailer itself, making it somewhat self-propelled, just to help it get started and/or climb hills.

  3. Terence says:

    I’ve got the Cycletote trailer on hand, but the bike I will use it with isn’t here yet. So the value of my opinion remains to be seen.

    At this point, though, my opinion is that the Cycletote ought to work pretty well with a high hitch.

    The hitch is fully articulated, so in ordinary use, it shouldn’t much affect the attitude of the bike, even going over fairly rough terrain.

    Because the hitch is in the centerline of the bike, it won’t be pulling the bike off-balance.

    The trailer has some virtues, too. The wheels are 26″ x 1.75″ bicycle wheels, and their height permits the bed to be situated well below the center of gravity for the trailer. The trailer won’t be top-heavy unless it’s piled pretty high. The wheels are also canted inward at the top, adding a bit of extra stability.

    I plan to use the trailer pretty much as shown in the photo. There will be a plastic tub in the cage to keep dirt and rain off the cargo.

    I like the idea of adding propulsion to the trailer itself, but I think with all the torque from the Big Dummy’s hub motors, I probably won’t need it. At full throttle there’ll be in excess of 90 ft-lbs of torque at low speed, plus whatever I can add by pedaling. That may not be much by automotive standards, but for a bicycle it’s monstrous.

    But I admit, there are a lot of different ways to do this. I hope we’ll hear from others with different solutions.

  4. alandove says:

    I applaud this guy’s enthusiasm, but he really should try simpler solutions first.

    I’ve said it before and I’ll probably have to say it again: if you want to learn how to use bicycles as practical transportation, begin by visiting China. All of this Western-style reinvention of the wheel would probably give the average Chinese citizen a good laugh (and maybe it does, if the Make blog is readable through the Great Firewall).

    The Chinese use bicycles the way Americans use pickup trucks: as general-purpose hauling platforms for any cargo under a half-ton. This is not done with custom-designed bikes, or overengineered electrical assist devices, and it only occasionally involves trailers. In most cases, the bike simply sports a super-heavy-duty luggage rack on the rear, plus a large basket on the handlebars. All loads pile onto one of those two points.

    I’m certainly not in the same league as the Guangzhou deliveryman, who thinks nothing of putting 300 pounds of office watercooler refills on his luggage rack, but I’ve piled some sizable loads onto bikes over the years. Keep the weight low and over the rear wheel, and don’t hesitate to use (or install) an ultra-low stump-pulling gear to grind up the hills. It isn’t fast, but it works.

  5. Terence says:

    Even in China, the convergence of two trends in bicycles, electrification and cargo utility designs, is in its infancy. The reason is simple. Most electrical bicycle components simply aren’t built for low-speed torque. They’re built to zip a single rider along at 18 or 20 mph. So while the Chinese may be masters of both cargo bicycles and electric propulsion separately, integrating them is fairly new territory even for them. And I assure you, they are not marketing anything remotely like an electrified cargo utility bicycle in the United States.

    You’re right, you *can* use an ordinary, unpowered bicycle to move heavy cargo. But it’s awkward, it takes a lot of setup and preparation, and you’re very glad when it’s over. In hilly terrain, it’s also the province of the young and vigorous rider. That’s fine for the young and vigorous, but there are a lot of potential riders out there who are left out if that’s our guiding design principle. Like me.

    By contrast, when you use the trunk in your car, you hardly even think about it, and there are no physical fitness prerequisites at all.

    That’s exactly what I want to achieve for hauling cargo on a bicycle. The capacity will be built-in, like a trunk, to be used or not used as needed. And I won’t have to worry if my spindly, aging legs can get me up the hill if I buy that extra 50 lbs of groceries. For the really big loads, I’ll have to hitch up the trailer, but the bike will have a good capacity for cargo even without the trailer, with absolutely no rigging or special preparation required.

    I looked at other bikes, including box-and-frame designs, before making my choice. I will not say the Big Dummy is better or worse than those designs, only that my personal preference is for a bicycle that rides like the recreational bikes I’ve ridden all my life, albeit with a power assist. And a trunk. With those guiding principles, the Big Dummy build is the result.

    There are countless alternative approaches to the problem, though. They’re all perfectly valid, so long as they meet someone’s need.

  6. alandove says:

    @Terence, I take your point. I think what I’m really arguing is that people should _try_ simpler solutions first, and only graduate to more complex/expensive options if that doesn’t work out. Personally, I’ve been amazed at what I can do with a modicum of determination, and while I’m not Medicare age yet, I’m no Spring chicken.

  7. Pekar says:

    a transmission seems necessary here. Personally I’d mate a single electric motor to a NuVinci hub with a dual drive setup like the staton-inc.com gas power assist bikes. I like the BMC hub motors, and would probably try to use one of those mounted centrally, like a stokemonkey driving the rear wheel.

    I’m sure you’re fairly committed at this point, so take this as food for thought, and kudos for your efforts!

  8. aktivator23 says:

    I have been researching electric bikes now for many hours per day for almost two months and I think i have been exposed to nearly every configuration out there. It occurs to me that this builder might be able to easily work with a very old line of bicycle called the “Worksman.” They have an entire line of very sturdy bicycles including tri-cycles designed for industrial uses. This link will take you to there site: http://worksmancycles.com/shopsite_sc/store/html/cruisers.html

    The first bike listed on the page is called the “Worksman Tough” which is a classic newspaper boy delivery bike. Very cool and not too expensive. You can even order a bare frame and build it up from that. The BMC hub motor is supposed to be able to provide low-end torque as it has internal gears. He might also consider the Phoenix Brute hub motor which is designed for torque as well.

    I live in the Bay Area of San Fransico and I recently spotted a cargo delivery bike with a torquey hub motor selling for $1900. Not too bad! Best of luck in your build.

  9. MyCargoBike says:

    I’ve been disappointed that there aren’t more developments in the electric cargo bike arena. Despite a flurry of interest a year or two ago, the only bikes of this kind on the road are still custom builds. But they can work really well! I haul kids and groceries up steep hills in Seattle on a daily basis — see my video at http://www.youtube.com/watch?v=VIea5W4U8Wc

    You can read more about my experiences with this bike (a Rans Hammer Truck with BionX motor) at http://www.MyCargoBike.net

    I hope your bike is working out well, Terence!

  10. zmalik says:

    amazing….. it think it will bring comfort to many people……
    car trailers for sale

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