New Bafang Crank-Drives
- Thread starter d8veh
- Start date
spinningmagnets
100 TW
Thats a good experiment, if someone could hold up a 110-BCD chainring to the BBS02 drive sprocket, that would tell everyone if the mount bolts would rub against the housing. If 110-BCD will work, I agree the wider range of tooth-counts would make it a better choice...
edit: Google shows
104-BCD = 32T-48T
110-BCD = 34T-60T
130-BCD = 38T-60T
http://www.vueltausa.com/se-chain-ring-110mm-34-60t-1.html
edit: Google shows
104-BCD = 32T-48T
110-BCD = 34T-60T
130-BCD = 38T-60T
http://www.vueltausa.com/se-chain-ring-110mm-34-60t-1.html
Geebee
1 kW
Could you reverse the original ring and drill and fit a standard road ring thus keeping alignment?
Alternately on a recumbent trike (ultra long chain so no alignment issues) could you just drill the original ring and fit a standard road ring, leave off the gaurd is necessary. Maybe even allowing the front derailleur to work?
Alternately on a recumbent trike (ultra long chain so no alignment issues) could you just drill the original ring and fit a standard road ring, leave off the gaurd is necessary. Maybe even allowing the front derailleur to work?
--freeride--
100 W
- Joined
- Jul 5, 2011
- Messages
- 237
Crossbreak and I start to produce lasercut stainless steel 104mm 4 arm Adapters with shims to adjust the chainline.
48T up front is more than enough.
At 110 crank rpm what should be possible on the 48V system and 48T up front 13T in the rear:
26 wheel = 53km/h or 33mph
29 wheel = 57km/h or 35mph
110 crank rpm is pretty fast but you will only use that on short strokes using the thumbstrottle, so that should be ok.
At 90 crank rpm on the 48V system and 48T up front 13T in the rear:
26 wheel = 43km/h or 26,7mph
29 wheel = 46km/h or 28,5mph
Thats a good speed for traveling with the 750W system, there is not enough power to go a lot faster.
The diameter where the 5 mounting holes are on is 60mm, the inner flansch is 50mm.
48T up front is more than enough.
At 110 crank rpm what should be possible on the 48V system and 48T up front 13T in the rear:
26 wheel = 53km/h or 33mph
29 wheel = 57km/h or 35mph
110 crank rpm is pretty fast but you will only use that on short strokes using the thumbstrottle, so that should be ok.
At 90 crank rpm on the 48V system and 48T up front 13T in the rear:
26 wheel = 43km/h or 26,7mph
29 wheel = 46km/h or 28,5mph
Thats a good speed for traveling with the 750W system, there is not enough power to go a lot faster.
The diameter where the 5 mounting holes are on is 60mm, the inner flansch is 50mm.
amigafan2003
1 kW
Greenbike kit now have the 48v750w system.
http://www.greenbikekit.com/index.php/bafang-8fun-mid-crank-driving-bbs-02-kit-48v-750w-central-driven-motor-kit.html
How easy is it to overide the 25km/h speed limit?
http://www.greenbikekit.com/index.php/bafang-8fun-mid-crank-driving-bbs-02-kit-48v-750w-central-driven-motor-kit.html
How easy is it to overide the 25km/h speed limit?
mwkeefer
1 MW
amigafan2003 said:
It's simple, get the kit and by the time you have it... Ill have posted a FULL technical breakdown with mods and all
I'm even working at reverse engineering the CPU and EEPROM to decode the communications protocol and offer a open source software package for changing the settings...
Be patient
Mike
amigafan2003
1 kW
mwkeefer said:amigafan2003 said:
It's simple, get the kit and by the time you have it... Ill have posted a FULL technical breakdown with mods and all
I'm even working at reverse engineering the CPU and EEPROM to decode the communications protocol and offer a open source software package for changing the settings...
Be patient
Mike
Wahey!
Kepler
10 MW
It's simple, get the kit and by the time you have it... Ill have posted a FULL technical breakdown with mods and all
I'm even working at reverse engineering the CPU and EEPROM to decode the communications protocol and offer a open source software package for changing the settings...
Be patient
Mike
Great stuff Mike. This will make a lot of people very happy who currently watch this thread.
So how far have you got with the reverse engineering so far? Can you see yourself having a solution before the end of the year?
eride
10 mW
spinningmagnets said:The French pedelec forum http://www.cyclurba.fr has a member selling a 4-arm 104-BCD spider, CNC aluminum, with chainrings available from 32T-48T. This is probably appropriate for France since they have significant mountains (Tour de France, etc), but for US customers, perhaps a 5-arm 130-BCD spider might be more appropriate. A quick Google shows chainrings are readily available from 38T-60T.
I don't know if the bikemotive spiders will fit, could someone post the interface of the BBS01-2? :
I want to try the BBS02 on my soon to be delivered Alligt Sunrider II (A9-kit) with chainring 75T. They deliver chainrings 39T-80T that fits a 130-BCD spider. http://www.alligt.nl/
Attachments
footloose
10 kW
Mike, Warren --
Thank you both for insights!
On previous foot-propelled setup, I had 52-tooth chainwheel driving 16-tooth sprocket with Shimano 8-speed IGH.
Was pretty much ideal.
On current setup, I swapped in some massively strong BMX chain after popping 'normal' chain, and had to move to
18-tooth sprocket to make it work (previous chain had a 'half-link' to make it fit... but that wasn't where it busted).
Have ordered some BMX chain composed entirely of half-links. If it works as expected, will be both strong and
enable me to go back to 16-tooth sprocket.
After riding few more miles... convinced that on any but steepest hills, the gears below 5 aren't going to get much use.
And if they do, I'm going to be hunched way over the front wheel to keep it near the ground
Mike -- sign me up for one of your chainwheels when available. Not the gigantic recumbent one, but larger than 52 teeth.
Toughest thing to get used to may be the effect of relatively slow ramp. I'm used to Mac setup, where throttle is
'twitch and go'. 1-2 seconds ramp in this setup doesn't sound like much, but it really does
mean some planning ahead, and careful takeoff from stop. Hit the pedals too hard in first second of pedaling,
and the bike kind of slingshots out of the hole.
Thank you both for insights!
On previous foot-propelled setup, I had 52-tooth chainwheel driving 16-tooth sprocket with Shimano 8-speed IGH.
Was pretty much ideal.
On current setup, I swapped in some massively strong BMX chain after popping 'normal' chain, and had to move to
18-tooth sprocket to make it work (previous chain had a 'half-link' to make it fit... but that wasn't where it busted).
Have ordered some BMX chain composed entirely of half-links. If it works as expected, will be both strong and
enable me to go back to 16-tooth sprocket.
After riding few more miles... convinced that on any but steepest hills, the gears below 5 aren't going to get much use.
And if they do, I'm going to be hunched way over the front wheel to keep it near the ground
Mike -- sign me up for one of your chainwheels when available. Not the gigantic recumbent one, but larger than 52 teeth.
Toughest thing to get used to may be the effect of relatively slow ramp. I'm used to Mac setup, where throttle is
'twitch and go'. 1-2 seconds ramp in this setup doesn't sound like much, but it really does
mean some planning ahead, and careful takeoff from stop. Hit the pedals too hard in first second of pedaling,
and the bike kind of slingshots out of the hole.
--freeride--
100 W
- Joined
- Jul 5, 2011
- Messages
- 237
mwkeefer said:It's simple, get the kit and by the time you have it... Ill have posted a FULL technical breakdown with mods and all
I'm even working at reverse engineering the CPU and EEPROM to decode the communications protocol and offer a open source software package for changing the settings...
Be patient
Mike
Perfekt!!! I tried to find someone that could change settings over here in germany, but even King-Meter where the display is comming from doesn't do that...
