iZip e3 Dash (2018) / Tranzx M16 DIY repair


New Member
Hey all, my e3 Dash mysteriously stopped boosting last week, and Saturday I tried to diagnose/repair it (successfully for now). I did some tweeting about the disassembly if you want to follow along but the important part is probably what's in the picture - that transfers power from the motor to the crank. Sorry I don't have a good picture of the thing assembled, but roughly the thing with all the pawls goes around the shaft part, then that whole thing goes inside the bigger gear, then the small gear also gets mounted on the shaft. The part with the pawls only engages in one direction; when it's engaged both gears turn together, when it's not they just spin freely. Note that it's purely mechanical.

I confirmed that seemed to be the problem, the motor was running but not providing any power. If I turned the big gear by hand, the little gear that drives the crank wasn't turning. So, I took that all apart and you can see a bunch of pawls fell out. I wish I'd have gone a little slower taking it apart to get a good look at the state of it. But, I put the pawls back (which was tricky) and confirmed that it would now "lock up" in one direction so the gears would turn together. I reassembled the whole thing and rode around the block and it works! Although it's noisier than it used to be, I'm not 100% sure I put it back together perfectly (there were a couple washers I should have paid more attention to). I also worry the housing that bearing presses into may have already been damaged (there were some metal shards when I took it apart and I think I know where they broke off from) which may have been the source of the problem, so maybe the whole thing will just break again.

Anyways, not really how I wanted to spend 10 (!) hours on a Saturday. I was surprised not to find any shop manuals or parts diagrams on the net - does anyone know where I might find one? I wrote to iZip, waiting to hear back, but this really should be a thing they just make available. There is one video of someone disassembling one, although not as far as I went. I also asked iZip if they sold parts, I'd feel better about it if they could sell me that whole gear assembly and I could just replace it. Now that i know what I'm doing it'll go way faster ;)

Also kind of amazed that all of the motor torque gets transferred through that thing with the pawls, especially since it's so buried in the motor - seems like that mechanism could have been external to the motor. There's a separate, simpler mechanism that disengages the pedals if you're coasting - I *think* the purpose of this is so the pedals don't drive the motor if you're pedaling faster than the motor is going, but I'm not entirely sure about that.

I took the bike out for a ~10 mile ride, including some steep hills, and it's working ok, but something is still clearly wrong... sometimes it didn't feel like it's providing full boost. I'm worried it will fail again.

I had also filed a support case with izip - I didn't hear from them so I tried again. The second time I got a confirmation email which I didn't get the first time, so I'm not sure what went wrong there... and, they got back to me to say they don't consider the drive unit field serviceable, so they don't provide manuals or internal parts. They do provide replacement motors but only to dealers, and pointed me at a dealer not too far from me, so I guess i'll get in touch with them to see what they say... kinda crappy to have to replace the whole thing, and I'm afraid of the price.

PS: I learned that the circular thing is called a sprag clutch, and it's nice that it kind of works like a freewheel without any clicking.
Finally talked to a shop last week... $880 for a new drive assembly, installed. I didn't ask them about the price without installation because I assume it comes with a warranty I probably won't get if I install it myself, plus they said some programming needs to be done that I probably don't have the ability to do myself. So, I'm not sure if I'm going to do it, I guess even at that price it's cheaper than buying a new bike so I probably should, but it's a lot of money.
I'm like 95% sure all I need is that gear assembly sitting perpendicular between the two halves of the motor casing at the bottom of the photo (that's what's disassembled in my original picture), but they won't sell it to me :(

Have tried here?

sadly this was a comment. “Welcome to the benefits of using a highly proprietary, non-interchangeable system. I say either write it off, or pay the $550 (and then do it again later).”
Last edited: