# [EVDL] Front hub motor versus rear hub motor for an e-bike



## EVDL List (Jul 27, 2007)

I have a Dahon 20" folding bike with a BIONx 350 watt motor which works
very well. However, I never use the pedal assist (activated by torque
sensors): instead I simply press the throttle and then pedal in a relaxed
way, in high gear (I never change gear) even up 13% grade hills. I get much
better performance this way and don't experience the odd pulses of power you
get with torque sensors.

Since I never use the pedal assist, I am wondering if there is any
significant advantage to rear-wheel hub motors versus front-wheel hub
motors? It would seem that it would be much easier to add a front hub motor
to a bike than a rear hub motor, so I wonder if the rear hub provides any
special advantage in traction?

Thanks for any opinions on this matter,

-- 
Larry Gales
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## EVDL List (Jul 27, 2007)

Front hub is a much easier install than a rear hub, as
you need to deal with the chain sprockets for the pedaling
on the rear hub.
There are motor kits which have a bracket to suspend the
motor next to the bike and drive a sprocket that is clamped
to the spokes of the rear wheel, so you can convert virtually
any bike to electric.

Drawback of front hub motor is riding on loose/slippery surfaces
as the front tends to break away and since it is your steered
wheel, this makes for an interesting ride. Not everyone likes
interesting.
For example, I enjoy the challenge of riding through a thin layer
of loose sand in a corner of a road and feel the bike trying to
go different ways, for which I must compensate.
My wife will avoid it and if she can't, stop and walk until she
is beyond it.

Hope this clarifies,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Larry Gales
Sent: Friday, May 27, 2011 9:03 PM
To: SEVA; Electric Vehicle Discussion List
Subject: [EVDL] Front hub motor versus rear hub motor for an e-bike

I have a Dahon 20" folding bike with a BIONx 350 watt motor which works
very well. However, I never use the pedal assist (activated by torque
sensors): instead I simply press the throttle and then pedal in a
relaxed way, in high gear (I never change gear) even up 13% grade hills.
I get much better performance this way and don't experience the odd
pulses of power you get with torque sensors.

Since I never use the pedal assist, I am wondering if there is any
significant advantage to rear-wheel hub motors versus front-wheel hub
motors? It would seem that it would be much easier to add a front hub
motor to a bike than a rear hub motor, so I wonder if the rear hub
provides any special advantage in traction?

Thanks for any opinions on this matter,

--
Larry Gales
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|
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| Moratorium on drag racing discussion is in effect.
| Please take those discussions elsewhere. Thanks.
|
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| Multiple-address or CCed messages may be rejected.
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## EVDL List (Jul 27, 2007)

Hi Larry,

On the folding bikes, I've installed Bionx systems on the rear wheel. Mostly on Brompton folding bikes.

It is a bit more work. But I prefer rear hub mounted motors.

WIth Long wheelbase bikes traction can become an issue if the wheel is mounted up front. I've worked on several recumbant and semi recumbant bikes with the hubmotor mounted up front and there have been traction problems. Especially starting out on hills. It's really bad starting out on wet roads.

But a typical 26 inch Mountain bike isn't a problem. It's easier to mount the hubmotor up front. Just be careful. You want to avoid aluminum forks. You want a good heavy steel fork for the hubmotor or make sure the dropouts are heavy duty.

As far as the rear wheel, you don't want to go all out and get a big hi-tourque hubmotor on a small wheeled 20 inch bike, unless you have wheelie bars. 

I did one with a hi-tourque Heinzmann motor on the rear. I think it was 500 watts on a 20 inch wheel. If you pulled back on the throttle too fast the bike would flip back. It's good to keep the battery mounted mid-frame on a bike like that. 

But the Bionx systems are pretty good on the rear wheel. I've never popped a wheelie with one. I've done both rear and front mounted hub motors on the Brompton bikes.

Chip




> [email protected] wrote:
> 
> > Message: 15
> > Date: Fri, 27 May 2011 21:03:08 -0700
> ...


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## EVDL List (Jul 27, 2007)

Thanks fore your quick reply. I was wondering about the affects of traction
since most of the weight is on the rear wheel, but I had not considered the
affects on steering.

-- Larry



> Cor van de Water <[email protected]>wrote:
> 
> > Front hub is a much easier install than a rear hub, as
> > you need to deal with the chain sprockets for the pedaling
> ...


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## EVDL List (Jul 27, 2007)

I can certainly see the poor traction you could get with a long wheel-base
recumbent front hub motor. I also agree that a 500 watt rear hub with a 20
inch wheel could lead to unexpected wheelies. The only problem I have had
with my 350 watt rear hub motor on my 20 inch Dahon Mariner bike is on loose
gravel -- one touch of the throttle, and it fishtails, so I avoid loose
gravel with a small wheel bike.

-- Larry



> Chip Gribben <[email protected]> wrote:
> 
> > Hi Larry,
> >
> ...


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## EVDL List (Jul 27, 2007)

> Larry Gales <[email protected]> wrote:
> 
> > I have a Dahon 20" folding bike with a BIONx 350 watt motor which works
> > very well. However, I never use the pedal assist (activated by torque
> ...


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