Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Electric Bikes Here's a place to discuss ebikes, from home grown to high-tech.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-09-09, 01:58 PM   #1
Barrettscv 
Have bike, will travel
Thread Starter
 
Barrettscv's Avatar
 
Join Date: Feb 2006
Location: Edwardsville, Illinois
Bikes: Colnago Nuova Mexico, Eddy Merckx Corsa Extra, Pinarello Gavia, Schwinn Paramount, Motobecane Grand Record, Peugeot PX10, Serotta Nova X, Simoncini Cyclocross Special, Origin8 monstercross, Pedal Force CG2 and CX2
Posts: 10,484
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
(near) zero friction/drag motor assist, does it exist?

Iíve been a bike commuter, up to now I've had a shower at work. This allowed me to travel in bike cloths, shower and change before going to my desk.

I'll be in a new office soon with no shower available. I would like to ride to the office in the morning without working up a heavy sweat by using an electric assist bike.

I would then like to cycle home under human power to get some needed exercise.

Does the mechanical friction or the magnetic field of the electric motor create substantial drag when not in use?

Michael
__________________
When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
Barrettscv is offline   Reply With Quote
Old 05-09-09, 02:11 PM   #2
Allen
Senior Member
 
Join Date: Sep 2005
Bikes:
Posts: 4,751
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
On my Estelle (Heinzmann front hub) I can't tell because the bike is so heavy to begin with. So, I'm going to say not much, probably the same as a dyno hub.

On my Giant Twist (Panasonic BB drive) there is some noticeable drag, say about the same as a bottle generator.
Allen is offline   Reply With Quote
Old 05-09-09, 05:39 PM   #3
15rms
Senior Member
 
15rms's Avatar
 
Join Date: Oct 2007
Bikes:
Posts: 285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Look at the cyclone direct chain drive. I don't believe it creates any drag at all.
15rms is offline   Reply With Quote
Old 05-09-09, 08:26 PM   #4
cerewa
put our Heads Together
 
cerewa's Avatar
 
Join Date: Jun 2003
Location: southeast pennsylvania
Bikes: a mountain bike with a cargo box on the back and aero bars on the front. an old well-worn dahon folding bike
Posts: 3,155
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
The cyclone motor freewheels when not in use (i.e. the motor doesn't turn while the bike's chain and wheels turn). The extra turn in the chain to accomodate the motor's gear will lose you a tiny, tiny amount of energy.

Geared hub motors (like the "bafang" hub motor) will probably create even less drag - all that's added is a freewheel mechanism inside the wheel.

The thing is, even a gearless hub motor (higher drag because the motor spins whenever the bike rolls) doesn't have much effect. Mind you, the extra weight of batteries and motor does make a difference whenever you accelerate or climb a hill.

If you want a workout in the evening, you could just consider the extra drag part of your strength training (and making up for the easy morning) or if you don't think you can handle that, use the motor but only use it on your steepest hill or when you're sure you can't continue on pedal power.
cerewa is offline   Reply With Quote
Old 05-10-09, 05:05 AM   #5
Kingofgreens
Accept no substitutions
 
Kingofgreens's Avatar
 
Join Date: Jan 2009
Location: Wilmington Delaware
Bikes: 2006 Mongoose Wing Elite, BMC 600w brushless rear hub, Crystalyet 40a 36-72v digital controller
Posts: 67
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have a BMC geared brushless rear hub. It completely freewheels. No drag whatsoever & it is supposed to be the among lightest available.
Kingofgreens is offline   Reply With Quote
Old 05-10-09, 06:00 AM   #6
bdi121
Senior Member
 
Join Date: Apr 2009
Bikes:
Posts: 108
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have a front geared brushless hub fitted into my existing bike. Freewheel.

I often feel there's a little friction when taking my thumb off the throttle and pedal. Must be psychological, as I was "pull along" by the motor a moment before.

However, at one time, I wasn't able to use my electric motor for a week (warranty repair on my charger ) , used the bike unassisted and I didn't notice the friction at all.

Warning: In practice, I find myself using the motor rather than pedalling uphill no matter how easy the hill is. My heart rate doesn't increase much. . . . . But my intention is good though
bdi121 is offline   Reply With Quote
Old 05-10-09, 12:12 PM   #7
Barrettscv 
Have bike, will travel
Thread Starter
 
Barrettscv's Avatar
 
Join Date: Feb 2006
Location: Edwardsville, Illinois
Bikes: Colnago Nuova Mexico, Eddy Merckx Corsa Extra, Pinarello Gavia, Schwinn Paramount, Motobecane Grand Record, Peugeot PX10, Serotta Nova X, Simoncini Cyclocross Special, Origin8 monstercross, Pedal Force CG2 and CX2
Posts: 10,484
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Thanks everyone. My commute is flat, so a heavy bike is not a serious issue. I was afraid that I would be driving a generator when the motor was not powered. I don't mind some extra effort, but I did not want a slow commuter over 15 miles. I now see that this is not the case.

Michael
__________________
When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
Barrettscv is offline   Reply With Quote
Old 05-12-09, 03:43 PM   #8
Solar.110mb
Senior Member
 
Solar.110mb's Avatar
 
Join Date: Jul 2008
Location: Michigan, USA
Bikes: Schwinn Izip
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The Currie motors on Schwinn Izips or the Walmart ones that have a separate chain do not drag at all. In fact when I first bought mine I had no battery for a week and went on 20 mile trips with no power, it felt like a regular bike.
Solar.110mb is offline   Reply With Quote
Old 05-13-09, 06:04 AM   #9
gmouchawar
Senior Member
 
Join Date: Mar 2008
Bikes:
Posts: 214
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
All the options above have integrated freewheels somewhere in the system.
I have a Heinzmann brushed hubs on my ebikes and it has a integrated freewheel so it is drag free
if you are going faster than the motor.
The direct drive hub motors will have some drag, which people sometimes call coging.
Good luck,
gmouchawar is offline   Reply With Quote
Old 05-21-09, 06:24 PM   #10
lyen
Lyen
 
lyen's Avatar
 
Join Date: Jul 2007
Location: San Francisco, CA, USA
Bikes: Dahon 2007 Cadenza, 2006 Speed Pro, 2005 Helios SL, 2004 Roo El, Minimoto Electric Bike, USPD Currie Electro Drive Electric Bike, Schwinn Scooter
Posts: 126
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Yes, see the thread below:
Need advice from experienced e-bikers
lyen is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 08:04 AM.