New Bafang Crank-Drives

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
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mwkeefer   10 MW

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Re: New Bafang Crank-drives

Post by mwkeefer » Jun 06 2013 8:23am

d8veh wrote:
t3sla wrote: For contrast the Ananda mid drive systems does 100N.m, with only 5A......dat gearing!
I'm not too sure where that figure comes from, but when I rode a bike with the Ananda crank-drive, it wasn't more powerful than the 250w Bafang CD., which means gutless!
mwkeefer wrote:jk1,

If I can increase current by 1/3 maximum and nominal it would produce 638w at 16.88 A and 48.13v by adding a shunt and increase the maximum to perhaps 22.45A as main battery maximum current for a total at 48v of 1082.925 watts and 68.15 ft lbs of torque.
The TMC unit is similar to the Bafang one. It has about the same power(riding experience). I increased the current from rhe standard 15 amps to 24 amps, but it didn't make much difference to performance. It just made the motor get hotter.
d8veh,

Based on your description / experience it sounds like somewhere between the two values there simply isn't enough mass or copper and the eddy currents begin to flow making a wonderful heater? I think my default on this is 16.8A with maximum of 17.08A. Using a piece of excercise equipment late at night and dialing up the resistance will alllow me to test with 1A increment at a time to find the absolute sweet spot between performance, economy and top speed.

I must ask how did you increase your current, if they are similar (or copies) then the controller is inside the drive? Just curious :)
I was thinking about this - it seems current wise this motor is just below saturation at 17.08 A Stock and want's 13S Lipo or 48v nominal to attain 88 RPM at the crank.

Unloaded @ .83A and 112.2 RPM

Max efficiency should be 82.6 @ 10.37A @ 413 watts and 37.1 NM Torque or 327.48 in lbs or 27.29 ft lbs
(*** This is equal or exceedings the torque provided by a stock 9C front hub with 36v and 22A Infineon Controller)

Max power should be at 638w or 16.88 A and produce 68.7 N.m. or 50.670519655329905 ft lbs.

Max torque will be at 554.19w or 17.08A and would be equal to 90 N.m. or 66.38059343493 ft lbs
(*** This maximum torque is 10 Nm higher than even the bosch drive system and with I believe a retail between 600 and 800.00 depending on parts included and longevity of the product - well that is seriously on par with hub motors but I've got a few hills most people walk up with their bikes...

Please feel free to examine my numbers, without replacing the stock controller or beefing it up I wouldn't exceed 15S or 55.5v nominal or 61.875 hot off the charger, it works with most stock controllers and should work with this one too... wish I could adjust the voltage divider but.. I can try it at 15S and pray the caps are 63v.

If anyone has gotten this model apart yet, please let me know the process please :)

BTW: Once I'm done testing this unlimited (no speed limit, throttle not linked directly to pedalec, works independent) on a bike or two I will be receiving my own sample units, 2 of each including the tool and programming adapter and software so I can configure these with physical speed limits, etc - They will be available for 36v and 48v but I will only stock a few until the 750w unit comes out and is made available through import channels.

This sample unit will be available within about a week (mostly bench testing, probably put about 10 miles on road tests) and I won't be testing at 18S due to the likely 63v caps... I will be offering it along for my cost (it wasn't cheap) + postage (Likely around $13-$18.00 priority mail. PM me if your interested the price I paid was $650.00 USD, first come first serve order :)

To be perfectly honest:
I just couldn't wait to test the units Ive already ordered for samples, they take weeks - this was available in the USA and with EMS shipping from china it's exactly what sample units would cost in single units, so for anyone else wishing to evaluate the Bafang Bottom Bracket 350w drive with LCD Control Dash, Internal Controller, 48.1v nominal pack - which provides 88 RPM loaded at the torque specified above or elsewhere but peaking at 90 N.m. on the stock controller with 48v at 17.08A and outputting 504 watts in stock format with the internal controller... that's pretty strong (stronger than the bosch and many other mid drive kits) and with the rear derailleur setup for 7 speeds (stronger chain) and tuned index shifters - this thing should be able to climb just about any mountain in the proper gear.

I can wait to punish a setup on the road when I get my own samples and can program the on board controller - (I do want to test any temp difference between having the controller onboard vs external lyen or methods or ecrazyman or sensorless RC controller like ICE HV40 - it may be a way to squeeze a few more amps in without generating as much heat.within the motor casing.

