Climbing Hills with a BBS01

19max10

Just Joined
May 4, 2020
3
0
Hi

Just completing my Bafang conversion. I already have a 2020 Cube touring hybrid pro 500 which goes like a train but is also about as heavy as one. I would like my new lighter bike to match the Cube's performance on hills. I've already discovered the standard 46T chain ring is too big; the bike goes up hills but struggles (even on the largest cog in my 11-40T cassette).

Will switching to a 44T chain ring solve my problems or should I be thinking of a bling ring (chainline issues?) or looking to alter the motor configuration.

Any advice much appreciated.
 

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,543
1,365
Tyne and Wear
I run a 42T Bling Ring and it gives me better chain alignment from the stock ring, and also increases the torque for stronger hill climbing. You may not have alignment issues, so theoretically you could use an even smaller chaining.

I'm a bit concerned that your bike is struggling up hills with your current set-up.
The Bafang BBSxx series don't like getting bogged down, and the motor needs to be kept running fairly fast, to prevent the controller from overheating. Also, keeping the motor spinning fast helps protect the internal nylon cog.

I would consider getting the chainring sorted sooner than later.

Once that is done, then you could consider a programming cable, which may give you some extra power depending on how your controller is currently configured.

Here's a useful thread, which includes the programming cable and Bling Ring links:

https://www.pedelecs.co.uk/forum/threads/after-market-bbsxx-crank-drive-gear.32691/
 
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19max10

Just Joined
May 4, 2020
3
0
I run a 42T Bling Ring and it gives me better chain alignment from the stock ring, and also increases the torque for stronger hill climbing. You may not have alignment issues, so theoretically you could use an even smaller chaining.

I'm a bit concerned that your bike is struggling up hills with your current set-up.
The Bafang BBSxx series don't like getting bogged down, and the motor needs to be kept running fairly fast, to prevent the controller from overheating. Also, keeping the motor spinning fast helps protect the internal nylon cog.

I would consider getting the chainring sorted sooner than later.

Once that is done, then you could consider a programming cable, which may give you some extra power depending on how your controller is currently configured.

Here's a useful thread, which includes the programming cable and Bling Ring links:

https://www.pedelecs.co.uk/forum/threads/after-market-bbsxx-crank-drive-gear.32691/
Thanks for your rapid response - much appreciated. I have fitted a Lekkie 42T Bling Ring and the gearing is much better now, and the chain line is improved as bonus.

I've ordered a programing cable, though it hasn't arrived yet. There's a lot of different advice around about what to tweak, but upping the Keep Current seems to be one thing which everyone agrees on so that's where I'll start. Beyond that I'm not sure.

On my Cube when I change down on a hill I get an immediate kick up the backside from the motor. On my Bafang it's almost the opposite - I seem to get less assist. No doubt I'll have to adjust my technique, but at the moment I'm very frustrated.
 

701

Finding my (electric) wheels
Jul 19, 2020
7
0
I too was very disappointed on first ride, but the throttle gives full power.

The Keep Current was set to 20%, upping that to 60% made it run more how you would expect.

The other thing is the motor's natural rpm is way lower than my usual cadence and changing to a lower gear and spinning up the pedals coming up to a hill drops the assist considerably which is a bit annoying. So back on the throttle again....
 

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,543
1,365
Tyne and Wear
If I've read int
I too was very disappointed on first ride, but the throttle gives full power.

The Keep Current was set to 20%, upping that to 60% made it run more how you would expect.

The other thing is the motor's natural rpm is way lower than my usual cadence and changing to a lower gear and spinning up the pedals coming up to a hill drops the assist considerably which is a bit annoying. So back on the throttle again....
You'll probably find that the issue is still the 'Keep Current' set too low. The way I think it works, is that the controller drops the current available, once the pedals are spinning fast, down to the percentage set in the 'Keep Current' tab.

I have mine set at 100%, but I've tested with lower percentages and it just doesn't work on hills.
Put it this way, why drop available current on hills, when you need max torque, to a level that bogs the motor down. This is not only crap for actually climbing the hill, but can potentially damage the controller.

Nope, 100% 'Keep Current' is the way to go, for me anyway!
 

701

Finding my (electric) wheels
Jul 19, 2020
7
0
Yes you are likely right as it still feels less than an old Bosch motor on another bike.

The problem with upping the Keep Current is when you are around max speed i.e. 15 (17) mph the cutout is very abrupt and it surges continually as the power comes in and drops again. Any tips for this?

I tried upping the max speed to 20 but with added muscle power it just moves the problem up the speed range to typical flat road speed...
 

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,543
1,365
Tyne and Wear
It's difficult to know what to suggest, without actually riding your bike and playing with the programming settings personally. Unleashed, the BBS01 is probably capable of 20mph+ on the flat consistently. The only thing stopping it doing that, is the speed limit on the 'Pedal Assist' tab. I guess it only does this surging thing, when it reaches the cut-off speed on your highest PAS level? I shouldn't imagine any lower settings can reach the cut-off speed, but I may be wrong and it depends how yours is programmed.

Now you mention that it does this abruptly, so if it were me, I would lower the 'Speed Limit [%]' on the 'Basic' tab, so it softens the abruptness as it approaches cut-off speed. You would probably only need to adjust the levels where you can actually reach cut-off speed under motor power. Lower 10% each time to find a nice balance.

I might be talking a load of twaddle though, so be sure to pop back on and see if this theory makes any difference. It's all a learning game, after all :D
 

19max10

Just Joined
May 4, 2020
3
0
Update....my programming cable arrived at last. I t took me an hour to find and install the Windows 10 driver but after that it's surprisingly simple to configure things. As a first step I've upped the Keep Current to 100% and the bike is transformed with no reluctance to climb! I still need to tweak the settings further e.g. PAS levels 1 - 3 are too high, but with the bike now working more as I had hoped, I can take my time and enjoy riding it and setting the motor up exactly as I want it.

Thanks Fordulike for your help - much appreciated.