Technical > Transmission
Installing an electric mid-motor
Andre Jute:
My Bafang 8FUN QSWXK front motor http://coolmainpress.com/BICYCLINGbuildingpedelec1.html has clocked out after four years on the hills of West Cork, so y'all are cordially invited to follow with me the installation of the Bafang 8FUN BBS01 midmotor I've ordered. I'll report on the destruction of the old motor later, and on the installation of the BBS midmotor.
For the moment I just want to say that, when UPS, as per usual, messed up picking up the parcel and lost two whole days (!), my dealer, Eclips Ebikes www.eclipsebikes.com drove to the local depot at 6.30 in the evening to rescue my parcel and then made a 40 mile round trip to the UPS regional depot to put it on the truck.
That's service over and above. You can't ask for more from a dealer. All hail to Eclips Ebikes.
You could ask for a lot more from bloody UPS. Considering that it's almost May, and how the weather this year has gone, UPS has cost me probably 5% of the good cycling weekends in the entire year. A curse on UPS.
More on the death of the QSWXK and the installation of the BBS01 follows in due course.
Andre Jute:
For those who want to perve the new gear I've ordered but not yet received, I bought the full bolt-in kit plus the special optional cutouts for my Magura rim hydraulic brakes.
Bafang 8Fun BBS01 Mid Drive 36V 350W Motor Kit:
http://eclipsebikes.com/images/Bafang350W.jpg
Summary specs at http://eclipsebikes.com/bafang-8fun-bbs01-drive-350w-motor-p-1101.html
The experts here who want know where the motor controller is will delighted to hear it is inside the motor case, cutting down on those wretched wires running around all over the bike.
Bafang 36V/48V BBS01 / BBS02 Hydraulic Brake Sensors:
More info at http://eclipsebikes.com/bafang-36v48v-bbs01-bbs02-hydraulic-brake-sensors-p-1109.html
THE SYSTEM DESCRIBED AND PICTURED DOES NOT FIT THE THORNS WITH ROHLOFF GEARBOXES. MY INSTALLATION IS ON A UTOPIA KRANICH WITH ROHLOFF OEM SLIDERS IN THE FRAME ENDS, NOT AN ECCENTRIC BOTTOM BRACKET. IT WILL HOWEVER FIT THE THORNS WITH STANDARD BOTTOM BRACKETS, LIKE IAN'S SHERPA -- DOWN THE THREAD.
Danneaux:
Hi Andre!
Several questions...
• I notice the unit is approved for off-road use only due to the power output. Do you anticipate any legal hurdles in its use?
• Is the chainring compatible with your Hebie Chainglider? I see the listed chainring is 46t and Chaingliders are not available in that size. Are other chainringss available? The supplied unit appears to be stamped as one unit with the integrated spider....
• I notice the BB is preinstalled. Is there some means to shift the unit laterally for fine chainline adjustment?
• Do you have an idea what the effective Q-factor (tread) will be?
• For those with Rohloff-equipped Thorns, is the fixing plate compatible with an eccentric bottom bracket?
Best,
Dan.
Andre Jute:
SUBSTANTIALLY EDITED 23 JUNE 2015 TO REMOVE SPECULATION AND SUBSTITUTE FACTS LEARNED SINCE THE KIT ARRIVED
--- Quote from: Danneaux on April 24, 2015, 02:48:47 am ---• I notice the unit is approved for off-road use only due to the power output. Do you anticipate any legal hurdles in its use?
--- End quote ---
Jags is cracking his ribs laughing. I'm Irish, man. Scofflawing is my birthright.
--- Quote from: Danneaux on April 24, 2015, 02:48:47 am ---• Is the chainring compatible with your Hebie Chainglider? I see the listed chainring is 46t and Chaingliders are not available in that size. Are other chainringss available? The supplied unit appears to be stamped as one unit with the integrated spider....
