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Old 08-30-08, 01:31 PM   #1
pengyou
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Chain driven electric bikes claims

If you look on the following website:

http://www.cyclone-usa.com/store.php?crn=199

It says " Because it uses the bike's rear gears, this 360w motor will outperform hub motors of equal or larger size."

I know the theory behind this. Is there any proof? Are there any folks out there who have this kind of motor setup on one bike and a hub motor on another?
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Old 08-30-08, 01:44 PM   #2
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I have a panasonic chain drive on my Giant Twist.
We also have a Heinzmann equipped Biria (front hub).

The motor on the twist is a 350w the Heinzmann is a 400.
The Heinzmann has a higher top speed, but the panasonic has a governor that cuts the motor at 16-17 mph.
The difference in torque is astounding. The chain drive is vastly better than the hub motor.

Given the choice I will always pick a chain drive over a hub motor.
The disadvantage to inline drives is motor placement can be difficult.


The Twist/Lite


The Estelle (a Biria rebranded by Heinzmann after they added the hub)
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Old 08-30-08, 02:10 PM   #3
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Power is the ability to move objects through a given space in a given time.

Here on Earth, 1 horsepower is the ability to lift a certain amount of weight (330 pounds), straight up a certain distance (100 feet), in a certain amount of time (1 minute).

1 HP equates to about 740 watts, so a 360 watt motor won't carry you around like a 1,000 watt motor, so when they say "outperform" I'm skeptical, although going through the gears could enable a higher top speed than a hub, depending on voltage and amps being used in the hub.

Given the choice, I'd rather have a 360 watt brushless type hub, for the efficiency, quiet operation and easy installation, than a chain drive. I personally run a 36 volt 750watt hub on one bike, and a 48 volt - 2500 watt 5305 hub, on the other.

I like electric bikes, so if the kit's cheap enough, I'd use it. Batteries are a whole nuther subject.
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Old 08-30-08, 02:32 PM   #4
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The idea for chain driven(or any variable gear ratio) systems is that your electric motor is at its most efficient and most powerful when its spinning at or near its max RPM for the voltage given. So with a geared system, you can achieve max efficiency all through from near zero to max speed. Im not sure but i think that the amount of time it takes to reach the same higher end speed as a non geared system is greater with a lower wattage regardless of gears. Basically the gears only help torque at low speed then the watts are the only thing that matters.
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Old 08-30-08, 03:08 PM   #5
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the easiest way to remember this is to think about how your legs work on a multi-geared bike. In any gear, the muscles are the same strength. Yet, you can vary the gear ratios so your are more optimized for hills or flat ground.

Often, we don't realize that a dc motor is faced with the same physics, because an electric motor torques very well at low speeds.

However, a steep enough hill will exceed the torque capabilities of a motor, and if you have the ability to gear down, you would benefit much like you benefit from your granny gear.
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Old 08-31-08, 09:44 AM   #6
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Well, I have tried both on recumbents. With the Electroportal 500 watt motor (the same motor as Cyclone), I go up my test hill with the same ease as a 1000 watt hub motor. Depending on the gearing, I can get better top speed too. The inline Electroportal weighs about 7 lbs. and the hub motor weighed 15 lbs. The inline motor is more efficient also because it is running near its peak efficiency speed most of the time. Most hub motors are at their most efficient at 11 to 16 mph on the flat. Hub motors aren't really great for very hilly places like where I live. Think about it, would a car work well with only one gear? Which gear would you choose? Now, electric does have a better torque range than the infernal combustion engine but you get my drift.
However, inline motors do have a whine to them when you use them, in traffic you wouldn't notice it but on a trail you do. Hub motors are easy to install and quiet. Inline motors are great on recumbents because they have long chainlines so are easy to install the motors. I don't like the Cyclone because you have to sacrifice the triple crank in front with their system. Now the bike is useless for the steep hills here so I may as well use a hub motor. I did get a freewheeling triple gear from a tandem so I might try that this winter.
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Old 08-31-08, 10:26 AM   #7
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crackerdog, I'm pretty sure that you have this figured out, but I wanted to answer just for my sheer interest in the topic...

Quote:
Originally Posted by crackerdog View Post
hink about it, would a car work well with only one gear?
an electric car would because an electric motor delivers a great deal of torque.

But if you make the motor a bit on the small side, then multiple gear would be necessary.

Back to bicycles....steep hills have a way of making an electric motor on an ebike too small.

