Bafang BBS02 on a BikeE RX recumbent

G

Gus2015

1 mW
Joined
May 25, 2015
Messages
12
Location
Silverton,Oregon USA
In my haste to motorize my BikeE Rx recumbent I failed to recognize the Bafang pedal drive could not replace the BikeE Rx crank due to BikeE Rx crank location, see photo. BikeE Rx right side.png

In email correspondence with California Ebikes I asked whether they felt the Bafang could be installed in the BikeE's mid drive position, they thought it was feasible but suggested I post on this forum for "bike guys" perspectives. A suggestion they made was to consider flipping my front chain drive to the Left, connecting the Left crank to the Bafang's left axle/spindle to engage the freewheel, attaching Right chaindrive to the Right Bafang axle/spindle back to the rear derailleur.

If this is feasible, I'm assuming I need to replace my crank's bottom bracket (Power Pro 7418ST 68mm x 110mm) to better align with the Bafang axles which are about 155mm.

Suggestions, Insights, perspectives, advice and all the details I have not taken into consideration, will be greatly appreciated.

Gus
Silverton, Oregon
 
StudEbiker has a recent BikeE thread you might look at. I posted a suggestion there on how it might be mounted, if you could make that work on yours. (I don't have one of either here to check).

There's other BikeE threads that might have useful info, too, but I don't have any links handy.
 
I've actually been thinking of how one could make the Bafang drives work with a Bike E RX. Having never had an RX or a Bafang drive in hand to examine closely, I can only work off what I can conjure in my mind. The problem I see with mounting the Bafang midship is that there is o my one chairing on it. So that would be the one that would drive the rear wheel, but how do you connect the front chairing of the RX to the Bafang. I don't see an easy way to do that.
 
StudEbiker, thanks for your reply and thank you amberwolf for the Bike E links.

I'm considering connecting the front chainring by moving it over to the left side of the BikeE RX, similar to how some tandems connect to multiple drives. To do this I'm not sure if it would be as easy as installing my Right crank on the Left side, connecting that chain to the bafang left axle, then connecting the bafang Right chaindrive to my rear derailleur. I've stopped at a couple of bike shops to get their perspectives, one said it could work in theory but wondered if the threading on the pedals would cause either pedal to loosen or come off.

The other hurdle is lining up the chain rings. My front BB is about 110mm and the bafang is around 155mm. The widest square tapered BB cartridge I can find is 127mm and I'm not sure if that is workable.

I'm wondering if I need to find a tandem bottom bracket with a Left drive or is that not a problem. I'm also wondering if Fatbikes offer wider BBs that I could use to align the chainrings.
 
I think you could make the tandem timing crank idea work. It sounds like you have thought this through pretty well in regards to chainline on the timing crank.

I don't think you will be able to find an appropriate sealed cartridge bottom bracket with a spindle long enough to align the chainwheels on the left. You can find an old cup and cone style bottom bracket and then your options open up. Those spindles are available in varying lengths, but more importantly they are asymmetrical. They were designed to get the chainwheels far enough away from the frame that they wouldn't hit. The nice thing is that the spindle doesn't care which way it goes in, so you can put the longer side on the left with no problem. It's still going to be tricky to find the right spindle length. You might try the Cyclone USA site. I see thatt they have an extra long Square Taper spindle made to clear mid-drive motors. If you could get the specs for it you might find that it's just what you are looking for.

For the crankset I would recommend getting a proper tandem captain crankset. It is reallly just like a standard single ring crankest, but the threading is the other way, so the chainwheel crank has a LH thread (and the non-drive arm is RH) which allows you to use it without having the pedals come off. Alternately, if you have a good bike shop around you may be able to have them replace the threads on your cranks with steel repair threads which would essentially make your cranks into timing cranks/left side drive. If you don't want to go through the hassle of all that the only other option for riding this way without the pedals falling off is to permanently glue them, or weld them to the cranks.
 
Thanks for the encouragement jtrops and the cup and cone suggestion and Cyclone USA site. I'm going to wait on "proper captain's crankset" until I'm sure this works, I appreciate your insights.
 
Getting closer in my quest to get the BikeRX Bafanged. Just waiting for the longer spindle from Cyclone-USA.com. I was a little hesitant to order from Cyclone because all the browser said it was "not secure", but since they offered a PayPal option I felt "secure". After the order was placed I received a message from Jim Olsen at Cyclone. He informed me that Cyclone now offers a BB cartridge with the longer spindle for the same price as the spindle alone. Although they do not the cartridge listed yet on their site, he sent pictures:

Jim said they were updating their catalog and their site - If you are interested here is how to reach Jim Jim.Olsen@Cyclone-USA.com
 
That cartridge "may" work. The important dimension will be if the left side is long enough to match the Bafang left side. The problem with a cartridge is that it only goes in one way, you can't flip it around to get the longer extension on the left. With a bare spindle in a Cup/Cone bottom bracket you can flip the spindle around to put the longer end on the left.
 