--- End quote ---
If you ride in street clothes as I do, it is not only possible but essential to fit a Chainglider to the Bafang BBS. In my first 100km, my trousers were twice caught between the chain and chainring, with the free circular chainguard in the kit adding to the danger of a broken leg or worse rather than preventing it. The kit came with a 46T chainring for which no Chainglider is available, so I ordered a 44T Bafang chainring from EM3ev in China http://em3ev.com/store/index.php?route=product/product&path=46&product_id=193 and a Chainglider https://www.bike-components.de/en/Hebie/Chainglider-350-Vollkettenschutz-Vorderteil-p29665/ from my usual German supplier and fitted them as a soon as they arrived.
Note this about the construction of the BBS mid motor: The chainring is attached to the motor and of course the chain; this is the non-clutched part. The bottom bracket axle sticks through the big hole in the middle of the chainring and the crank is attached to that. If you guys haven't yet studied these midmotors, read these sentences again. The crank is not directly attached to the chainring. The crank is double-clutched and freewheeling. It needs to freewheel or the midmotor will become one monstrous fixie looking for someone's knees to break. The motor itself serves as a spider for the chainring.
To get the narrow tread (trendy talk: "Q factor") beloved of roadies, the chainring is dished. Clearly, the size of the motor limits how small the chainring can go. Here's a high quality 42T chainring from Italy, which is thought to be as small as one can go with the dished, narrow tread setup; you can see how deeply it is dished.
You can already buy chainring adaptors (spiders) to fit the motor (I say again, the chainring is not connected to the crank except indirectly) for chainrings of 104, 110 and 130 PCD, with a choice in some between Californian, French and Australian manufacture. Since the spider needs to move the chain far enough away from the motor to clear the chain and the Chainglider, it will have plenty of metal for fancy pattern cutting. Then you can use any chainring you fancy but...
Chainrings 38T and smaller will very likely not be useful for narrow chainlines. Some people have taken a grinder to the motor casing to use both a low tooth count and a narow chainline; I don't fancy that much!
--- Quote from: Danneaux on April 24, 2015, 02:48:47 am ---• I notice the BB is preinstalled. Is there some means to shift the unit laterally for fine chainline adjustment?
--- End quote ---
The right hand, drive side of the bottom bracket is attached to the motor, the lefthand side is fixed by a normal screw-in bottom bracket fitting, with an over-locknut as well.
Default chainline is 50mm. I arranged a 54mm Rolloff-spec chainline very simply by using spacers, over the bottom bracket unit on the right hand side between the edge of the bottom bracket shell and the motor.
--- Quote from: Danneaux on April 24, 2015, 02:48:47 am ---• Do you have an idea what the effective Q-factor (tread) will be?
--- End quote ---
50mm with the OEM dished chainring.
--- Quote from: Danneaux on April 24, 2015, 02:48:47 am ---• For those with Rohloff-equipped Thorns, is the fixing plate compatible with an eccentric bottom bracket?
--- End quote ---
NO, VERY LIKELY NOT. It is a matter of space. The Bafang BBS hangs on its own integral bottom bracket, which fits standard bottom bracket shells with a clearance outside a standard steel shell for under-bottom bracket cabling of about 12mm. I just don't see enough clearance to allow enough adjustment of chain tension on a standard Thorn Rohloff/EBB installation with the two adjusting bolts under the BB. Sorry.
Danneaux:
--- Quote ---If you guys haven't yet studied these midmotors, read these sentences again. The crank is not directly attached to the chainring. It is clutched, ratcheted, freewheeling, or whatever it is called in bicycles. It needs to freewheel or the midmotor will become one monstrous fixie looking for someone's knees to break. The motor itself serves as a spider for the chainring.
--- End quote ---
Yep, I read the manual: http://www.energiecycles.com/pdf/8FUNmanual.pdf
Looks interesting, and a straightforward installation. Will you be installing it yourself?
Looking forward to your in-use report, Andre.
Best,
Dan.
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