The solution?

go for a bigger more that naturally has more torque ( but you'll kill your battery faster)

or

go for multiple gears.

or

go with one gear that is lower, but that will effect your top speed.
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Old 08-31-08, 11:47 AM   #8
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Wonder if anyone here thought about a rear geared hub motor, or a chain drive, either for their hill climbing torque advantage, then a regular hub motor on the front for it's high speed advantage. This might be cool too if they could share common batteries, controllers and maybe even throttle. An A/B switch would select either method of propulsion. The only disadvantage I can see is the added weight of dragging around the unused motor.
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Old 09-01-08, 12:27 AM   #9
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The Aptera electric car has a continuously variable transmission.
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Old 09-01-08, 09:06 AM   #10
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A hub motor has no 'high speed advantage' over chainline motors, so you would just be adding more weight. My problem with just adding a bigger hub motor for hills is the weight. Big hub motors weigh so much it is difficult to lift the bike onto a bus rack lets say. The hub motor has its place because it is easy to install on regular upright bikes and it is quiter than inline.
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Old 09-01-08, 10:22 AM   #11
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Quote:
Originally Posted by Mr York View Post
The Aptera electric car has a continuously variable transmission.
I'm running a NuVinci CVT on that Giant.
As far as internal gear hubs go, I like it as much as I do my Rohloff hubs.
It is the most durable and smooth hub I've ever owned.
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Old 09-01-08, 09:26 PM   #12
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Chain Drive Hub...

First off... Chain drive is better in only 1 place, hilly or mountain areas.
You lose an instant 15% just from the resistance, heat loss etc etc from cranking through a chain driven transmission.

In a hilly area it would be better than a hub motor. But other than that it is far inferior IMHO.

In a flat area which many metro cities are and most of the USA is, a hub motor is far superior.

Not that one is better than the other just each has its place.
THis is one of those conversations where someone says hub is better than chain yada yada..

Each one has its place where is is superior. For the majority of the USA it is a non geared hub motor. But other places where there are many hills etc the chain drive works out much better.
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Old 09-01-08, 09:28 PM   #13
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Quote:
Originally Posted by turoczi View Post
First off... Chain drive is better in only 1 place, hilly or mountain areas.
You lose an instant 15% just from the resistance, heat loss etc etc from cranking through a chain driven transmission.

In a hilly area it would be better than a hub motor. But other than that it is far inferior IMHO.

In a flat area which many metro cities are and most of the USA is, a hub motor is far superior.

Not that one is better than the other just each has its place.
THis is one of those conversations where someone says hub is better than chain yada yada..

Each one has its place where is is superior. For the majority of the USA it is a non geared hub motor. But other places where there are many hills etc the chain drive works out much better.
Two places--hills, hauling heavy loads.
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Old 09-01-08, 11:58 PM   #14
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Of course, Ecospeed (inline motor) won the electric bike race on a race track. Why would you lose 15% because of chain drive? Is a non-motorised bike that inefficient?
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Old 09-02-08, 08:38 AM   #15
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Im resonably certain from reading about chainless bicycles that you only loose about 5% to the chain. granted, the chain will wear out much faster then it normaly would because you are applying so much power to it. There is also the aspect of constantly having to maintain your chain and oil/clean it.

In short, im pretty sure that chain driven is always as efficiant or more efficiant then a gearless hub motor, but it carries with it much more maintainance. I think lowell at one point said he was swaping chains out every 1000 miles. Im not sure how much you will be riding but for me thats something like every two months.
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Old 09-02-08, 09:05 AM   #16
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I'm swapping out chains (due to stretch) about every 3K miles (the Giant is an internal hub--straight chain line).
That is not out of the norm for a regular road bike.

My other (non motorized) internal gear hub bikes are getting new chains every 5k to 8k miles.

The biggest wear on a chain is the offset angle that occurs when using external gears (derailers).
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Old 09-03-08, 12:40 AM   #17
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Originally Posted by crackerdog View Post
Think about it, would a car work well with only one gear? Which gear would you choose?
Gearing is not nearly as necessary with an electric motor as with an internal combustion engine. The torque is maximum at 0 rpm, and the power curve is much flatter:

http://www.teslamotors.com/performan...and_torque.php
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Old 09-03-08, 05:04 PM   #18
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Strictly speaking electric motors deliver maximum torque at CLOSE to zero rpms.

torque = power / angular speed

division by zero is undefined.

Nothing happens until you get 'er movin'
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Old 09-05-08, 09:00 AM   #19
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Quote:
Originally Posted by AllenG View Post
Two places--hills, hauling heavy loads.