-Mike
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w

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Re: New Bafang Crank-drives

Post by d8veh » Jun 06 2013 2:02pm

I look forward to seeing your results.
The TMC motor uses a separate normal controller. I soldered the shunt in stages. The first few amps made a slight difference, but it still couldn't get up our test hill without pedalling, which a 250w Bafang hub-motor as a crank drive managed.

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Re: New Bafang Crank-drives

Post by jpo » Jun 06 2013 6:48pm

Question for anyone using and or testing one of these units.
It appears that there is only one free wheel in this drive unit. It is on the chainring/bb allowing rider to throttle without pedaling. As far as I can tell there is not a freewheel (or one way bearing) on the motor shaft, so if you pedal with motor/assist off you actually turn the motor. I have never seen a mid drive motor without a freewheel on the motor.
I'm looking for some real world experience. Who has tested this unit with power turned off?
How much drag is there? If I run out of juice on the way home am I going to wish I was on my regular bike.
All mid drives I've ridden pedal like regular bikes when the motor is off. There is no drag from the motor just the added weight.
thanks

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t3sla   10 kW

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Re: New Bafang Crank-drives

Post by t3sla » Jun 06 2013 9:05pm

t3sla wrote:
d8veh wrote:
t3sla wrote: For contrast the Ananda mid drive systems does 100N.m, with only 5A......dat gearing!
I'm not too sure where that figure comes from, but when I rode a bike with the Ananda crank-drive, it wasn't more powerful than the 250w Bafang CD., which means gutless!
Ananda yesterday, rep I was with said it can do 100N.m and has much more grunt than the BF.
TBH I recall more grunt from the Ananda (but not a large amount), that was on flat ground.
Ananda does use a torque sensor unlike BF which only has speed, so it would have been spurting a proportional amount unlike BF (hence the larger feel of power)

The 5A figure is from the brochure and I suspect that means it's for the pedelec market, not what the unit is capable of handling.
I'd bet money it can outdo a bosch :wink: but the BF still wins due to 68mm BB mounting :x
Just took a look at the website
http://www.ananda.com.cn/news_detail/ne ... d0f6d.html

M125-BBTR
-Rated power is 250 watt
-Maximum output power can be 400 watt.
-Highest efficiency can reach 80%
-Peak torque of 100N·m
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mwkeefer   10 MW

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Re: New Bafang Crank-drives

Post by mwkeefer » Jun 06 2013 9:08pm

jpo wrote:Question for anyone using and or testing one of these units.
It appears that there is only one free wheel in this drive unit. It is on the chainring/bb allowing rider to throttle without pedaling. As far as I can tell there is not a freewheel (or one way bearing) on the motor shaft, so if you pedal with motor/assist off you actually turn the motor. I have never seen a mid drive motor without a freewheel on the motor.
I'm looking for some real world experience. Who has tested this unit with power turned off?
How much drag is there? If I run out of juice on the way home am I going to wish I was on my regular bike.
All mid drives I've ridden pedal like regular bikes when the motor is off. There is no drag from the motor just the added weight.
thanks
The resistance is minimal, there is an internal one way bearing or freewheel with a tiny bit of resistance you pedal against... I presume with use it will loosen up a bit but I can spin the crank with 2 fingers and almost no effort in the pedal direction so you should be fine :)

-Mike
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w

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Re: New Bafang Crank-drives

Post by jpo » Jun 07 2013 12:34am

mwkeefer.
That is definitely not he case with the unit i have. When I turn the pedals it turn the motor. There is a fair amount of resistance and I can hear the wine of the motor turning. I've seen one way bearing get stuck on mac and bmc hub motors after lots uses. I have one that is starting to stick occasionally but it's been in service for at least 7000 miles.
I would be very happy if there was a one way bearing in there. Problem is if it is stuck where do i find a new one?

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Re: New Bafang Crank-drives

Post by d8veh » Jun 07 2013 3:39am

jpo wrote:mwkeefer.
That is definitely not he case with the unit i have. When I turn the pedals it turn the motor. There is a fair amount of resistance and I can hear the wine of the motor turning. I've seen one way bearing get stuck on mac and bmc hub motors after lots uses. I have one that is starting to stick occasionally but it's been in service for at least 7000 miles.
I would be very happy if there was a one way bearing in there. Problem is if it is stuck where do i find a new one?
The free-wheel must be jammed. I rode the Bafang, Bofeili, TMC and Ananda crank-drives, and they all worked like you'd expect. That is you can ride them like a normal bike without power.