Will it be possible do change parameter that have effect on the cut off time when you stop pedaling? I want that as short as Possible.
I allready got the motor so let me know when you are ready. I would be very happy to test allound.
@ Warren: I ride 26X2.4 tires on my freeride bike. In the french forum someone postet that the 48V Motor is doing 140rpm on the crank with no load. Lcrewse told me 110rpm when you use throttle and the cadence is not limited, so the 110rpm on the crank with full load should be realistic.
@ eride: the sunrider is nice, let us now how fast you are going when you installed the kit. If nobody is doing an 130mm adapter, what I don't think, you could drill the holes for the 130mm Chainring into the original Chainring and cut off the outer ring to make it a spider. That should be doable with a standard drill. I think you should get a 90T Chainring or even bigger, 90T-13T 110 crank rpm on 20inch wheel would be 72km/h that should be easily doable on a sunrider. The power of the 750W unit should be enough to get it over 80km/h when you pedal hard.
Kai
10 W
- Joined
- Aug 4, 2008
- Messages
- 86
greenspark said:
My bottom bracket is too narrow inside and doesn't accept the bafang drive. Could you show me what kind of reamer tool you used to ream the bottom bracket to 33,5 mm?
Did you just re-thread the existing threads longer all the way through? If you used a reamer, I hope your process didn't destroy original bottom bracket threads.
Kai said:
I used a Dremel with a stone then switched to abrasive roll on my cannondale. It did not harm the BB threads as long as you don't grind on them. Took about 30 minutes of grinding then checking then grinding some more. Total material removed was probably .010".
speedmd
10 MW
Warren said:
Looks like the stock 48 ring with a second 56 tooth front ring attached is top of the list to try out for a commuter setup. Should be a easy mod.
spinningmagnets
100 TW
The French have the Alps, and also severe speed limits, thats why their first upgrade was the smallish 104-BCD 4-arm spider (32T-48T). They couldn't imagine anyone needing more than 48T.
I think a 5-arm spider is much more stable than a 4-arm. 130-BCD chainrings are very common and cheap, but they only seem to go down to 38T, where the 110-BCD go down to 34T.
I would recommend a 130-BCD for two reasons. For hill-climbing, its better to raise the tooth-count at the rear wheel sprocket, so more teeth are engaged. Spreading the load for less tooth-skipping on a power-spike, also wearing-out slower.
If you raise the tooth-counts at the rear wheel, I don't think the low 34T chainring of a 104-BCD would be needed by anyone (since 130-BCD goes down to a fairly low 38T), especially with a cassette at the rear instead of a 7-speed freewheel.
The second reason is that the stock drive sprocket has a top-hat shape to clear the secondary reduction housing even with this factory off-set, mwKeefer has had difficulty with the chainline after trying the drive on several bike frames. a 130-BCD spider would provide the most options for experimenting with off-set and double chainrings.
I personally don't think double chainrings are necessary, but I enjoy experimenting as much as the next garage enthusiast, and there's no reason to purposefully exclude them as an option. 20mm of extra diameter doesn't sound like much, but every mm helps.
If two separate guys want to make different spiders (110 & 130), it's best to let the market decide, but...if the collective desire of the group will only support one spider to stay in production, I highly recommend a 130-BCD (38T-60T available off-the-shelf).
I think a 5-arm spider is much more stable than a 4-arm. 130-BCD chainrings are very common and cheap, but they only seem to go down to 38T, where the 110-BCD go down to 34T.
I would recommend a 130-BCD for two reasons. For hill-climbing, its better to raise the tooth-count at the rear wheel sprocket, so more teeth are engaged. Spreading the load for less tooth-skipping on a power-spike, also wearing-out slower.
If you raise the tooth-counts at the rear wheel, I don't think the low 34T chainring of a 104-BCD would be needed by anyone (since 130-BCD goes down to a fairly low 38T), especially with a cassette at the rear instead of a 7-speed freewheel.
