dilkes

A friend has a cargo trike - 1 wheel at the back and 2 at the front. The rear wheel has a Nexus 7-speed internal hub, so I don't think they should put a hub motor on the rear. Therefore options seem to be (1) a mid-drive or (2) hub motor(s) on the front wheel(s).
Questions:

1. Would a hub motor on just one of the two front wheels work/make sense -- or would it cause the bike to sway to one side?

2. Can a motor be placed in each of the 2 front wheels and both be controlled by the same throttle? Does this make sense?

3. Has anyone done either of the above?

Appreciate any guidance.

The bike is something like this:
Wike Big Box Trike

2old

One front doesn't seem feasible, but I haven't done it. However, it's possible to control two motors with one controller (use a splitter which I haven't done either, but Easy Motion and Oyama have commercial bikes with this feature). Of course, two fronts with two dedicated systems is relatively easy.

CliffordK

I agree. Go with 2 hub motors.

Wire them in parallel, and you'll have the right volts, and just have to get a controller that can handle the amps (sum of the two).

Another option is to go with a "Mid-Drive" motor. Essentially powering your chain. A lot of people like the mid drives, and hopefully your hub can handle it.

I've heard of people using the NuVinci hubs with mid-drive motors with a lot of success.

Rick

If you go with a mid drive that is designed to be an assist that has no throttle than the IGH can handle it. TSDZ2, mini 750W mid-drive with torque sensing

fietsbob

LBS has done Mid Drive conversions to a number of bikes for several years .. most customers Hunters .

Because most of the counties are wooded, timber lands.. And Elk & Deer are in them, and in towns too.

fietsbob

AND Remember 2 front wheels don't go the same distance, when going around a corner...

elizilla 

I just finished adding electric to a Pfiff Primo, which is a reverse trike with a Nexus 7 speed rear, like yours except mine has no cargo box. I think two motors in front is too heavy and too complex. One front motor would handle badly. Also, hub motors depend on really solid forks/dropouts for their axles, you would have a challenge fitting them with the single side attachments you have on the front. They would need some pretty fancy torque arms.

So then I tried to fit a mid drive but my bottom bracket was just not suitable.

Ultimately I installed a hub motor in the rear wheel and let go of the IGH. The one I got is designed for trikes, so it has reverse, which is good to have when your bike is heavy and has such a wide turn radius.

There exists a cargo trike like yours, with electric already on it. It is called the Virtue Schoolbus. You could google it and see what they did. I bet there are reviews that would give you some idea how their choices are working out.

Rick

Yes it has been done. contact Grinn

Rick

Grinn has all of the toys when it comes to electrifying your ride.

dilkes

Thank you for your experience and for the pointer to the Virtue Schoolbus.
Questions
Would you have a link to the motor you used?
When you gave up the IGH did you end up with a single speed bike or did you install a derailleur?
The bike we have has a rear brake activated by pedalling backwards. That would go away if we replace the hub. Did yours have that as well?

Thanks again for the help.

elizilla 

Hello,

The motor I used is this one: https://www.ebikekit.com/collections...ystems-lithium

I contacted the company and they were able to provide that kit with a rear wheel with a freewheel instead of a front wheel. They offered me a choice of freewheels and I chose the one with nine cogs and it did not fit in my bike; they had to send me a seven cog to replace it. Which they did, but it was a hassle. I'm guessing that since you have the same Nexus hub, you have the same space constraints, so, if you do this, get the seven speed. To go with that freewheel I got a seven speed derailleur and shifter; the only ones I could find were inexpensive low end Shimano ones but they are working fine. Important to find a shifter that doesn't tuck in too tightly around the brake mounts, because it will interfere with the throttle switchgear. My shifter is a Shimano Tourney SL-TX30 and the derailleur is Shimano Acera RD-M360. I also had to replace the chain since with the derailleur you need a longer one. And I had to get a shifter cable for a tandem because the bike's crazy geometry needs way more length than a standard bike.

When I installed it I lost the coaster brake, but to me that was a plus because I had determined that I couldn't stand having a coaster brake. I needed a freewheel because I am disabled and have trouble getting my feet onto the pedals - this is also why I chose an upright trike. My bike came with BOTH a rear rim brake and coaster brake so that worked out fine. The motor kit manufacturer offered me a rear wheel with a disc brake mount as well but my bike doesn't support that; maybe yours does.

That kit has a 36V battery which gives a top speed of 15mph. I actually upgraded to a 48V battery which can go 20mph, but this was a waste of money - the trike's handling is hair raising at 10mph; I doubt I will ever get to 15 let alone 20. If I did it again I'd stick with the 36V battery.

If you can squeeze in a mid drive motor you can keep the hub and if you like it, you might prefer to go that way. That Nexus setup is really nice and it would be good to keep it. But whether you can do mid-drive depends on what your frame looks like near the bottom bracket.

Or if you prefer to keep the IGH but want a hub motor there is a hub motor out there with a five speed Sturmey Archer hub: https://www.ebikes.ca/shop/electric-.../tdcm-igh.html I have not tried it, I know nothing, but it is out there. That company (Grin Tech, same ones who did the two-front-motor Catrike Rick posted above) also offers a wide choice of pedal assist arrangements and has a great website explaining them all. You may want to read through their site just to learn more; I found it a wonderful resource.

dilkes

Thanks again for all the feedback and links. I think we'll be going with the same kit. One last question. Did you install a torque arm (or 2) on the rear wheel?