I love my Workcycles KR8, but unfortunately after 2 years pedaling up hills, my toddler and I are getting too heavy. The electric version of the KR8 isn’t available in Australia, but after a lot of googling I felt like a bafang BBS01 might fit….
And it does, very nicely!
There’s actually room in the frame to mount it on the chainstay behind the seat tube, which is very unusual, but allows normal ground clearance. Plus gravity and the torque of the motor are working in the same direction so hopefully it will stay nice and snug.
I bought the kit from Dillenger Australia, not much more expensive than direct Chinese import, plus I get parts I know will work together, a bag of tools and good customer support.
I used the same gearing my bike came with, 38T chainring and 20T rear cog. This is at the lower limit of what the Shimano 8 speed nexus is spec-ed for apparently. I bought the California EBike 104 adaptor and a 38T chainring from ebay to reuse my chain and keep the same low low gearing. Unfortunately it took some careful sanding of the inner portion of the chainring to make it fit – perfectly in the end.
I’ve mounted the battery (designed for bottle mounts on a downtube) by drilling a row of 6 carefully places holes in the back plywood paneling, and it now lives under the seat with the power wires coming out another hole I drilled in the back. (Shh: two plastic tabs protrude and get in the way of mounting it flat and had to be cut off) I also used two strips of balsa wood I had handy to act as bracing either side of the metal mounting rail since it’s hanging horizontally, rather than vertically, and this should help spread the load. Extra bolts also help spread the load. It’s a heavy battery.
This set up works very well too. On the flat to mild hills I’ve mostly used 2/9 to 6/9 power. On max assistance (9/9) it makes going up hill feel like I’m peddling down hill. On the very steepest hills (the ones under powered cars feel as well) I’ve noticed it’s still quite a bit of work, but the thumb throttle can actually give you a boost beyond what full 9 out of 9 power give you. All in all turns out 250W is plenty for getting about on a lumbering Cargo bike.
I’ll try and add more photos soon. Feel free to ask any questions or comment below.