I am part way through a scratch build and wanted to make sure I had my head screwed on right before I spent a lot of money on a crank drive. The bike (see picture) is loosely inspired by c. 1920 motorcycles. I'll explain why I want a crank drive, and which one, after a short preamble so that it becomes clear why the bike is the way that it is.
Firstly, I wanted it to be a capable pushbike. It is huge and it isn't light but it all works just fine. The huge painted rims rule out rim brakes, so I have a disk on the rear, and as the springer forks don't have a mount point, I have a Sturmey Archer drum brake on the front. Gears are essential where I live, so there is a Shimano Alfine 8 speed hub on the rear. So no spare hub ...
The bottom bracket is a sodding awful old-school BMX size. I've used an adaptor and it has a standard UK threaded bearing with a tapered spindle and taper cranks.
My first choice for a crank drive would have been the Bafang, but visual inspection of photos suggests there isn't space between the motor and the integral spindle for my old-school BMX oversize bottom bracket (58mm?).
My next choice would be the GNG 48/60V brushless chain drive. Or possibly the older model with the belt primary. I'm even wondering if I can tilt it over inside the frame. The GNG looks a bit micky-mouse, but might fit with the overall look of the bike.
My last choice would be the Cyclone. It just looks naff. That tensioner looks like something I would do when I can't be arsed to do it properly. Perhaps I am misjudging it.
Is there anything I've missed? Any better ideas or suggestions?
Lastly, I'd like to run 48V LiPoFe4. I've never ordered batteries, and the whole battery thing is doing my head in. I'm fine with electrical stuff and had planned to build a custom removable battery frame to sit inside a varnished wooden cabinet inside the bike frame. I like the ease with which Headway batteries go together. Is there a similar but better choice? Who would be the supplier of choice?
Sorry to trouble you with the usual questions, but as you can see, nothing is entirely normal in this build, and I can't afford to make a mistake