The BB cartridge from Jim Olsen at Cyclone-USA works perfect and aligns nicely with the Bafang. Because I flipped my crank chain to the left to connect with the Bafang free wheel I ended up with a chain tension issue. I had been using SRAM 9 speed chain on the right side to connect to my 9 speed derailleur. When I attempted to use the same SRAM 9 speed chain on the, now single speed, left chain drive I couldn't keep the chain on. Because the SRAM uses their special gold connector I was limited to where I could break the chain. It was either too loose or too tight. The solution was switching to a single speed chain, which allowed using a half link to provide the right fit. Now I am waiting for a speedometer extension cable, the stock speedo cable is too short to allow me to line up the spoke magnet and sensor. I am able to ride but I get error 21 (speedometer) after about a minute, so I am stuck at the lowest assist level. Will post some finished pictures when/if I'm ever finished.

Gus
 
I have been doing short test runs in my neighborhood and except for needing to order a 3 pin speedometer extension the bike has performed well, until today. My right pedal fell off and when I checked the left, it too was starting to unthread. I was planning on changing out pedals anyway so when I put on the replacements I used some Blue loctite. Hopefully that solves the unthreading, otherwise I need a left drive crank. Any suggestion for links to tandem cranks ?
 
It's great to see that it's all working! Too bad about the pedals falling off, not that it wasn't predicted :wink:

I think you may need something a bit stronger than blue loctite if you want to keep the existing cranks. Probably the Red (permanent) version. The mechanical precession that causes the pedals to loosen is a pretty powerful force to resist. Blue may work, but I have my doubts.

The Sugino XD tandem cranks are available individually. You should be able to pick up a left one (w/110bcd spider) for around $35, and a right one (w/no spider) for around $25. If you can use your existing chainring and chainring bolts it will set you back $60 or so for the new cranks. If your chainring has a different bolt circle, and if your bolts aren't for a single ring you will have to adjust the price upwards.

You may get lucky and find a decent used set on Ebay, or even Craigslist.

it may also be worth it to call around and see if any of your local bike shops can convert them with steel replacement threads. That may end up cheaper, and if done right it can be a lasting solution.
 
Well, my plan to venture out with my blue loctite pedals quickly interrupted today. I engaged the thumb throttle to get me up the brief incline in my driveway and the motor stopped. No error message on the 961 display, the usual battery information, nothing indicating anything wrong. The bike pedals fine w/o motor, free wheels ok, but no pedal assist or thumb throttle action. Turning off everything did nothing. The motor was "on" less than a few seconds, any ideas ?
 
Possibly overloaded the controller board inside the motor?
 
Replace it. You could probably get one pretty quickly from Lectric Cycles here in Tempe, AZ. Or ebay or other supplier.
 
Thanks for the suggestion, however if the controller failed under that very brief amount of stress, I'm not sure I would ever trust the Bafang. Are there external controller options that are more robust ?
 
Maybe you just ended up with a faulty component somewhere? Checked all your connections? Check the fuse in the battery?

I do know that Lectric, using their dealer software, does lower the maximum amp draw from their higher wattage kits so as to prevent controllers from burning up if someone blasts the throttle a few too many times.
 
Bad controller verified today, which is very disappointing since I never really stressed the motor - from my perspective, basically just riding around my neighborhood. Now, what to do, the vendor -elifebike, whom I bought the motor from, suggested I ship the controller to them, they will send back to Bafang factory for repair, then I pay for shipping back to me - estimating $25 each way for a total of $50 and a leap of faith that the next controller they send will be more reliable/robust.

Other choices that I am aware of is Lectric cycle's http://www.lectriccycles.com/replacement-controller-for-mid-drive/ , EM3V http://em3ev.com/store/index.php?route=product/product&path=46&product_id=188 but EM3V disclaimer is not very reassuring:
"...-If after fitting a new controller, the kit does not work as normal, stop and do some further checks. Please do not assume that we supplied a faulty controller because after you connected it, it made some funny noises, then stopped working after a short time. It is suggested that you at least do a visual inspection of the motor structure (opposite side of housing to the controller), looking for signs of overheating. A replacement controller will not fix burnt out motor windings!..."
Then there is the Lyen external controller http://endless-sphere.com/forums/viewtopic.php?f=31&t=19587 which is very intriguing because it removes controller from motor assembly.

I've read good things about Lectric cycle, EM3V and Lyen so I'd be interested in hearing other experiences with any of those three.

Thanks for any insights,

Gus
 
New controller from Lectric Cycle installed yesterday, so today rode around town about 5 miles without incident - except for my inadvertent wheelie. I was at the base of a hill on a fairly busy street from a standing start in the bike lane. Because this is a recumbent with its low center of gravity I need a moving start to get seated and my feet on the pedals. Well I decided the thumb throttle should give me the little boost to get going. Unfortunately the stock thumb throttle is pretty unforgiving and the next thing I know I'm flat on my back with my hands on the handlebars - uff duh ! Other than a sore back and a :oops: , nothing broken on me or the bike. I'm considering replacing the thumb throttle with something that offers slightly more control. Half throttle or full throttle or just a better thumb throttle ? Anyone else have issues with the Bafang thumb throttle ?
 
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