Battery pack.

Minimalist Cargo Biking

Every week during the summer I have to bike about 12 miles round-trip to pick up my farmshare vegetables. My route consists of three miles on a beautiful rails-to-trails path through the woods, three miles straight uphill to the farm, and then six miles home straight down Troy Road at speeds that can reach 30mph. Needless to say, I usually take my cargo bike for this task. Last week, however, I decided to try a new bike, the one-speed Dahon Boardwalk folding bike. This is Dahon’s bottom-of-the-line model, available at Walmart’s for $320, that I have been calling the Featherweight Folder on the Boxy Bikes website. What possessed me to take this toy-like bike on such a treacherous journey? I wanted to find out the minimal possible equipment necessary for the job. And, it turns out, less can be more.

There are many minimalist trends these days: minimalist hiking, minimalist running, and fixie bikes come to mind. The idea is that as you remove complexity from a product or an activity you find new freedoms. You can carry a fixie up a flight of stairs. You become more connected with the road. You are freed from servicing derailleurs and brakes. Several years ago I bought an electric cargo bike because I wanted to unencumber myself from all the complexity of the predominant method of carrying cargo, the automobile. I felt I did a pretty good job of downsizing my ride, from 3,000 pounds to 80 pounds. But last week I did a bit more downsizing. By carrying my veggies in a backpack while riding my Featherweight Folder, I reduced my cargo vehicle’s weight from 80 pounds to 36 pounds.

Of course all of this would not be possible without an electric hub motor. It would be quite an ordeal to ride three miles uphill on a one-speed bike. The hub motor eliminates the need to have more than one gear. That is not to say that I only use the motor and don’t pedal. I soon found with all my ebikes that no matter how many gears they have, I usually put the bike in the highest gear and never change to a lower gear. I ride by getting the bike up to speed with the motor, and then pedal to maintain my speed.

I have outfitted the Featherweight Folder with a tiny 4-pound geared hub motor. In general I prefer hub motors on the back wheel, but I put the Featherweight Folder’s motor on the front wheel since the back wheel’s hub is already in use as a coaster brake. The motor’s controller and a tiny 36v 5ah model airplane battery fits into a small pouch attached to the handlebars, and adds an additional four pounds to the bike. The bike itself weighs 28 pounds, so the total weight is about 36 pounds.

The Featherweight Folder handled the task of picking up my farmshare admirably. Even though the motor is only rated at 250w, I ran 600w through it for extended periods and it did not get hot. For comparison, humans output about 100w of power, so this bike has six times the power of a human cyclist. The trip used about 150wh of energy. Think of this as the amount of power needed to light a 150w light bulb for one hour. The rate of energy use worked out to about 13wh/mile. Compare this to 20wh/mile for a typical ebike and 35wh/mile for my Xtracycle cargo bike. However, the trade-off was speed: the trip worked out to about 12mph compared to 20mph for a typical ebike or 25mph for my cargo bike. This bike reminds me to slow down and enjoy the scenery.

The main drawback to the Boardwalk is that its coaster brakes can get very hot on long descents, especially if a nervous rider rides the brakes all the way down a hill. So I’m very cautious and I  use them sparingly. Replacing the coaster brake with a second V-brake would be better (though the cable might interfere with the folding and it wouldn’t work as well in the rain as a coaster brake), but a disc brake would be best.

What freedoms does the Featherweight Folder create? You don’t need a garage to hold it, for starters. Students can fold it up and charge it under their desks in their dorm rooms. You don’t need to bike both ways: you can fold it up and carry it on the bus or train. And one possibility I like is that in addition to the Featherweight Folder carrying me and my backpack, I can fold it up and carry it for awhile on a trip in which I alternately hike and bike. The Brompton website describes several such trips, including one in which two adventurers carried their rafts on their bikes and then carried their bikes in their rafts.

Where are things headed? What could be more minimalist than this? The next step I think would be a cargo skateboard. It sounds futuristic, but the folks at Grin Technologies have already come up with one that looks pretty practical. I think we’re just beginning to discover how electric motors can redefine what a bicycle is, from the largest of cargo bikes to the smallest of folding bikes and beyond.