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Re: New Bafang Crank-drives

Post by jpo » Jun 07 2013 8:57am

That is good news because I really like the design. If the one way bearing is stuck how reasonable would i be to replace it? Where would one find a replacement bearing? Or do you think it could be freed up with use? In other one ways I've had go south there was no recovery. Seems like maybe I would need to replace the entire gearbox. I have not taken anything apart. One way bearings often just slip on. No special tools puller etc to remove. The system is so new has anyone explored the inner workings yet?
Thoughts?
thanks

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Re: New Bafang Crank-drives

Post by t3sla » Jun 08 2013 5:26am

I tried riding with no power today, it sucked.
It's a test bike which is being whored out to different riders daily, so it's getting some good abuse on Chinese roads which should quickly weed out problems.

Initially I'd thought the bearing wasn't flush and causing some oscillating friction when pedaling.
But the factory technician informed me the crank isn't exactly free-wheeled exactly and uses a tooth spline like that of a a geared hub motor shell case.
Might just be hearsay lost in translation, I'd hate to be spreading misinformation so I'll ask another source.

I got the 'yeah it's not German' what cha expect look :o
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Re: New Bafang Crank-drives

Post by jpo » Jun 08 2013 11:11am

T3sla
I am not familiar or understanding what a tooth spline is. I thought most geared hub motors used one way bearings. Which while not exactly a freewheel they do spin with very little resistance. I would be perfectly satisfied with a one way bearing.

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Re: New Bafang Crank-drives

Post by o00scorpion00o » Jun 14 2013 1:48pm

Does anyone know where I can get the 350w version without speed limit ?

I presume the 750 watt isn't available yet ?

I would like to compare to the Bosch, the Bosch isn't a 250 watt system but more like 500 +

Did I read right that the Bosch has 70 nm torque ? The Bosch has 50 with 70nm rumoured for 2014 models.

I'd really love a Bosch bike but I would need to spend at least 3,000 Euros.

I can get the 350 watt in Dublin for 3200 Euros with gates carbon and Nuvinci hub.

Anyone know what this combination would be like to pedal ?

I could probably justify it if I could peddle it like a normal bike,and keep it for 6 or 7 years as I know the Bosch is plenty powerful for me.

It if the bafang could work at 400 euros - battery I'm all for it, having said that I would like a new bike as mine is getting a bit tired.
Haibike EQ Trekking, powered by Bosch.

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Re: New Bafang Crank-drives

Post by mwkeefer » Jul 04 2013 12:25am

Just a note for users of the 48v version - I've successfully run it on 15S on the bench and under light loads, in the process of installing and can't determine the differential of power or speed until I get it into the bike and on the road to gather data but 15S lipo seems to work okay so I would figure it's 63v caps minimum - I'll dissassemble a unit tonight to see the internal controller configuration and perhaps to plum an alternate controller (6 fET infineon) or maybe after an initial specs gathering run... Eagle Tree logger is configured for wheel speed, crank speed, GPS and a few temp sensors, I'm letting the CA manage the current and speed measurements based on wheel sensor... This should let me run and test at 12S, 13S (built a single cell 10AH chunk for testing), 14S and 15S for likely stock operation - I fear there may be some speed limiter as audibly (I know real scientific) 12S and 15S produced the same chain ring RPM (eagle tree wasn't hooked up).

This is going on a 26" dahon Jack until I can find or have made a suitable replacement chainring to run on a 20" folder, 48T just won't cut it, plus I needed to pull a GNGv2 to have it's plates replicated in harder steel and a few other niceties but since I'm moving and only have the RC Hard Rock (20 miles range if I'm lucky and real easy but it's like a sport bike so very difficult to keep the speeds down... or the front wheel) normal 16AH 12S pack 30C, and a Nova front wheel drive on 18S 20" folding bike.

Still need to pack, have about 1 full day left and only 1/2 way done but I also need to build a quick 15S charger for the 10AH pack I nailed together for the Bafang Crank Drive on the Dahon Jack.

