# [EVDL] Mid-drive motors versus hub motors for electric bicycles



## EVDL List (Jul 27, 2007)

Hello Larry,

I am using a mountain bike that was converted by Currie Technologies in 
Chatsworth, CA. They use a heavy frame because the 1/2 hp 24 volt motor 
developed so much torque that it could flip you back wards if it was 
lighter.

I purchase it directly from WalMart.com warehouse that was sent directly to 
me fully assembly. The bike weighs 110 lbs and with me on it, it is closer 
to 300 lbs. Cost $295.00

The motor has a internal gear box that has a gear ratio of 3:1 and a 
sprocket gear chain set that has another 3:1 ratio for a total of 9:1 
overall ratio. This gear set is on the rear wheel on the opposite side of 
the bike chain gear set which freewheels when the electric drive is on.

It use a motorcycle type variable motor control grip that also indicates 
battery state of charge lighting up LED's some what the Link-10 does. There 
are two 12 volt 20 ah batteries in a cast aluminum waterproof container that 
mounted vertical be hind the vertical tube that goes to the seat and down to 
the peddles.

I rarely use the peddle drive, because I am either going up or down hills. 
This bike now has be running for 3 years and 8 months on the same battery 
pack. It suppose to have a maximum range of 15 miles at 15 mph, but I have 
never drove it over 5 miles at a time without charging it. If I only drive 
it one mile, it only takes about 15 minutes to charge it.

Roland




----- Original Message ----- 
From: "Larry Gales" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, September 12, 2010 12:56 PM
Subject: [EVDL] Mid-drive motors versus hub motors for electric bicycles


> Most electric bicycles, e-Bikes, are powered by hub motors, either 
> un-geared
> or using planetary
> gears. Even the geared hub motors do not use the bicycle gears, they 
> merely
> use internal gears
> that allow the motor to run at a much higher speed, and thus reduce the 
> size
> and weight of the
> motor while producing more torque than an un-geared hub motor.
>
> But mid-drive motors drive the chain and sprocket directly, and so they 
> can
> use the full range of
> gears provided by most bicycles. It appears to me that mid-drive motors 
> are
> much superior to hub
> motors for e-bikes, but I would like to hear the opinions of others to see
> if I am on the right
> track. Here are what I consider to be the advantages of mid-drive motors:
>
> (1) They use the full set of gears provided by the bicycle and so provide
> the best torque and
> hill climbing ability for a given size motor
>
> (2) They free the wheels from any weight or drag caused by a hub motor
>
> (3) They eliminate any extra work required to change tires or wheels
>
> (4) They keep the center of mass in the middle of the bike
>
> (5) They actually reduce the wear and tear on the main sprocket and chain
> because the
> force is uniform over the sprocket rotation as opposed to foot pressure 
> that
> peaks at
> a few points
>
> (6) The multiplication of the rider's strength is uniform as opposed to 
> the
> jerky forces
> provided by torque sensors.
>
> The only disadvantage that I see is lack of re-generative braking, which
> exists in un-geared hub
> motors.
>
> I came across what looks to me to be an almost perfect e-bike at an
> affordable price at:
> http://www.hightekbikes.com/index.html
> a 350 watt mid-drive motor (the motor drives the chain-wheel so that all 
> the
> bike gears are
> utilized giving it awesome hill climbing ability and the wheels are 
> totally
> free of any extra
> weight or equipment) on an e-bike that weighs only 46 lbs and costs only
> $1600 + sales tax. If
> anyone has an opinion on such a bike I would like to hear it.
>
> Thanks,
>
>
> -- 
> Larry Gales
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: 
> http://lists.sjsu.edu/mailman/private/ev/attachments/20100912/a18a1d13/attachment.html
> _______________________________________________
> | REPLYING: address your message to [email protected] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

You really should talk to Andy Schoenberg about this project. He has 
been building 3 wheeled EVs using bike parts for years. I think he is 
on version number 11 or 12 now. He has built some with hub motors and 
some with chain drive, so he knows from experience what is best for 
what purpose.

http://www.evalbum.com/2200

http://saltlakecity.craigslist.org/mcy/1945546968.html

KJD

http://www.evalbum.com/3175





> Larry Gales wrote:
> 
> > Most electric bicycles, e-Bikes, are powered by hub motors, either
> > un-geared
> ...


