Hub motor vs Mid drive (efficiency)
Hub motor vs Mid drive strictly from an efficiency stand point, ( how far can you go on a charge).
I own and ride both, and from my experience ive noticed that hub drive is about 30% more efficient over all when compared to mid drive assuming all else is the same. wind, grade, tires, weight, assist amount, etc, etc.
however, ive seen many posts and videos of people claiming that mid drive is both more powerful and more efficient. interestingly however, they never back their claims with any real scientific testing or real world examples. just abunch of butt-dynos and % screen readers, ( and we all know how accurate % read outs are on e-mtb's).
As an engineer, i have thought about this extensively. most hub motors have around a 9 to 1 reduction ratio, and the power goes straight into the wheel. while with mid drive you have around a 30 to 1 reduction ratio + the bikes drive train. so you should have significantly more power loss with a mid drive. however the mid drive can take advantage of the bikes
so i plan on doing a very comprehensive test with two bikes , one mid, one hub drive and use identical tires, pressures, weight, power, rider, etc,etc. i want to do 100w, 250w, and 500w at various speeds, grades, and gears, no pedaling just a thumb throttle to take the rider completely out of the equation. a precision watt-meter, gps will give accurate results.
i suspect that on faster
ill post my findings here shortly.
thoughts?
A hub drive has some advantages, like you're not having to
On the bikes I've ridden, weight distribution is noticable with a hubdrive for me - so I'm not sure if you add that in as a factor relating to rideability as a factor with efficiency ? It's a factor which will affect different riders on different terrain in different ways. I think you should also test a two wheel drive setup with smaller motors 
Mabman
E*POWAH Elite World Champion
I also have bikes with hub and mid drives. I far prefer the hub motors for primarily road use and mid drives for off road use. Based on wh/mi seat of the
Neeko DeVinchi
E*POWAH Elite World Champion
ok, numbers are in:
both bikes i used throttle only with a throttle lock to get super consistent wattage's, i used a 200a precision watt meter, and i used GPS to
for this test i used a bbshd mid drive with a 42t front, and the other bike was a hub motor (750w
for the mid drive, H= small rear gear (11t), M= middle
conclusion:
the total system efficiency depends on what ur riding up.
at 250w on slightly hill, a hub drive is approx 62-to-5% more efficient then a mid drive lets just call it 30%
at 100w down hill, a hub drive is 8% more efficient then a mid drive.
motor heat seemed to have made more of a negative impact on the hub motor then the mid drive, probably because the mid drive the motor coils are on the outer part of the can, getting direct cooling, while the hub motor the coils are on the inside of the hub not in direct contact with the outer aluminum can cooling. however, heat didnt make that much difference, about 5%
dirty chain ( caked in sand and mud and sticky grass) ,really surprised me, no
the real world test was a good example of total system efficiency across many usages/ grades. as it appears a hub motor is about 11% more efficient then mid drive. the ride i did is what i would consider a modest average ride through a city, for the average person.
but i bet you if you added more hills into the mix, the mid drive would out
or vice-vera, if you were riding on flat ground, the hub drive would be significantly better.
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Mabman
E*POWAH Elite World Champion
"so end of the day it really is Mid-drive= off road, Hub drive = on road. its really that simple !"
I came to this same conclusion
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