New Bafang Crank-Drives

[DaveTheWave]

Kepler - thanks for the confirmation. So much to learn about this stuff...

 

[t3sla]

I believe they are using the same model naming style as hub motors.
So a BPM 350W and a BPM 500W is still a BPM

BBS01 is still the same for model name for 250W to 750W

I think this was all conceived before 750W entered a production, because it mechanically different form a 250/350 and warrants a variationin naming (unlike that of it's BPM counterpart)

 

[Goodies]

A couple of questions about the bbs-01.

Does it work without the display/throttle. If so what PAS level does it default to?

Does it work without the speed sensor, and just a throttle?

Where can one order the larger 52t chain wheel?

 

[Kepler]

I believe they are using the same model naming style as hub motors.
So a BPM 350W and a BPM 500W is still a BPM

BBS01 is still the same for model name for 250W to 750W

I think this was all conceived before 750W entered a production, because it mechanically different form a 250/350 and warrants a variationin naming (unlike that of it's BPM counterpart)

Thanks for that t3sla. So I have ordered the 750W BBS02. I wonder if it turns up with a coaster brake, what ever that is.

 

[t3sla]

It won't be a coaster brake (pedaling backwards lock the rear).

Supply chain seems to just be labeling the 750W as the BBS02

I'd like to get official clarification from BF if the literature has changed, the problem is online stores have such a hive mind mentality due to search algorithm indexing.

From my point-of view BBSXX was just a way of keeping track of what revision it was, not an indication of it's power rating.

 

[jerrypa]

On a side note, looks like bafang uses three different types of LCDs. I wonder what's the difference with the third one. The second one seems the nicest of all but I'm super concerned of theft. It's very fancy. The C950 which is what I have would appeal to less people as it shows vel, odo, dst. To someone in the US, that probably just means it is some kind of speedemeter and distance measurement screen. Probably wouldn't steal it as much as the chrome-bezel looking C961.

The C963 also seems a bit fancy with the piano black finish.

The downside to my C950 is the fixed KM/H display.

The C963 has real time power info (in watts) but also only displays in km/h and has a small but high quality screen. The C961 has the 6 hex bolts securing it and the controls onto the handlebar. Unless someone wants to remove all 6 bolts and steal a display with a proprietary plug that will work with nothing else, I think it's a non-issue. That is of course, unless someone with the same drive system but an inferior display, a bike multitool and a lack of morality happens to encounter an unattended bike with the BBS system :lol:

Have anyone found good video where these C950 and C961 are together? I understand that the and biggest difference is the separate button panel for C961?

 

[Melbourne]

A couple of questions about the bbs-01.

Does it work without the display/throttle. If so what PAS level does it default to?

Does it work without the speed sensor, and just a throttle?

Where can one order the larger 52t chain wheel?

Display-No Throttle-Yes most likely not work without the display ..but why won't you use the display? you can't turn on the motor/change settings!

Yes work without speed sensor but will get error code on display

i tried looking for 52T but found nothing.... so i bolted on my old 50T on the 46T chainring, not ideal as the chains is not align perfectly, I think 52T is too big for the 350w motor to turn...i am runnning 50t with 11cogs... torque/acceleration drop quite alot.

 

[crossbreak]

Where can one order the larger 52t chain wheel?

if someone finally tells me the BCD i can make an adapter for 130mm BCD race bike chainwheels... not a problem. If I produce some more of these I can sell them for less than 10 bucks.

 

[speedmd]

Hi Crossbreak

There is a ( Cup ) jog in the ring out near a 42 tooth diameter to help clear the motor/gearbox. A 130mm spider diameter ring will not work with this kit unless you mount it further out from center line. May be best to use the stock ring as a hub for a large (center cut out) ring if your looking for more top end.

 

[crossbreak]

hm... this guy did it... 130mm is a lot smaller than 42t dia.

http://cyclurba.fr/forum/231178/mot...651&messageID=263186&rubriqueID=102&pageprec=

 

[speedmd]

Is that a 750 watt unit. The smaller ones are not as wide going by the posts.

 

[crossbreak]

ok i get it, it's visible well on this pic
http://cyclurba.fr/forum/231178/mot...651&messageID=231178&rubriqueID=102&pageprec=

would indeed be possible to mount it using spacers to gain the same clearance for the gearbox.