----------



## EVDL List (Jul 27, 2007)

It's hard to tell much about this bike just from the photos. As Lee says, 
many integrators use really mediocre components, and you often can't tell 
even up close. 

I guess your best bet is to find someone with experience with the bike. You 
might try posting over at the V Is For Voltage forum, where they have a long 
history with Ebikes.

One thing I'd be a little less than thrilled about with this one is the 
location of the battery. That's usually the heaviest single item on an 
Ebike, and IMO over the rear wheel is not the ideal place from a stability 
and handling standpoint. 

David Roden - Akron, Ohio, USA
EVDL Administrator

= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
EVDL Information: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
Note: mail sent to "evpost" an "etpost" addresses will not 
reach me. To send a private message, please obtain my 
email address from the webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =


_______________________________________________
| REPLYING: address your message to [email protected] only.
| Multiple-address or CCed messages may be rejected.
| UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
| OTHER HELP: http://evdl.org/help/
| OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)
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==


----------



## EVDL List (Jul 27, 2007)

Actually, I am beginning to change my mind about the mid-drive, at least for
small wheel (20")
bikes. I was drawn to the mid-drive because of its inherently high torque
for hill climbing.
But when I look at the hill climbing that I can do with my (direct drive
un-geared)) BIONx 350
watt motor on my 20" wheel bike, and then consider a geared hub motor that
provides much more
torque than my un-geared motor, I suspect that the geared hub motor would be
quite sufficient
even for full size 26" wheels.

In addition, I often now ride the bike in a different way, which I call
"effortless" pedaling.
In this mode I press the throttle, but I also pedal in a very relaxed way
regardless of whether
I am traveling on a flat road or up a steep hill. The effort is similar to
peddling a bike on
a flat smooth road with no wind while cruising at 8-9 MPH. I find that this
increases my range
by 50% over motor-only operation while increasing my hill climbing speed by
at least 20%, and
allowing me to climb hills steeper than motor-only operation allows. This is
a mode of travel
that is ideal for commuting, because it leaves you free of sweat.

I have run some tests with my un-geared hub motor on my 20" wheel bike and
determined its hill
climbing ability by using Google Earth to compute the grade or slope of the
hill. Here are my
results (oh, I weigh about 160 lbs so people would have to adjust these
values for their weight):

(1) For any hill up to a 10 degree slope, motor alone, w/o pedaling, will
propel my to at least
10 MPH. If I employ "effortless" pedaling, I travel at least 12 MPH

(2) For a 12.5 degree hill, the motor alone is not sufficient, but
effortless pedaling will
propel me at about 10.5 MPH

(3) For a REALLY steep hill at 18 degrees (it is frightening to ride DOWN
such a hill), the
motor alone is not sufficient, but if I put the bike in low gear (say gear
2) and pedal with
moderate effort I travel at about 7 MPH. I would estimate the effort to be
about the same as
traveling up a 3 degree slope with no motor assist.

The bottom line, is that if an un geared 350 watt motor can provide such
hill climbing ability,
then a geared hub motor will do much better, so there may be no need for the
extra torque
gained with a mid-drive motor. And this means that 95% of the time, you can
drive in high gear
and so you put very little wear and tear on the chain and sprocket, as the
motor does most of
the work, and you only rarely have to change gears.

Now with 26 inch wheels, you do lose about 30% of the torque, but that
should more than be made
up by switching from an un geared to a geared hub motor . According to this
study:

http://www.ebikes.ca/hubmotors.shtml

a geared Heinzman motor produces 2.3 times the torque of an un-geared motor
of the same power
(but I don't know if that factor is the same for other manufacturers).

So, I think I am in the market for an eBike with a 350 watt geared hub motor

-- Larry



> Evan Tuer <[email protected]> wrote:
> 
> > On Sun, Sep 12, 2010 at 8:56 PM, Larry Gales <[email protected]>
> > wrote:
> ...


----------

