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E-Bike Conversion

Phil Dorney2023-09-11 20:23:08
I have recently completed an e-bike conversion of my tandem using a Bafang BBS02 mid drive kit.  Happy to answer any queries in case someone else is considering it.
Nigel Pigott2023-09-16 18:19:02
I have just fitted a Tongsheng TDSZ2 mid drive to our Lee Cooper tandem. I imagine the process is similar to the Bafang. It was straightforward and I didn't even need to lengthen any cables. I agonised for a while about the difficulty of keeping the cranks in sync, given that the stoker's crank decouples as soon as he or she stops pedalling. I even tried bolting the stoker's timing and drive cranks together (now both on the rh side), until I realised that this completely nullifies the torque effect on the Tongsheng BB axle so you get no assistance. Now I have decoupled them everything is working well and it hardly seems noticeable when the cranks go out of sync. My stoker loves it that she can now stop pedalling whenever she likes, although this of course turns off the motor. I hope this all makes sense. I believe the Bafang has no torque response so I'm not sure how this affects the setup.
Nigel Pigott2023-09-17 08:02:59
What I meant to say but didn't express very clearly was that I foolishly put an M8 bolt through the stoker's rh crank arm into the chainwheel to keep the front and rear cranks in sync, which completely nullified the stoker's input on the torque sensor as the pedalling effort was transferred to the chainwheel rather than the BB axle.
Giles Orton2023-09-25 08:15:37
Hello. Thanks for the offer of advice. May I put the following questions please. I am contemplating electrifying a Circe Helios. The Bafang seems a well established product. How did you decide on that? How does it compare for performance with the Shimano STEPS which Helios offer (bit which as far as I can see cannot be retro-fitted without a whole new frame)? Or with the Heinzmann front hub motor? (I rather  assume it must be beneficial to have the electric power assist the pedals and so gain the benefit of the gearing?) Or with other products? Can you recommend any suppliers, please?