 

[speedmd]

Hi Crossbreak

It is only to preserve a narrower chain line. Good move as it is a bit wide compared to road setups. It is a 6 mm jog and starts at around 150mm diameter. The 48Tooth sprocket has plenty of meat below the teeth to add mounting holes for adding a larger sprocket (with center cut out) on the inboard side. Could also do A cart multi pc sprocket for 219 chain as this is known to be a chain breaker. 3 or 4 speeds with 219 chain rear cogs would be something if you could get them to shift like a narrow chain setup or just go to a internal geared hub.

 

[--freeride--]

I got the 750W version since yesterday. And will supply all the data to crossbreak. The trany cover of the secondary reduction is of plastik. So it might be possible to grind it down for more clearense. An adapter only makes sence with additional shims to adjust the distance between the trany cover and the sprocket perfektly.

 

[Warren]

I don't understand the desire/need to change the chainring on the 750. It puts out too much power for a derailleur system to hold up for long. Just run a BMX chain to a IGH or NuVinci, and get on with riding.

 

[speedmd]

Some just prefer a "fas hoss".

"A reg'lar long pedigroo iz not important for a fast- trotting hoss" Josh Billing

 

[Warren]

"Some just prefer a "fas hoss"."

A typical 9 speed IGH with a 16 tooth cog, and the stock 48 tooth chainring on the 750 watt, will get you a higher gear than a 60-11 setup with a derailleur!

 

[Samd]

SRAM dual drive? IGH plus derailleur?
http://www.sram.com/sram/urban/products/sram-dd3-24

I think IGH only runs about 92% efficiency, versus about 98% for a derailleur. Some folks may care?

 

[Kepler]

I am not ready to dump the derailleur just yet. Those IGH units weigh close to a small geared hub and don't shift under load. For me the whole point of going crank drive is reduce unsprung weight and to retain a quality wheel set.

Will be interesting to see if my opinion changes after a few months of running 750W through a derailleur

 

[Geebee]

SRAM dual drive? IGH plus derailleur?
http://www.sram.com/sram/urban/products/sram-dd3-24

I think IGH only runs about 92% efficiency, versus about 98% for a derailleur. Some folks may care?

The Dual Drive is direct drive in middle gear, so as long as you use middle gear for the majority of riding the extra loss would be negligible

 

[Samd]

Those IGH units weigh close to a small geared hub and don't shift under load.

Shifting under load is something I'm very mindful of when I get back on one of my Aprilias. Good call Kepler.

 

[speedmd]

"A typical 9 speed IGH with a 16 tooth cog, and the stock 48 tooth chainring on the 750 watt, will get you a higher gear than a 60-11"

Hi Warren
No doubt, but it does not look anywhere near as cool. 8)

 

[Goodies]

I'm not looking to add a derailleur, I just want as big a chain ring as possible to go as fast as possible. I have a nexus 7 rear hub, and all my cycling is flat so I don't need heaps of torque, just fast RPM at the rear wheel.

Display-No Throttle-Yes most likely not work without the display ..but why won't you use the display? you can't turn on the motor/change settings!

Stealth, and because I'll have to change the wheel diameter to get past the speed limit so a lot of the info it shows will be useless to me.

 

[Warren]

A Nexus 7 speed, in high gear, with a 16 tooth cog run off a 48 tooth chainring, turning at 90 rpm, will go about 32 mph. This is as fast as the 750 Bafang at its 25 amp controller limit, about 1200 battery watts, will push a bike on level road. Running a bigger chainring will just overheat the motor.

This is equivalent to a 52-11 derailleur setup, which would eat chain like mad. I suppose you could justify going to a 60 tooth chainring to run a 13 tooth high gear in back, and improve chain life. But a derailleur chain still won't last as long as a BMX chain through a 16 tooth IGH cog.

 

[Geebee]

How is a Nexus going to last on 750w ? My Tonaro with a Nexus 8 feels like it is near the limit on the 250w rated drive (36v at 17a peak), adjustment has to be exact, on really steep hills I have had to add a secondary stop to prevent the arm twisting, it sometimes feels like it is vibrating? and shifts have to be precise. I am just ok with it at this power level but any higher would be worrying.
None of these occur when running human power only