Urban Commuter Big Dummy M-Drive Project.

samsavvas

100 W
Joined
Aug 25, 2012
Messages
273
Location
South Australia
Hi Folks,

Today I received my UC Store M-Drive Big Dummy outfit in the mail. I've been waiting for it for a while and I was very pleased to see the box waiting for me when I got home from work! All packed extremely well and transported very rapidly from far away by USPS! I had been a bit anxious about the order a few weeks back as I hadn't heard from Sonny - UCS's proprietor - for a while. Turns out that he had been hit by a drunk driver coming back from the big bike expo held in the States recently (Interbike?) and was sidelined for repairs! When he was back on deck he got things moving again pronto. I understand there may also have been a little more work to do on the front chain tensioner as I had wanted to retain use of my front triple chainset. What he's come up with looks great!

As I believe this may be the first opportunity to document an M-Drive installation on the BD (the first I have heard of anyway) I plan a step-by-step set of posts on the assumption this may be of some interest to others. It won't be much of a technical report I'm afraid. Although I have owned a couple of e-bikes previously (one bought new, one inherited, both by a Canadian outfit whose name - starting with 'B' - I'd prefer to forget), I'm more bike mechanic than electronics whizz! However I'll try to make it as informative and as balanced as I can.

I'll be leaving the electronic bits packed while I sort out my build space. However I have unwrapped the motive unit (MAC 10t + mid drive mount, jack-shaft etc) and I must say that on first inspection the all-black kit is beautifully made, finished and put together. With it comes the controller and throttle, switch etc already connected up. Also a Cycle Analyst and some other extra parts which I'll detail in a further post.

I won't start the build for a couple of weeks as I'm still building new disk wheels and want to clear a space in my rather crowded bike shed. I plan to completely tear down and rebuild the bike and I also want to think hard about where I'm going to mount the controller and CA and how I'm going to install and route all of the cables etc. Initially I'll put the battery (36v/20ah Ping) into a Carradice saddle bag but I'll also give some thought to other alternatives as well.

Believe it or not I do plan this to be as 'stealthy' as possible if that word and the M-Drive/Big Dummy combo aren't a contradiction in terms! At least I don't want too many unnecessary clues as to anything unusual happening with this bike, mainly because where I live power restrictions are (IMHO) plain ridiculous and way below what this outfit is likely to be capable of and what a heavily laden cargo bike could use!

I'll try to post a few pictures in a day or so.

Savvas.
 
Did a bit more work on my mid-drive project on the BD. It's been hard to get to this as I've been finishing off my work commitments to start a spot of leave. I've also been a bit flummoxed by all the plugs, wires etc and have taken a bit of time off to try to understand what goes where etc (the M-Drive kit didn't come with any 'instructions' per se).

The motor has to be removed from the yoke to get proper access to the mounting bolts. Also, as yet I'm uncertain if the front and rear chainlines will be OK. The rear looks about right - a straight edge on the fixed sprocket on the jack shaft more or less lines up with the middle of the rear cassette. Using the same eyeballing method the front looks way off - I suspect a new, much wider BB will be needed (currently it's a narrow 113mm I think). I'm already thinking of alternatives to a front detailleur (Schlumf BB, Rohloff etc)...

Edit: I forgot to mention that the motor yoke is nicely machined and the flats on the motor axle fit in precisely without discernable movement. The axle has also been shortened and end fastening is via recessed screws into internal threads in the axle ends.

I noted that there seemed to be potential for the phase cables to rub against the rotating shell of the motor as they exited from the groove in the axle, so I used a cable tie to keep them in the groove for a little longer. Room for cabling around all those chains will be tight - I'm trying to figure out the best routing.

Sam.

Pics thus far:BDMDE-2.jpg
 

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Made a start on the controller mounting, controls and cabling. I have initially put the 12-fet controller box out of sight underneath the BD's rear rack top. I didn't measure things quite right and the controller interferes with the rear mudguard. I could move it forward a bit but I'm going to try raising the rack top first as I have a plan for fittings that will allow me to carry panniers and use the XtraCycle bags at the same time (or at least have both mounted at the same time). More on this later.

I made up some wire shrouds out of old bike tube to try to protect the wires from the elements where they exit the controller box. They're just glued together from bits of old inner tube and will be tied on with reusable zip ties.

The bar controls Sonny has provided consist of:
- a thumb throttle (my special request) with a red button of unknown function
- a separate 3 position switch (the '3 speed' I believe)
- a separate on/off switch + green button (which I think may be the 'cruise' control).
He also provided a Cycle Analyst-DPS. I have a set of Jones bars I'm trying out so I have plenty of room for all of this. The challenge however is to figure out what is best located where! In particular, because I'm running thumb shifters (old Suntours) it's proving really hard to locate the thumb throttle within easy reaching distance of the right hand grip. The throttle seems quite bulky and I'm wondering if a slimmer type might help things. Hard to know without having something to hand that I can try out. Suggestions from those who have grappled with control issues would be most welcome!

