Hi Miles
Sorry, I somehow missed your post (not used to such a responsive forum!

) - my last post was not a response to yours, but just some more info thrown in for good measure...
Yes, I find those figures on the chinese site somewhat confusing too; the torque curve (under product/parameter on that site) only shows up to 20 Nm, and may be a little on the "optimistic" side (seems to show peak efficiency at just over 80%) but the efficiency at peak power reads as actually a little over 75% - if this is a true and accurate figure, or even close to one, could it not be accounted for by virtue of the peak power being fed to the motor at close to its optimum speed (which, from the same curve, seems to occur at a disproportionately high speed compared to e.g. crystalyte as I said - 180rpm on a motor rated at 190prm, or in 26" wheel 13.4mph approx when motor limit is about 14-15mph) or by an efficiency due to the high gear-reduction, or a combination of both?
I found some posts, seemingly from the makers of these motors, on a partially recovered visforvoltage thread (you get the picture...!) which read:
"Power and Torque are direct proportion relation.So more power means more torque.But there is another important variant----time. Time and Torque are inverse relation.
And that's why we say our motor is very powerful.It is decelerated from the very hign speed of 3000 round and with a very high proportion of 12.5:1.
12.5:1 is the top proportion in China engines(as I don't know much about other high speed motor all over the world).This quite short time makes motor getting a big torque in a split second.
And we should observe the curve to find how it works when you need a big torque.Please find the curve on our website.
You can find on the loading of 20N.m,the efficiency of tongxin motor is still in 75%.And another data,tongxin moto will stop working when it loaded with 35N.m. In short,the high efficiency keep you feeling comfortable when you need a big torque like big loading or going uphills.
This small shape is not just for looking."
From the said torque curve on their website, the peak power occurs at just below 20Nm torque (about 18-19Nm) and so at a
higher efficiency and speed, so if its accurate that efficiency is 75% at 20Nm, then it must be>75% at peak power???!!!
All this assumes, as I say, the accuracy of the given torque curve, but it seems plausible/possible to my, perhaps somewhat naive, sense of mechanics
And yes, Tony Castles would, as far as I know, be the best person to answer questions on the nano motor - unless others have similar experience of them.
My aim is to try to understand how these different hub motors compare in all areas of performance - speed,torque,peak power output and at what speed etc. and so make a fully informed choice on a motor/bike suited to my needs & pocket
