Best motor type for cargo bike?

S

Swe

100 W
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Aug 11, 2014
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Stockholm, Sweden
Hi,

Updated information in post written 2017-02-10 so skip my first post.



I am planning to buy a 3-wheel cargo bike, se link below (link to the cheapest one, maybe I will buy another). I will use it together with my two small children, maybe a grown up in there also, to the beach and other trips. So speed is not so important.

http://www.cargobike.se/produkt/Classic-Cargobike

I want to add motor to this, but not sure what motor I should use? A Bafang BBS02 or a hub motor like DD leafbike? I have read somewhere that it would be too much force to use BBS02. But the negative with hub motor is that I need to change the gears, because often when you buy the cheap cargo bikes you get internal gears in the wheel, and you loose them if you change to hub motor wheel.

It is a lot of short but steep hills here. My earlier experiance with motors is geared 250W and 500W hub motors (running on 500W och 1000W). Perhaps geared one is the best instead of DD? Dont like the sound of them though when runnig close to 1000W. At first I was thinking of sharing my 48V 11.6Ah battery with the e-bike and perhaps build a bigger battery later.


So the main point is, what motor type is best on those bikes?



Edit: And a negative thing I read about hub motors compared to mid-drive is that they are weakest on low rpm (low speed in a steep hill).
 
Swe said:
Edit: And a negative thing I read about hub motors compared to mid-drive is that they are weakest on low rpm (low speed in a steep hill).
Click to expand...
Not weakest, just any motor at full power but lower rpm than it's max for that power is not as efficient and creates more waste heat.
 
Hi Swe, If I was you I would likely either spring for a simple geared hub motor conversion kit (like an EZEE, bafang) or a mid drive conversion kit. A geared hub will likely be perfect for a majority of your riding and you will still be able to get up the short and steep sections in a low pedal gear and a ~500-1000 watt system. We use a direct drive hub motor on our cargo bike for reliability, low noise with sine wave controller and ability to have regenerative braking but it sounds like low end torque and carrying another adult plus some kids could mandate gear reduction via geared hub or mid drive.
 
That type of cargo bike often presents a few problems to solve before you can electrify it.

Like you said, you often have an IGH, or at least a coaster brake type hub back there. So you can lose both brakes and shifting when you go to a hub motor.

but put a typical mid drive on it, and you still lose brakes, because backpedaling now just freewheels.

Once you sort out what to do about these things, then you can decide what to do. Converting to disc brakes in the rear by welding on a disc mount is ideal if the frame is steel. If not, you'd need to explore a caliper rear brake.

Then I'd also convert to derailleur gear. Because of the way the handlebars swing, it won't be easy to put all these controls on the steering bar.

If you don't already have the trike, you might consider a re think of the type of cargo hauler.

http://www.cargobike.se/produkt/TrioBike-Mono
 
dogman dan said:
That type of cargo bike often presents a few problems to solve before you can electrify it.

Like you said, you often have an IGH, or at least a coaster brake type hub back there. So you can lose both brakes and shifting when you go to a hub motor.

but put a typical mid drive on it, and you still lose brakes, because backpedaling now just freewheels.

Once you sort out what to do about these things, then you can decide what to do. Converting to disc brakes in the rear by welding on a disc mount is ideal if the frame is steel. If not, you'd need to explore a caliper rear brake.

Then I'd also convert to derailleur gear. Because of the way the handlebars swing, it won't be easy to put all these controls on the steering bar.

If you don't already have the trike, you might consider a re think of the type of cargo hauler.

http://www.cargobike.se/produkt/TrioBike-Mono
Click to expand...

I dont understand why I will loose the coaster brake if I use mid drive motor? The brake is in the rear wheel so it should not matter if I use mid drive?

Maybe if I use regen on a DD motor a caliper rear brake will enough, if there is no mount for disc brakes... I will not be able to fix any welding.
Most often I will not have any adults sitting in it, probably too small anyway, and if I have it will only be for shorter trips.

Why do you recommend that bike type, because of the steering bar?
 
I think I'd just get a big trailer instead and then use a regular bike that you can do whatever you want to it. But I wouldn't worry about brakes. That cargo bike has dual front disc brakes. A slow wind dd motor with regen or ebs will stop it fine.
 
Swe said:
I dont understand why I will loose the coaster brake if I use mid drive motor? The brake is in the rear wheel so it should not matter if I use mid drive?
Click to expand...