BDMD IC E 2.jpgView attachment 2BDMD IC E 4.jpg
 
Hi Dan,

Thanks for the comment. By 'half twist', are you referring to the thumb or paddle throttle that I have? Or are you referring to a 'grip shift' sort of thing? I'm rather set on using my thumbies, basically because they're simple and bullet proof. What I need to find is a throttle that I can snug in under the shifter's angled cable guide.

Savvas
 
Hi again folks,
For those few who may be interested in this Big Dummy project, I'm happy to tell you that progress has been made and the motor is now up and running. I haven't yet fitted chains or the new, wider BB I think is needed to get the bike on the road. Maybe next week. Getting to this stage took a few weeks due to misunderstandings between myself and the kit's supplier. I couldn't get the kit to run despite the CA powering up. After some problem-solving emails it turned out that the controller had been set at 48V but I had purchased a 36V battery! I did try to re-programme the 12 fet Infineon but it all got a bit beyond me. Very fortunately I managed to purchase from a local e-bike builder (at an excellent price - thanks Terry) a couple of E-zee 48V/10ah packs.

These seem likely to solve several problems.
1. The motor now runs!
2. Between them, the 2 E-zee packs will provide the same capacity (hopefully) as my large Ping and I can probably leave one charging while I use the other (this will be a commuter bike)
3. The packs will permit me to use Grin's new Big Dummy-specific 'twist' mounting plate which will provide a much simpler and neater battery mounting solution on the rear seat stays than the Carradice saddle-bag arrangement I had in mind.
4. The twin batteries actually each came with 2 'standard' full-width Grin mounting plates which I will use on other bikes and which hopefully will save significantly on costs of future projects
5. The E-zee batteries have a built in on-off key-switch and locking mechanism which will save me further effort in making up such safety and security items myself.

Mounting the batteries on top of the seat stays will also make it easier to mount the controller in an accessible but inconspicuous position underneath the stays. I had planned to mount it under the Dummy's rear deck which turned out (like so many of my 'good ideas') to be plain awkward.

So I'm happy and morale has been restored! Now I need some help from ES members please. I understand that fitting 'e-brakes' is recommended, especially for every-day commuter use. I'd appreciate advice as to the options available. The Infineon has an e-brake connector which I assume just requires a make-&-break switch activated by the brake lever arms. I see that Grin sell a cheap Chinese-made set where both levers are linked to the single connector and which use a mechanical 'tactile' switch. The also sell the individual E-zee levers which use magnetic switches (which I'd probably prefer). I'm fitting the bike with new mechanical disk brake wheels and already have excellent new Avid levers that I'd very much like to use. Are there any kits available which would allow me to add simple magnetic switches to these Avid levers and maybe have both levers operating the motor cut-off? I recall that BionX supplied such an 'add on' kit with their motor wheels which you could just glue or zip-tie to your existing levers.

Anything similar available out there?

Thanks,

Sam (Adelaide)
 
Thanks Terry for the link and reminder of the proper term - 'reed switch'. Makes all the difference when you have the proper search term! The link reminds me of the virtues of self reliance. I have a stack of small mega-magnets somewhere. It should be easy enough to make up a couple of e-brake switches.

Update on UC build:
- I've obtained a special Grin Technologies battery rail made for the Big Dummy and EdgeRunner. It's over 40 decrees C today so all I've managed to do is fit the rail to my seat stays and get the battery to clip on. Once I figured out a few clearance issues, the Ezee battery fitted the rail perfectly and is snugly squared away on the stays. Great place for it.
- I have realised that a good principle to follow on ebikes (anticipating that problems always arise) is that things should be accessible! So I'm going to move the controller from under the rear deck to a mounting on a set of bottle bosses behind the rear central strut (forms the hindmost diagonal of the Big Dummy's rear triangle). I've ordered a controller mount from evLab the make this installation neat.
- I've also installed the front chain (runs from chainrings to freewheel on the jack shaft). I have a twin chainring set up with (I think) a 48/38 combination. The chain-run with the 48 is fine but with the smaller ring the chain hits the motor shaft. No good! I was keen to have a lower gear available at the pedals but may have to forego this. I note that for the EdgeRunner, Sonny has gone to a lower jackshaft mount which I presume may allow the front chain to go underneath the motor shaft instead of over. For the time being it seems the bike is an 8 speed only!

