Having bought a cargo bike for moving my kids around – well knowing that the factory installed hub motor was underpowered, it also turned out that my recent purchase had a broken battery. Diving into stuff like this is always quite rewarding when it comes to obtaining new knowledge – this being no exception…
Being able to carry six tiny kids or four decent sized ones, swapping the whole drivetrain seemed like the right thing to do in this case.
To get started I picked up the following items:
- Bafang MM G340.500,
- Bafang Display DP C18.UART
- Greenway LG2600 16Ah battery
The first bump in the road was that the rear wheel had to go in order to get rid of the old motor.
Fair enough, but the choices available when shopping for a 24″ wheel with disc break mounting weren’t overwhelming.
I think the one I ended up buying was from thansen.
Although the ground idea was to re-use as much of the original parts as possible, I constantly got tangled up in catch 22’s. Not being a bike mechanic by profession, I was unaware of the existence of screw-threaded cassettes. Regardless of that – I was forced to go for the freehub approach when buying the new rear wheel, as other (sensibly priced) options was quite hard to come by.
Bye, bye screw-threaded cassette….
The factory mounted six-speed grip shift system was fairly intact, but getting a hub to hold a six speed cassette was also hard to find – at least since there apparently are different standards to deal with in this area as well.
Turning sour on the whole thing, I decided to scrap the six-speed system and go for a completely new seven-speed system.
Along the way i picked up a nice set of new tools to deal with hubs, though…
….as getting all the way in there outreached what my selection of Allen wrenches would do in terms of caliber and length. Of course – this was completely unnecessary because I ended up putting the hub that came with the wheel back on when moving to the seven-speed system.
Once that was out of the way, putting it back together was a walk in the park – and whatever extra width the new seven-speed cassette added was neglectable.
Mounting the new motor was not difficult at all – except for one thing – a special key was ‘needed’ in order to tighten the lock nut completely.
I managed to find a ‘Bafang Wrench BBS02/BBSHD Mid-Drive Installation Tool’ on eBay or AliExpress for next-to-nothing, and it did it’s job flawlessly.
The new drivetrain now has a milage of approximately 1500km, and is about to complete it’s second winter of daily use. Everything is holding up quite well, but a new chain might be nice to get once the spring hits.
