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