Savvas.
 
So glad to find this thread as I'm considering the M-Drive for my Big Dummy. Very keen for any further developments/discoveries/issues/problems before I take the $ leap.

Thanks!
 
NordicNorm said:
So glad to find this thread as I'm considering the M-Drive for my Big Dummy. Very keen for any further developments/discoveries/issues/problems before I take the $ leap.

Thanks!

Hi NordicNorm,

I regret that I haven't continued my posting re. this project. My inactivity has had little to do with the M-Drive kit or it's qualities - more to do with the usual realities of personal circumstance (age, family, work demands etc etc). I will indeed post more here on my completion of my project when I get a bit more time towards the end of the year. I promised the maker I'd post an objective review here - which I have been unable to do thus far. However please feel free to PM me though as I'm happy to chat about the kit which I think has some very +ve characteristics as well as 1 or 2 compromises which are important to understand.

Savvas.
 
Apologies - I've only just noted your query. To the extent that I was able to use it, the Urban Commuter M-Drive ended up working very well and accomplished (I think) everything it set out to do. It was powerful, efficient and allowed easy pedalling when the drive was not in use. However I have now removed it from the bike (Big Dummy) because I found that with the original design of the mounting plates (which I'll call the 'old pattern') I could only utilise a minimum 48 tooth front chain ring. If I tried to change to a smaller ring the pedal section of the top chain run (between the chain ring and the idler shaft) would rub on the motor axle. I believe that M-Drive resolved this issue now by changing over to a 'new pattern' mounting plate that raises the motor axle relative to the idler shaft and thus allows use of small front rings (AND a much bigger motor if desired).

I've tried to purchase a new set of 'new pattern' side plates from Sonny but he has not responded to my queries and his facebook page now indicates that it is 'permanently closed'. I actually bought some suitable aluminium plate and the required bearings etc with the aim of making up a set of plates myself but this has not as yet happened.

So I guess I'd summarise that the design:
- works well
- preserves the bike's integrity as a pedal-powered vehicle
- is probably a bit noisier that a free-wheel hub or mid-drive (exposed freewheels, a bit more chain noise)
- looks more complicated than it really is
- offers great flexibility in terms of motor choice, maintenance etc
- is compromised (in its original form) by restricted use of the front gear system.

It's a shame that the product seems to be no longer made- it would probably work beautifully with a Rohloff! I'll probably reinstate it at some point once I've sorted my bike stable out a bit...

Sam.

https://www.facebook.com/Urban-Comm...yM0cYyWxnodNY1VWcHe4D1r2JCJ_VuxOyg4CIRNYZwWao
 
i asked about it because i'm considering using one of these (an old edgerunner mdrive v1 or 2, don't know if either is comparable to the surly version regarding the issues you had) as the basis for a middrive on the sb cruiser trike (in my signature).

i'll have a number of motor options available, depending on what fits the mdrive, up to a qs203 (which has no axle ends atm, so i have to make a new axle for it or weld ends to the remains it still has.

i will probably have to modify the trike frame and chain drivetrain for this. (presently the pedals only drive the left side, singlespeed freewheel at the wheel, with a 3speed igh just after the pedals, and both rear wheels have big hubmotors) the drive itself won't fit in the frame between pedals and cargo/seatbox, so it would probably have to go *in* the seatbox (which I don't want to do...i'll have to work it out).

but i also still ahve the old crazybike2, which at present doesn't even have wheels on it. used to be 2wd hubmotors, but i'd like to make it functional, would prefer regular wheels (they're stronger, to carry heavy cargo, easier to use various types of rear gear clusters on them, or the option of an igh) and it's got space in teh frame (or can be made to, easily enough) for the mdrive.

anyway, enoguh rambling about my stuff in your thread. ;)
 
Hi Amberwolf,
Don't think I ever replied to your email from 2020 - my apologies! The M-Drive turned out fine if a tiny bit noisy - mainly chain noise. However it's currently sitting in a box waiting for a new bike - I sold my Big Dummy (I needed a smaller bike) but perhaps more significantly, I decided that I didn't like the way the 1st chain run (chain ring to idler shaft) came too close to the motor's axle. This was simply because the axle out was a bit low - I had noted that a later version of the M-drive mounted the motor much higher above the 1st chain run. The axle mount's location on mine essentially meant I couldn't use either a front derailleur nor could I use a chain ring smaller than about 46 tooth (I'm relying on memory here). I did buy some all plate with the intention of making my own copy of the version-2 mounting plates but have never got around to it (I did ask the manufacturer a few times if I could purchase a set of the improved mounting plates but never record a reply).
So the kit will probably stay where it is until I can find a suitable use for it... Sam.
 
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