A middrive needs to have a double freewheel. Otherwise it would put your legs in curlers while driving with throttle only.
And your bakfiet is listed with a "fotbroms bak", that sounds like foot brake back. With a freewheeling crank you cannot apply any force by pedaling backwards onto a brake system like that. You'd need a brake lever on your handle bar for that.
In addition to that your Nexus 7 IGH would be too weak for a suitable middrive, this bike weights roughly 50kg empty! So you'll need to replace the rear hub like dogman suggested.
At least you have two disk brakes in the front. But it wouldn't hurt to have some kind of brake for the rear wheel though.
 
Buy a different type cargo bike. Look for one with two handbrakes and a regular derailleur.

Then you can do the best solution, a mid drive.
 
I wouldn't buy a three wheel cargo bike.
They are unstable at speed and they constantly lean over with the camber of the road.
I have done over 3000km with my two children in my two wheel cargo bike and I love it.
I use a 12 turn Mac at about 1300 watts, plenty of power and hill climbing ability.
Here is the build log, also see the link within to Cetma cargo bikes, this is the design I copied.
https://endless-sphere.com/forums/viewtopic.php?f=6&t=41358
 
Small wheel, big tire, big DD hub... That is the way to build a reliable cargo bike. Forget about geared hubs and mid drives, for they are not at their best pulling loads and will require more maintenance.
 
Ok yes I will look for a bike that I dont have to switch everything on, and maybe go on DD. The main reason to have three wheel is bevause my girlfriend does not think she can drive a two wheel. Plus it is a little fun to have like a moped. But two wheel should be eaysirr to avood pot holes on bad roads. Will let her try a two wheel model in a store. In reality I will probably be the one driving almost every time.

http://grålleprodukter.se/sv/fordon/gralle-4-t.html
 
I have been using a Bafang 750W mid drive on a Yuba Mundo for about two years and it has been a positive experience. Most of the weight limitation on hub drives at the rear limit you to 200 lbs. The 14mm rear axle on a Yuba holds 400lbs, which I find more suitable for heavier loads. I have carried sacks of concrete, full grocery shops, bales of mulch, coolers, propane canisters, you name it. This is a do all machine and still allows me plenty of comfort with Schwalbe Big Apple tires (rated in the EU for electric bikes at 50KPH) at 35 PSI for a plush ride. I know the bakfeits and such are gaining popularity in the states, but they are too wide and not maneuverable enough for my taste.
 
Cargo and hills. A mid drive seems the only solution. DD the worst as it has the least guts. I was looking at the 3000w un-pedalable 9kg DD group buy motor and it has 80nm while my 500w bpm on 500w controller has over 100nm. Obviously gears are everything for outright grunt and a mid drive has the most. Enough to climb anything really. If you don't fall off the back.
 
Definitely, a trike with a more normal drive train. Standard bottom bracket, rear derailleur,,,, then put a mid dive on it for the best possible results.

If you end up going with a one wheel up front type trike, it may still be possible to mid drive it if you have a suitable bb on the frame. But if not, a low rpm DD up front with 48v (1000w) will do well too.
 
I've just electrified the front wheels on my Bakfiets.nl trike:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=73582
That's allowed me to retain my rear hub gear and standard roller brakes. As you can see there are a few teething problems.

I wouldn't worry about speed concerns when cornering, it takes practice but it's just a matter of handling. I've never had a tip over due to cornering. If I were you and looking at a new trike, I'd go for the bakfiets which has the electric assist factory installed (it looks like they've recently switched from front hub to mid-drive). It's not cheap but there's a fair risk at the price you're looking at that you're buying a cheap Chinese import that will rust through in a couple of years.
 
I have a nihola trike with 36v 500w bafang mid-drive. The business (although wish I'd put in 750w). I use it in the UK (where legal limit is 250w or so for a trike). I have v brakes on rear and drum brakes on front. It shunts me and my 4 kids uphill. I've tried tons of cargo bikes, 2 and 3 wheel. 3 wheels best if you have a partner who is not used to cycling that kind of weight when it comes to a stop on 3 wheels. If you've space for 3 wheels then keep the 2 wheeler for when you're on your own.
 
Now I have decided to buy a two wheel "copy" och bakfiets.nl called Milano. A cheaper version of their original. Upgraded to disc brakes in the front wheel. 7-speed.

https://www.flyingdutchman.bike/our-bikes/bakfiets/milano-bakfiets/

Now I am thinking of a front motor. The front wheel is 20 inch. Main priority is hill climbing. Sure speed is fun if possible when I drive alone but defeating my steep hills with two kids is most important. I was thinking that 1000W is max power I should have?

