Monthly Archives: June 2016

E-cargo Part 2

Cargo bikes are great for transporting much more than conventional bicycles and with that advantage, of course, there is a downside – they are bigger and therefore heavier to pedal. For several years, I have been happy to do the extra work required in exchange for that benefit and have done most of my short distance grocery and other shopping trips with my cargo bike, but have not used the bike as much as I would have liked for longer trips.

In December,  2014, a new bike, the Biktrix Juggernaut, was introduced to Saskatoon, featuring an electric mid-drive. It was the mid-drive system used on that bicycle that caught my interest and the following summer, I contacted Biktrix owner, Roshan Thomas, and arranged to go for a test spin on a bike equipped with the Bafang system.

Wow – what a hoot that was, and it got me thinking about its application on a cargo bike. While short distance shopping trips are not difficult on a cargo bike, longer distances can be quite daunting due to the extra weight of a heavier bike plus its cargo. As one of my friends commented, electric assist changes a cargo bike into a regular bike when considering the effort involved. I decided to give the idea a try on the new bike that I was building.

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The Bafang mid-drive system has been on the market a relatively short period of time but has already received a lot of consumer attention and mainly good reviews. It is available in several models – after discussions with Roshan, I chose the mid range BBS02 36 volt 500 watt unit, and coupled it with a Panasonic 36 volt 14.5Ah lithium battery pack for my new cargo bike.

Installing the conversion is not difficult. Bearings, bearing shells and crank are all removed from the bottom bracket and the drive unit slides in. Controls include throttle, on/off/power level selector and brake levers that cut power when  brakes are applied. A large readout panel displays speed, distance travelled, power level selected and battery level. The unit is programmed to engage when the crank is pedalled forward or when the throttle is used. Other programming options are available.

Unlike rear hub electric motors, mid-drive systems retain the advantage of whatever range of gearing that  a bike may have. They can be coupled with rear derailleur systems or with internal geared hubs. Derailleur systems are inexpensive but require more attention in shifting when using electric assist, and can result in jerky and stressed gear changes. Internal hubs eliminate that concern and I chose another newcomer on the market, the Nuvinci N360 continually variable hub – it represents the latest in technology.

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This is what the new drive system and rear hub looked like on the new bike.

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The battery is mounted on a rear carrier, over top of the drive wheel. The Bafang unit is not obtrusive – rather it looks like it belongs where it is.

This is the view from the cockpit. The Bafang read-out is large and easy to read. The NuVinci twist-grip shifter displays speed settings as a gradient.

So, how does it work? It is a bit early for a full assessment but so far, I am very pleased with the results. The Bafang powers the bike very well and the NuVinci hub makes changing speeds a breeze. After  more than 30 kilometres, the battery is still at 80% charge. I have been out for several short distance shopping trips and have travelled in record time. The bike moves along easily at 25 km/hr, even with a load of groceries on board. I have not tried for a top speed but have been over 30 km/hr, which for a cargo bike. is moving right along!

More photos to follow in the next post, and a follow-up after the bike has logged a few miles and done some work to earn its keep. Cheers.

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E-Cargo – Part 1

Good ideas are meant to be improved upon, right? And so my first long john cargo bike led to the second “improved” version. And from there it followed, there had to be yet another “improved” one.

As it turned out, the donor bike for  the next long john cargo bike to come out of Village Cycleworks was the Nishiki bike pictured in the last photo from a previous post – a bike that had been abandoned in a nearby back alley long enough that grass had grown up among its severely bent front forks. I brought it home on long john cargo bike #2 in 2014.

Next donor?

Work began in April, 2016 to transform the Nishiki mountain bicycle into a working cargo bike. Design and size followed much of what was done to build Bike #2, with a few changes. For one, instead of using the forks from a bicycle to brace the steering tube.EMT conduit was used. With the use of a borrowed pipe bender, 3/4 inch conduit was bent into gentle curves and then  3/4 inch flat bars were welded into place to provide a location to attach bottle cages later.

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I have always appreciated the X style step through bars that John Lucas of Cycletrucks uses on his bad-ass cargo bikes and so once again I shamelessly copied him and kept that feature.

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Components for my projects are a combination of new and salvaged items. The 1 1/2 inch square 16 gauge tubing used as cross pieces for the cargo deck were once the frame of a discarded piece of exercise equipment. The 1 1/2 inch round tubing with the nice bends were once roof members of a temporary tarpaulin shelter, also discarded.

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The most important change to the structure of this bike is the use of a heavy duty BMX threadless fork with incorporated V-brake mounts, sized to accommodate a 48 spoke, double wall, 20 inch front wheel and its heavy 14 mm axle. BMX bikes do not conventionally feature fenders and since I wanted fenders on this bike, I had to weld on provisions for that.

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Steering stops have been a challenge, and after messing around with an attempt at adjustable ones that did not work, I reverted to the KISS (keep it simple, stupid) approach, with pieces of flat stock formed and welded to the frame and the fork. Size and location was determined by trial and error, enabling a tighter turning circle than on the previous model.

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The double kickstand went together with relative ease, copying the one done on the previous bike.

Long bikes present unexpected challenges, such as  very long brake cables. With a wheel span of eight feet, the long john requires an unusually long cable to reach the front brake. Tandem bike cables are not long enough, and the cost of a custom made brake cable is prohibitive. On Bike #2 I came up with my own solution, which I used again in Bike #3. From a growing pile on my shop floor of cheap calliper brakes taken from salvaged bikes, I cut off threaded ends along with the barrel adjusters and then welded them in place on the underside of the cargo crossbeams.  Cable clamps, available at any hardware store, are used to extend the length of a regular brake cable. They may not look pretty but they do the job and they are out  of sight under the cargo box.

With the frame completed, it was time to put some temporary wheels on the beast and see how it was emerging.

After a quick spin around the block, it appeared that the new bike was going to work. Back into the workshop for some final touches. On previous bikes brake and derailleur cables were kept in place with zip ties. The zip ties are an easy solution to the issue of keeping cables in an orderly way but they are not particularly aesthetic. Using 3/8 inch round pipe, I fashioned cable leads, some single and where required, some double, and welded them in place.  I also installed some rivet-nuts in several locations to attach home made cable clamps for the electrical cables associated with the electric mid-drive.

 

Stay tuned for the big innovations to follow.

 

 

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