Oi!
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Old 09-05-08, 11:22 AM   #20
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Ecospeed.net has some interesting info on their site about this.
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Old 09-05-08, 01:33 PM   #21
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Quote:
Strictly speaking electric motors deliver maximum torque at CLOSE to zero rpms.

torque = power / angular speed

division by zero is undefined.
yes, but check the mathematical limit as speed approaches zero.

Torque and force are related concepts, both of which are valid at speed of zero as well as higher speeds.

Torque wrenches measure torque and are intended to do so primarily when a bolt is not in motion.

If torque did not exist at a speed of zero, toyota priuses would not be able to move uphill from a dead stop, and starter motors would just sit still whenever a person tried to start a car. electric trains (and diesel trains) would be useless.
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Old 09-06-08, 10:09 AM   #22
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just noticed that there is a review of a cyclone motor on endless sphere
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Old 09-08-08, 06:29 AM   #23
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Force does exist at zero rpm.
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Old 09-09-08, 06:17 PM   #24
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at 0 rpm, you can have all the torque in the world, but, no power. Power is a function of torque and speed. At a given torque, hp increases with rpm.

So, even though torque drops with speed, I would think that it drops rather slowly. I doubt that most motors running at 200 rpm make half the torque of one running at 100 rpm.

Therefore, it does stand to reason that a motor going through a chain drive taking advantage of the ability to run higher rpms would outperform a hub motor. As for efficiency, there is some loss through a chain, but, I doubt it is anywhere close to 15 pecent, unless maybe you haven't lubed your chain in 10 years.
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Old 09-11-08, 11:03 AM   #25
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Quote:
Originally Posted by pengyou View Post
It says " Because it uses the bike's rear gears, this 360w motor will outperform hub motors of equal or larger size."

I know the theory behind this. Is there any proof? Are there any folks out there who have this kind of motor setup on one bike and a hub motor on another?
I think I have some proof if you rode my bikes.
I have 2 bikes that use the rear internal gear hubs driven by chains from a motor mounted mid frame.
The Charger bike is one, and my home built Speedmachine is the other.
Check here for pics and specs.
http://www.evalbum.com/1262
I also have an E-bike that uses a rear hub motor to compare.
First of all, most ICE have a horsepower and torque curve that will peak in a certain RPM range.
So using a transmission will let you take advantage of that and give you the best of both worlds, low speed torque and high top end speed. Use a single speed transmission and you get one or the other.
Electric motors on the other hand have very good low speed torque that can be flat across the RPM range.
Given that, its not as necessary to use a gearbox to get good acceleration BUT, you are usually limited in top speed, say 80 MPH (for a car). Also remember that usually a good 3 Ph AC motor used in electric cars are geared down (10:1) and have an top RPM of 10,000. Much more than an ICE.
Crystalite hub motors break down their hubs in speed ranges.
http://www.electricrider.com/crystalyte/index.htm
You get low, mid or high but you can't have it all.
Now comes the transmission.
Since I'm using the existing gearing, I'm not adding anything else except for the motor and gear reduction.
Ecospeed has a good page to read about gearing.
http://www.ecospeed.net/gears.html
I can have my cake and eat it too.
I have the ability to use my motor throughout its RPM range and then up-shift, so I can use the low speed torque and then the high RPM horsepower. Once I run out of RPM, I up shift to use it all over again.
Its the whole reason you use gearing on a bicycle. Just think if you only had one speed, and some bikes do! You have a low gear beach bike that goes maybe 15 MPH max or some of you who ride a single speed track type bike (with brakes!) and have very little low speed torque. Not too good on hills is it!
So in a nutshell, I don't like hub motors. Sure, its an easy way to build your own electric bike, nothing to it actually, just install the hub and wire it. Unlike building my bike, you have to have room for the motor, make mounting plates, figure out the gearing, bearings, freewheels etc, BUT, yes another but, you are not dragging along the motor as you are in a hub that is always turning! Plus it takes more power to rotate that heavy hub. So lots of pros and cons, but the way I see it, well, its the way I built it. And I'm still going to add improvements to my Speedmachine..
Oh BTW, the Charger bike is plenty fast too, even though it only uses a 1/2 horse motor. I can accelerate from a stop signal and hit a top speed of about 30 mph on that bike, and it climbs hills really good too! Can't do that with a hub motor... Oh and the Charger bike is very quiet.
My Speedmachine has a little gear whine from the planetary gearbox, something I'm working on...
Sorry I forgot, the E-bike. It only goes 16.5 MPH, even while trying to peddle! I like to go at least 20 + mph. I has fair acceleration but not like my Speedmachine, not even when the Speedmachine is at 35+ mph, its still pulls better then the E-bike at 5 MPH!!!
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