Does it matter if I choose DD or geared?

My experience is that I probably will never pedal without power anyway. And I like the silence of the DD. But can they compete with a geared MAC or similair at 1000W?

I mid drive will also fit but I want to keep it cheap and simple.
 
Good choice on the Bakfiets over the Trike. I test rode them both and whilst the trike felt best to load the kids up and park, it didn't take much riding to realize they were awful to pedal around on.
I love our Cargo Bike, It's the best money I've spent and I rode for years before finally the kids got so heavy that I needed to add the motor.

I wrestled with the electric conversion system too, and in the end went with a 20" font hub, rather than the Mid-drive.
If I was buying it new I would have gone for the Bosch or Shimano system, but as a retro-fit, the front wheel was just easiest and gets me up hills just fine as long as I add keep peddling and work the gears.

This is the kit I installed:
http://dillengerelectricbikes.com.a...bike-kit-samsung-power-13ah-by-dillenger.html
 
I like the Cyclone3000 because of the planetary gears, see my build job:
https://endless-sphere.com/forums/viewtopic.php?f=1&t=97335&p=1425730#p1425730

cycletruck%2Bwith%2Bcyclone%2B3000.JPG
 
"but put a typical mid drive on it, and you still lose brakes, because backpedaling now just freewheels"

There is one solution for a coaster brake mid drive system:

https://www.aliexpress.com/item/Coaster-Brake-Torque-Sensor-Tongsheng-Tsdz2-Ebike-Kit-Conversion-DIY-Mid-Motor-36v-250w-350w-Electric/32843275113.html

Not a bit system overall either if not too much is asked of it. The torque sensing and throttle option are nice options also. A huge thread over on the non hub drive section about the TSDZ2.
 
Bigwheel said:
"but put a typical mid drive on it, and you still lose brakes, because backpedaling now just freewheels"

There is one solution for a coaster brake mid drive system:

https://www.aliexpress.com/item/Coaster-Brake-Torque-Sensor-Tongsheng-Tsdz2-Ebike-Kit-Conversion-DIY-Mid-Motor-36v-250w-350w-Electric/32843275113.html

Not a bad system overall either if not too much is asked of it. The torque sensing and throttle option are nice options also. A huge thread over on the non hub drive section about the TSDZ2.
Click to expand...
 
Cyclone 3kw is nice, though its not silent because of the gears but it will easily climb a 20% with 375lbs for 150m from a standstill. I tried it a few times and it was marvelous in that way, but i disliked the sound of the gears.

Cyclone TW also makes higher wattage motors that may interest you. I remember seeing a 10kw motor or it may have been an 8kw motor. There is also Golden Motor that sells powerful motors, but all those will start deforming a simple bicycle.
 
My gears are so quiet that walkers on bike trail do not hear it. They do hear the motor if I am moving fast enough.


This sounds like a good application for a drum brake hub in the rear. But only if you can get one made for a tandem [stronger bearings].

Does not a hub motor large enough for this job require a larger battery pack??? I really like using a very low gear reduction [20:1] for slow steep hill climbing. It uses less than half the power than climbing the same hill in a high gear. Then a faster gear for most other road work [11:1].... this is with a 6 to 1 reduction in the planetary gears. The new Cyclone mini has an even bigger planetary gear reduction.

I drove my bike up the short hill up to my house with two arm loads of fire wood in my trailer, while in the high gear drawing about 1400watts then in the low gear drawing only 600watts [Same low speed]. I live in the pacific NW where hills are steep and allover the place. So I did a lot of research and engineering.

my battery is very small, only 13.5Ah I really need one that is more than twice but I am not hot rodder. Batteries cost too much for me.

It is intirely possible to mount a cyclone motor in the middle of the frame, even if you need to move the drive axle back 6 to 12 inches. Really bike builders need to think about making more room behind the seat for a mid-mount-motor. Get a custom frame builder to alter your bike's frame.

Then I was thinking how builders should also make a three speed crank set behind the seat tube, so that it would be easy to do what I did; build a tripple crank with two forward gears [40t and 32t] with Lunacycle's heavy duty chainwheels.
If you live in Europe you may need an even bigger gear reduction to make-up for the lack of power alowed, but maybe the laws have changed?

triple%2Bcrank%2Bwith%2Bluna%2527s%2BHD%2Bchainwheels.JPG
 
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