Bafang vs. Nano Tonqxin - torque ?

[kraeuterbutter]

well..
iam so pleased with my Bafang, running on 43Volt
iam meanwhile considering building a second bike with electric motor

criterias like
* free wheel
* light weight

is fullfilled with bout, the bafang and the nano


the nano is even lighter and maybe more quiet


the question is: which has more torque ?!?
yes, it was said here, the Bafang has more power (and more torque?)

however:
iam running the Bafang in a 26" wheel, with Big-Apples, so its more like 26,5" - 27"

the next bike should be a folder, 20" wheels
it should have a very low frame so my - because of car-accident - handicaped father can use it as well..

it does not need to run 40km/h like the Bafang

but it should run up hills AT LEAST as strong, as the Bafang

so: for same torque up the hills with 20" wheels, the nano needs
(26,5" / 20" = ~1,3) less torque than the bafang

the bafang needs to be 1,3times as torquy than the Nano

my question:

how much torque at which cicumstances can the bafang do ?
how much torque can the nano do ?

i have found this:
Hangzhou Zhejiang University Tongxin Electricity Company


in the grafix it looks, like the nano can do up to 20Nm of torque (at 36V and 12,5A)

how much torque can the bafang do ?

so: i want at least the same hill-performance with 20" wheels and nano, as i have now with the Bafang adn 26,5"

 

[frank9755]

I can't answer your question directly but the Tongxin is a powerful motor considering its size.
I know Jeremy has put one in a 20" wheel on his recumbent with success; if you search his old posts you may get more useful info.

 

[kraeuterbutter]

yes, i know his postings..
he went from an heavy crystalite to the super light Nano...

as said:
i want AT LEAST the same torque at hills with the Nano in 20"
as i have now with 26" and Bafang...

with the bafang (21kg bike, 75kg me) the motor can go up hills up to 8-10% without pedaling
11% is not possible (without pedaling)

so: i don´t want less climbing-abilities than that

 

[flecc]

Putting together everything I've read on bikes with Nanos with various wheel sizes with the motor geared for the EU legal speed, 8% should be possible without pedalling for a rider up to 70 kilos, but 10% might not be.

My interpretation is that the Nano is a little less torque capable than the Bafang motor, though better than many others.
.

 

[JohnInStockie]

Possibly a dumb question - what about in an 18" wheel (or even a 16"), would that help the torque?

John

 

[flecc]

Smaller wheels climb better John. The motor torque isn't changed of course, but the gearing of a small wheel to the road is advantageous compared to that of a larger wheel. The 16" wheel Nano-Brompton profits from that, as does my 20" wheel Q bike.

Small wheels aren't as good dynamically for stability though, so there's much to be said for a bike with a 700c front wheel and a 20" rear, the motor in the rear wheel.

I've toyed with the idea of building one like that a few times, but never got round to it. It would have both stability and secure steering with better hill climbing on both motor and pedal power. A sort of 21st century penny-farthing, and good for shorter riders too.
.