The second reason is that the stock drive sprocket has a top-hat shape to clear the secondary reduction housing even with this factory off-set, mwKeefer has had difficulty with the chainline after trying the drive on several bike frames. a 130-BCD spider would provide the most options for experimenting with off-set and double chainrings.
I personally don't think double chainrings are necessary, but I enjoy experimenting as much as the next garage enthusiast, and there's no reason to purposefully exclude them as an option. 20mm of extra diameter doesn't sound like much, but every mm helps.
If two separate guys want to make different spiders (110 & 130), it's best to let the market decide, but...if the collective desire of the group will only support one spider to stay in production, I highly recommend a 130-BCD (38T-60T available off-the-shelf).
"In the french forum someone postet that the 48V Motor is doing 140rpm on the crank with no load. Lcrewse told me 110rpm when you use throttle and the cadence is not limited, so the 110rpm on the crank with full load should be realistic.
I wouldn't be doing any useful pedaling for more than 30 seconds at 110 rpm, but I know pro racers can. And if you use any chemistry other than LiFePO4, the voltage will drop off pretty quickly, so you will soon be down closer to 90 rpm.
I wouldn't be doing any useful pedaling for more than 30 seconds at 110 rpm, but I know pro racers can. And if you use any chemistry other than LiFePO4, the voltage will drop off pretty quickly, so you will soon be down closer to 90 rpm.
speedmd
10 MW
130 mm bcd is not a good choice for this kit IMO. It will force you to go to a wider chain line. Looking like something in a 155 -160 bcd minimum to go inboard the stock ring. 144 bcd / 42 tooth rings look like they will rub the case without some serious mod and leaves not much meat to mount it, just going by a quick looksee. I have to find/ make a thin spacer for mine and will see what will fit and clear the chain stay a bit closer over the weekend. If mounting a second or larger ring outs side of stock ring, its mount will need to go outside the inward jog the stock ring makes and most stock chain wheels will need to be opened up to clear the stock rings jog/ center. Something like a 44 -54 would work well on this and give a much broader speed range and allow more use of larger rear cogs.
spinningmagnets
100 TW
Thanks for posting that speedmd, I don't have one of these drives in my hands, so I was just daydreaming about options.
Installed a cheap mod Watt meter on my BBS01/bottlebattery 9Ah/BH neo battery 9Ah.
Just warning for you guys... my 350W36v BBS01 blow up my BMS on a BH Neo Emotion Battery (~2 weeks back)... i think its because when i use the Throttle it draws 28Amp (1000w)... not like printed on the motor of 18Amp...lol. I could easier do 50 kph (~31mph) with throttle/hardpedalling.
My morning commute ~18kms – started with 39V
36.77Vm
27.85Ap
140.6Wh
4.106Ah
1022.9Wp
Ah displays the total charge in Amp hours delivered to the load since power was applied to the Watt's Up. It is measured on the load side.
Wh displays the total energy delivered to the load in Watt hours since power was applied to the Watt's Up meter. This is measured on the load side.
Ap displays peak Amps as the maximum current drawn on the load side.
Vm displays the minimum voltage or “droop” measured on the source side.
Wp displays Peak Watts as the maximum power drawn on the load side.
Just warning for you guys... my 350W36v BBS01 blow up my BMS on a BH Neo Emotion Battery (~2 weeks back)... i think its because when i use the Throttle it draws 28Amp (1000w)... not like printed on the motor of 18Amp...lol. I could easier do 50 kph (~31mph) with throttle/hardpedalling.
My morning commute ~18kms – started with 39V
36.77Vm
27.85Ap
140.6Wh
4.106Ah
1022.9Wp
Ah displays the total charge in Amp hours delivered to the load since power was applied to the Watt's Up. It is measured on the load side.