If it proves to be insufficient for the Jack I will perhaps put it on an 8H or internal rear shifting 8 speed, gives a great advantage when used with a 48t primary sprocket.

-Mike
Regards,
Mike

{My Rides]
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w

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Re: New Bafang Crank-drives

Post by EVTodd » Jul 07 2013 10:31am

These new bottom bracket drives are actually making me want to try something other than friction drive :D .

Are there any dealers in the USA selling these yet?
New Tidalforce friction drive build: http://endless-sphere.com/forums/viewto ... 28&t=28029

My Friction Drive Outrunner Setup: http://endless-sphere.com/forums/viewto ... &start=330

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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 3:08am

jpo wrote:Question for anyone using and or testing one of these units.
It appears that there is only one free wheel in this drive unit. It is on the chainring/bb allowing rider to throttle without pedaling. As far as I can tell there is not a freewheel (or one way bearing) on the motor shaft, so if you pedal with motor/assist off you actually turn the motor. I have never seen a mid drive motor without a freewheel on the motor.
I'm looking for some real world experience. Who has tested this unit with power turned off?
How much drag is there? If I run out of juice on the way home am I going to wish I was on my regular bike.
All mid drives I've ridden pedal like regular bikes when the motor is off. There is no drag from the motor just the added weight.
thanks
I have a 300W (350W detuned to be legal in my country) BBS01 installed in a classic European 3-speed bicycle. When there is no power, the bike pedals like a normal bike. On the stand with the rear wheel in the air, turning by hand there is no resistance. No drag. Also, when one back-pedals, the chain does not operate the coaster brake. I am told that a future version will work with a coaster brake. My bike has both a coaster brake and a rear caliper brake, so no problems for me.

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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 3:09am

amigafan2003 wrote:Looking at that diagram - am I right that the crank doesn't have a freewheel? I.e. if the motor is powered the the pedals HAVE to turn as well?
No, that is not correct. I own one.

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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 3:56am

t3sla wrote:
jk1 wrote:The biggest problem with these kits seems to be the location the motor is mounted , you would have very low ground clearance ? it wouldn't be good for offroad use either
Yup, factory can't use them on step through frames which are big in Europe.
So what they have essentially done is wiped out a large proportion of their sales market (cheaper competition (against Bosch) for step through in Europe)
Mind bog-lining bad move.
...
So now it's essentially just for MTB frames, pinning it directly against the bosch system.
This assertion about blowing the European market is incorrect.

We have installed the BBS01 on a classic Italian "city bike" frame (see the photo). This one shows the BBS01 installed the men's frame, but the woman's step-through frame (with the Frascona curve) has the same mounting. In fact, the BBS01 seems to be directly targeted to the European market, where Bafang has a large presence and seems to invest a lot of effort to understand the European needs. Many European ebikes run Bafang motors under their own brand and specs.
BBS01.jpg
BBS01 Installed
BBS01.jpg (104.29 KiB) Viewed 4129 times
The biggest challenge in installation is the sloppy way some bike manufacturers finish the inside of their bottom brackets with tube protruding into the 33.5 mm shaft area. We've had to grind two bikes already to get the BB back to 33.5mm all the way through.

Another European-bike challenge was the chain guard. The bike above came with a fully encased guard made for a 42 tooth chain ring. The minimum chainring for the BBS01 is 46T. The BBS01 comes with a plastic chain ring cover, but for European riding (in street clothes) a chain guard is preferred. We used an after market guard (see http://www.rosebikes.com/product/detail/aid:161645) purchased mailorder from Rose Bikes in Germany and then used some empty threaded bolt holes on the motor to fabricate our own mounting to hold it in place. An aftermarket bike shop that installs these motors should advise the customer that fitting is at the hourly rate unless they get a large borer tool that will ream out the tube extensions rapidly. We are recommending to Bafang that they offer a special chain guard that will be made to fit the motor with universal clip for the top and rear.

Note how we addressed the battery issue. We use a 6.6aH A123 Battery from http://em3ev.com/ that fits perfectly in a Brooks Millbrook bag. This makes it a very subtle look, although some people think the ABUS Bordo folding lock is the battery or the controller. Having the controller in the motor is another nice feature... one less attachment on the bike, one less set of cables.

