Electrifying my Dahon Mu Uno

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Jun 10, 2022
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I own a Dahon Mu Uno - which I absolutely love - but am currently looking to electrify it. Now, the upgrade outfit I'm seriously considering using is the Swytchbike one. It looks like a pretty decent bit of kit, but there seems to be one problem - it's designed for the PAS to be fitted on the Left Hand Side. However, for reasons of protection from accidental damage (and because I think it looks better), I would prefer to fit the PAS on the chainwheel side. The manufacturers say this can't be done, because it's designed to be fitted on the LHS. But from reading other posts on Endless Sphere, I just know there's no such word as "can't". I think it's a question of replacing the actual sensor Part No. KT-D12L with KT-D12R. Am I right? or what? Comments please.
 
A picture of the bottom bracket are on the chainwheel side would be helpful. Something that shows the clearance between the chainwheel and BB.
 
Depending on the design of the bracket and the sensor on it, and the place you have to fit it, you may be able to flip the bracket and sensor around, but reverse the direction of the sensor, so that it still senses the correct rotation of the magnets.

Alternately, you may be able to use a completely different sensor, if you know which kind of output that one has.

Most sensors are a simple one-wire type, and simply output a signal when pedals are rotated forward, and no signal in reverse.

Some use two wires, and have different signals depending on direction.

Some of the one wire units do that too.

Some useful info:

https://ebikes.ca/getting-started/pas-options.html
 
Thank you for the responses. Actually, I think I just found out the answer to my own question. In the Swytchbike manual, under Power Pack Settings, in the "PAS Direction" mode you can select "Forwards" or "Backwards", so this would fit in nicely with Amberwolf's suggestion, and hopefully resolve the problem! Thanks again.
 
Further to my previous post, the layout, dimensions and clearance are practically identical on both sides of the bottom bracket, so I can fix the magnet ring either directly onto the chainwheel (epoxy) or in the gap between chainwheel and BB, and locate the sensor on the frame member (with or without spacers).
I intend to mount the Power Pack low down at the front of the bike on a Brompton Block (Dahons have the appropriate fitting point) - a much more stability-friendly location than on the handlebars, and the cable run to the front hub is also shorter. The other cable from the Power Pack can then be run to the PAS along the base of the main frame member, rendering it almost invisible. In my opinion, nothing spoils the appearance of an electricified bicycle more than cables all over the place! And by the way, it's a fairly early Mu Uno with a coaster rear brake, so there is no unsightly rear brake cable.
Since I bought the bike, at least 10 years ago, I have made various small modifications to it, mainly to reduce excess weight. I think the first mod was to remove that unsightly plastic cover on the chain, and replace the silver-coloured chain with something a bit more appropriate. Next, I removed the prop stand and pump-in-the-seatpin, and replaced those ugly ergonomic handlebar grips with some plainer ones, as well as replacing the front brake lever with a dinky BMX-style one. I also took an inch or so off the length of the handlebars. Finally I replaced the lumpy-looking folding pedals with some better-looking ones (which also fold).
Other than that, the only modification I'm considering at the moment is to replace the rear wheel with one based on a Sturmey-Archer 2-speed coaster hub.
 
Reference the final sentence in my previous post, I'm still attempting to source a Sturmey Archer S2C coaster hub in black 116LN 32H. Although they're made in UK, there seems to be a world-wide shortage of them! Can anybody out there help?
 
I just put a Grin kit on my Brompton. I got the Erider torque sensing bottom bracket with it. It works great and the kit doesn't affect the fold. There is also a throttle, which can be helpful for a quick start at a stoplight. I don't see why that kit wouldn't fit on your Dahon. You would just have to have them lace the motor into a 20" wheel instead of a 16" wheel. As a bonus, the Grin Ligo batteries can be taken on a plane for travel.

MTA: I just checked and the front hub of both the Brompton and Dahon Mu Uno have a 74mm O.L.D., so the motor will fit.
 
Re. Grin - it looks OK and the reviews are good. However, price is a consideration, and the price of the Swytchbike setup (including battery) is about 65% of the Grin (without battery) - I would say NO CONTEST! Thanks anyway.
 
Re, My query regarding mounting the PAS on the drive side, I contacted Swytchbike, but I'm afraid they weren't very helpful - their advice seemed to be to install the sensor back to front on the drive side - this definitely didn't sound right to me! I still feel that the "PAS DIRECTION - Forwards/Backwards" option in the Battery Settings is the answer, or alternatively, using a KT-D12R sensor in lieu of the KT-D12L which is probably the one supplied.
By the way, I managed to source a Sturmey Archer S2C hub in the US via Ebay, as advised by RunForTheHills, and that's on its way as I type. Other than that, what's the opinion on the new micro-battery that Swytch are bringing out?
 
I just checked the weight of my Mu Uno, and it comes out at almost exactly 21 pounds, but of course that's before electrification. Obviously, by the time I fit a replacement back wheel with the Sturmey-Archer S2C hub and then later the Swytchbike installation, the weight will increase, but not by much. Anyway, watch this space and prepare to be astounded by some photos.
 
Originally, the bike was a sort of satin black, so then I re-painted it (frame, forks, seatpin,and handlebars)in stealthy matt black - it looked pretty cool like that. Now I'm re-painting some of the other shiny bits (brake calipers, cranks). I intend to upload photos, as soon as I've mastered the technology! Please watch this space.
 
Here's hoping my first attempt to upload a photo goes OK! Fingers crossed!
 

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Of course, these are "before" photos, i.e. before I fit a new wheel with the Sturmey Archer S2C hub or before I buy the Swytchbike installation. I think the completed bike will be pretty cool, totally minimalistic, and also still foldable!
 

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