Wh displays the total energy delivered to the load in Watt hours since power was applied to the Watt's Up meter. This is measured on the load side.
Ap displays peak Amps as the maximum current drawn on the load side.
Vm displays the minimum voltage or “droop” measured on the source side.
Wp displays Peak Watts as the maximum power drawn on the load side.
footloose
10 kW
OK, first daylight stone cold sober review
I bought 750w setup from lcrewse. Arrived nicely packaged within a couple days. Fast response on questions. Paired it with '50v' battery from EM3ev.
Build? Piece of cake. Only issue was removing some slag from bottom bracket of vintage '80s Raleigh Twenty. Great bike, but construction was spotty at best. Wiring harness? Plug and play. Adaptation of battery to new kit? Minor.
First ride the night I got it hooked up? (You know the moment, realization of "hey this thing could run now..."). Fun but scary. Found myself riding up hill with front wheel in air.
So went out for "rational" test ride today. 10 miles, on the flatlands. Started with battery about 3/4 discharged, cause I wanted to know what happens when LVC cuts in.
Impression? On 8 speed IGH hub, not much need for anything below 5 on flats.
With 5 power settings x 8 gears... Too many choices, put it in 5 / 5 and ride.
And if that isn't perfect, the n use the throttle!
Pedelec basically bogus concept. I wasn't really adding power... Was just rotating the pedals to get power input.
Not scientific, but first impression: Fun.
I bought 750w setup from lcrewse. Arrived nicely packaged within a couple days. Fast response on questions. Paired it with '50v' battery from EM3ev.
Build? Piece of cake. Only issue was removing some slag from bottom bracket of vintage '80s Raleigh Twenty. Great bike, but construction was spotty at best. Wiring harness? Plug and play. Adaptation of battery to new kit? Minor.
First ride the night I got it hooked up? (You know the moment, realization of "hey this thing could run now..."). Fun but scary. Found myself riding up hill with front wheel in air.
So went out for "rational" test ride today. 10 miles, on the flatlands. Started with battery about 3/4 discharged, cause I wanted to know what happens when LVC cuts in.
Impression? On 8 speed IGH hub, not much need for anything below 5 on flats.
With 5 power settings x 8 gears... Too many choices, put it in 5 / 5 and ride.
And if that isn't perfect, the n use the throttle!
Pedelec basically bogus concept. I wasn't really adding power... Was just rotating the pedals to get power input.
Not scientific, but first impression: Fun.
spinningmagnets
100 TW
Footloose, Other posters have indicated that when you give a motor some gears to work with, it can broaden its performance envelope, at the expense of having to shift once in a while (normally using only 2 or 3 gears).
Have to ever ridden a 48V X 25A = 1,200W direct drive hub? If yes, how does this drive at 48V stack up as far as performance "feel"?
Have to ever ridden a 48V X 25A = 1,200W direct drive hub? If yes, how does this drive at 48V stack up as far as performance "feel"?
Geebee
1 kW
Re the pedelec lower the assist level until you are adding some human power to maximize range, on a lower powered system you just pick a higher gear until you are adding some power yourself, with 750w I suspect you won't have a gear that high
footloose
10 kW
spinningmagnets said:
My other main ride is 48v X 25A Mac setup. I'll test more this weekend, but initial feel is that this setup gives a much broader range of "feel" , but overall very equivalent performance. They both have more power than a normal
person really needs, and they can each kick a--s. On this setup.... You you just have so dang many "virtual" gears.
8 gears x 5 power ranges.... Cool, but many of the combos duplicate each other, like a classic 3 x 7 derailleur setup.
Some folks have talked about need to slack off power when shifting.. To me, not an issue. Just feels natural, like motorcycle gear change... You back off power, shift, pour it back on.
The way I'd ideally ride this setup... Put it in one gear, then vary the power assist from 1-5. I'm not saying it is efficient or logical.... Just that it might feel very natural to "shift" power assist rather than gear ratio with this kit.