Note that pedalling up a few hills and then on somewhat level ground, the 6.6 Ah battery goes 25 km and still has juice it at the end of the journey. The secret is to pedal on the flat, and turn the motor off, only using it as an assist going up the hills (bicycling is supposed to be about exercise, right?). Our unit came with both pedalec and a thumb throttle, and we find the TT is especially helpful when joining traffic and needing instant power, not waiting for the motor to sense the pedals turning.
t3sla wrote: "...you would have very low ground clearance"
As the photo shows, the motor is almost in line with the crank shaft. The chain ring has lower ground clearance than the motor. Ground clearance has not been an issue, and we cannot see how it could be.

We are next going to install one on a classic Raleigh Dl-1 (that was in rough shape, not worth restoring as a historic). This will require reducing the width of the Raleigh BB to modern spec, but the measurements suggest this will not be a problem. That one is a 250W standard Euro spec motor. It will be interesting to see if it feels different than the 300W unit.

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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 4:06am

d8veh wrote:The worst characteristic is that the motor runs on a bit after you stop pedalling, which keeps tension on the chain. The tension makes gear--changing a bit traumatic, and probably impossible with Shimano hub-gears. I tried one with a Nuvinci hub, and it was a perfect match because you can change gear under load.
We have been using the 350W version (detuned to 300W to be street legal) on a classic European 3-speed bike and have spoke to Bafang about the shifting problem with a Shimano hub. The work-around is to disconnect the rear ebrake electrical shut-off cable and instead wire in an instant on-off switch in its place. Then when shifting while under power, press the button in the same way you would press a clutch on a manual transmission car. The brake cut-off is instant. Of course, if you set your rear brake a bit loose and keep the ebrake cable hooked up, you can goose the handle enough to cut power but not enough to cause the pads to hit the rim. A third way to deal with it is to stop pedalling for a few seconds before shifting... just like you let off the gas before pressing in the clutch on a car.

We found that after a few loud noises from the Shimano hub, the rider would break the old habit and learn a new one.

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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 4:20am

t3sla wrote:I tried riding with no power today, it sucked.
It's a test bike which is being whored out to different riders daily, so it's getting some good abuse on Chinese roads which should quickly weed out problems.

Initially I'd thought the bearing wasn't flush and causing some oscillating friction when pedaling.
But the factory technician informed me the crank isn't exactly free-wheeled exactly and uses a tooth spline like that of a a geared hub motor shell case.
Might just be hearsay lost in translation, I'd hate to be spreading misinformation so I'll ask another source.

I got the 'yeah it's not German' what cha expect look :o
We own one and find riding with no power (on the flat and down hills) is no different than before we added the motor. Took it out tonight to make sure and can assure you that in normal use on a normal bike, when the motor is not on, pedalling effort is no different than before the motor was installed.

As a test bike, it is possible that you were on a bike that had another problem, or that there was something defective with that particular bike or motor.

I have to say that when our team visited the factory and got a preview test of the BBS01 in January (seriously cold that day), it was not all that impressive. When we took delivery in March and began to use it as an everyday bike, it rapidly became the favorite bike in the stable. The most frequent description is that it is transparent - you forget it is there and only remember when the battery quits while going up a hill. It requires pedalling but provides a smooth and quiet assist; it just makes you feel stronger than you really are.

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Re: New Bafang Crank-drives

Post by DIY_turbo » Jul 08 2013 6:41am

When we took delivery in March and began to use it as an everyday bike, it rapidly became the favorite bike in the stable. The most frequent description is that it is transparent - you forget it is there and only remember when the battery quits while going up a hill.
Hi greenpark - nice assesment of the Bafang

Does the small heat up fast?

How does the controller react to the PAS ?

Thanks

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Re: New Bafang Crank-drives

Post by t3sla » Jul 08 2013 7:15am

Thanks for that awesome feedback! Especially about the BB.
The chain guard is a pretty big issue and is something highly valued by EU customers, they love their commutes

I would may have overstated blowing the EU market off with their low clearance move, I'm talking about low step through frames that have low ground clearence
My understanding i they're s 2:1 of step-through to MTB in the pedelec market (I can't find a figure to support this, but it's what I've seen from an export side)
North europe is a little different due to their increased height and 700C preference, but the rest mainly deal with a a medium size frame and 26" wheels.
Western Europe go for that 20" profile in droves and the clearance isn't there, west Europe will just stick to hubs and claim it's an overpriced gimmic.

I think it will do good in north Europe, but fall short for S/W

How did you find it on hub gears?
My understand was that it only works well on a nuivinci, this which spaces out the price point to an unmatched ball park (high components with mid grade electronics) and isn't great considering that's what the north is looking for.

I think the bike you've used is a great match and the style of riding (throttle on hills) really matches the unit.
Bag is a great match, as is the frame colour to the hub :mrgreen:
Endless Spirit.

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Re: New Bafang Crank-drives

Post by jateureka » Jul 08 2013 3:33pm

Is the bottom bracket able to be serviced / replaced with standard off-the-shelf bicycle parts or is it a special item only available from Bafang?
E-bikes: Bafang 8FUN; Mac; Ezee; FreeGo; Aprilia 7s LiPo; eLation V2; TerraTrike recumbent
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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 3:37pm

DIY_turbo wrote:
When we took delivery in March and began to use it as an everyday bike, it rapidly became the favorite bike in the stable. The most frequent description is that it is transparent - you forget it is there and only remember when the battery quits while going up a hill.
Hi greenpark - nice assesment of the Bafang

Does the small heat up fast?

How does the controller react to the PAS ?

Thanks
No heating noticed
The two (controller and PAS) are built in. There is a slight delay in pedalling before it kicks in, and a slight delay when stop pedalling. The Thumb Throttle allows instant, and the brake allows instant cut off. I am told by Bafang that they will be coming out with a torque sensor model later this year. We will probably order one to test.

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greenspark   100 W

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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 4:00pm

t3sla wrote:
How did you find it on hub gears?
My understand was that it only works well on a nuivinci, this which spaces out the price point to an unmatched ball park (high components with mid grade electronics) and isn't great considering that's what the north is looking for.
Once the motor and chain is driving a gear, it works fine with hub gears.

The question of shifting under power is a problem where we used a work around. A Shimano Nexus 3 speed is designed to be shifted when not pedalling. Going up a hill if you find you want to be in a lower gear, without a motor you stop pedalling for a split second, shift and then continue. With the PAS, the motor takes a bit of time to stop supplying power to the chain, thus, if you shift by habit, it won't shift and when the pressure does relieve, it then shifts with a bang... obviously bad for the gears. With a tighter gear hub, say one with seven gears inside, it may be even more problematic, but in any case, it is because the shifting is not being done properly for the design of the motor. The problem is the PAS time delay.

Planning helps... be in the right gear early, or allow time to stop pedalling before shifting. Or, you can slightly goose the ebrake handle, not enough to engage the brake pads, but enough to send the instant cut-off signal to the motor, then shift, then begin to pedal (with the usual delay) or apply the throttle (for immediate power). This is slightly counter-intuitive as one does not brake when wanting more power going up a hill. It also requires a bit more coordination, sort of like learning heel-and-toe driving or turning the handlebar in the opposite direction to effect an emergency avoidance turn.

However, the work-around is also worth looking at: Identify the cable for the ebrake handle that goes to the motor for cutoff, splice in an instant on-off button (press for off) on the handlebar. When shifting press the button to cut off the power. Use the Thumb Throttle to repower instantly. The downside of this is that the waterproof nature of the cable is compromised by the splice.

We have advised Bafang that they need to sort it if they want to capture the internal hub market, especially the aftermarket. There are millions of bikes that would be good candidates for this low-cost, nicely-designed motor.

The best would be that the same instant cut-off that happens with the ebrake is built into a sensor in the pedal. Stop pedalling and the motor instantly stops. Bafang has shown a responsiveness to feedback, so we are optimistic.

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greenspark   100 W

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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 4:01pm

jateureka wrote:Is the bottom bracket able to be serviced / replaced with standard off-the-shelf bicycle parts or is it a special item only available from Bafang?
Don't understand the question. The motor includes the bottom bracket. It is a single unit. The cranks are off the shelf parts however. They supply cranks, but it looks like they are standard.

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greenspark   100 W

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Re: New Bafang Crank-drives

Post by greenspark » Jul 08 2013 4:03pm

t3sla wrote: Western Europe go for that 20" profile in droves and the clearance isn't there, west Europe will just stick to hubs and claim it's an overpriced gimmic.
We plan to install one in a Raleigh 20, a small-wheeled classic. It is not a folder, but we see no problem with it.

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