The Great "Gearing vs Hub Motor" Debate

Miles said:
Ok, that makes sense.

Is the U.S. 750 Watt limit, for the peak output, rather than the motor's nominal continuous rating, then?
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So far the laws seem to allow the continuous rating value, so like in my case the 750 Watt motor can actually put out about 1000 Watts at peak power and still fall within the definition.

1000 Watts is 1.34 horsepower... which can get you up above 35 mph.

:arrow: I've just done some quick calculations on the "sit verses stand in the wind" idea and when you stand up and increase your frontal area you AUTOMATICALLY lose at least 200 extra watts in terms of increased wind resistance at 30 mph. So it basically means that pedaling while near full speed is pointless. But on a hill where the speed drops then the extra power is useful... all of it gets passed along towards the actual task rather than pushing wind.
 
Living in London, I'm not that interested in going more than 20mph (it's too risky). What I want to do is cruise around at 16mph, on the flat, using pedal power alone, and then be able to maintain that speed on most slopes, by adding motor power. So, increasing the average speed rather than the maximum.

This has the additional benefit of maintaining airflow cooling (for me) on hills :)
 
Living in London, I'm not that interested in going more than 20mph (it's too risky). What I want to do is cruise around at 16mph, on the flat, using pedal power alone, and then be able to maintain that speed on most slopes, by adding motor power.
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A worthy goal. Safe is an aging bike racer undergoing a midlife crisis. Making generous allowances for that, we cut him slack, praise his initiative, and overlook most of his spreadsheet errors. :D
 
The electric bike will never become popular until it starts to appear "cool". By adding the "sexy" road racer angle to the electric bike it will attract people to it as well as the law. So it's more important to make such a bike pass the letter of the law than someone who "hides" behind the "dork factor". The hub motor mountainbike definitely keeps the police away, but it also keeps everyone else away.

:arrow: So it's a tradeoff...
 
So it's more important to make such a bike pass the letter of the law than someone who "hides" behind the "dork factor".
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You're just jealous of my clever methods :)
 
It's very devious to be riding around on a bike that pumps out 4-5 horsepower and "look" to the world like you are doing nothing to worry about. I'm riding around with a leather jacket, a full faced helmet and look like I'm on a motorcycle... the ONLY reason I get away with it is that my bike does satisfy the laws for Missouri very easily. (since we are allowed up to 3 horsepower here) So the cops here just don't have any law to enforce.

:arrow: What was the legal limit for power in your state again?
 
If I'm wearing a jacket, full face helmet and look like I'm on a motorcycle, I'll be riding a motorcycle. I'll refrain from commenting about riding an e-bike with full motorcycle gear... :lol:
 
Lowell said:
If I'm wearing a jacket, full face helmet and look like I'm on a motorcycle, I'll be riding a motorcycle.
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What I'm doing is an idea that sort of merges the motorcycle and the bicycle into something that is a little bit of both. Most people have tried to simply "enhance" the bicycle with a motor. Others have reinvented the motorcycle as an electric motorcycle. I'm trying to find that "sweet spot" in between the two.

If I pull this off right there might be a whole new industry that is created as a result. (imagine seeing one at Walmart)

One man really can change the world... (in small ways)

I know is "sounds" insane to think you can have an effect, but you would be surprised sometimes. With the internet all you need to do is spread a picture around and eventually it takes off.

But I have to ACTUALLY build something first... my existing example was my "trial run" and I've been doing my homework. I've finally mastered all the elements of the powerband / gearing / etc in the spreadsheets (which was no easy task) and so now it will be about building the next generation bike.

It will be interesting... 8)

It definitely helps to make things look "cool". Why do people instinctively find this shape attractive?

Because it "feels right".

That's what is my goal on this project...


dbimage1445_300.jpg


When you think about it it's the perfect marriage... aerodynamics and the electric bike. Throw in "fun" and you have a great ride...
 
What was the legal limit for power in your state again?
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1000 watts, I think. Which is 250 more than my officially 750 watt motor. I've room to spare! And since I'm usually riding at less than half throttle, my average wattage for any ride is far, far below that 1000 watt limit. :D
 
safe said:
:arrow: Because our American National Electric Bike Definition defines an electric bike as:

1. 750 Watts.
2. Must have pedals.
3. Cannot exceed 30 mph on motor power alone.
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Somehow I thought it was 20mph for an electric assist bike, and 30mph "motorised bicycle" aka moped.
 
Mathurin said:
safe said:
:arrow: Because our American National Electric Bike Definition defines an electric bike as:

1. 750 Watts.
2. Must have pedals.
3. Cannot exceed 30 mph on motor power alone.
Click to expand...


Somehow I thought it was 20mph for an electric assist bike, and 30mph "motorised bicycle" aka moped.
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It is. Safe was mistaken/made a typo.
 
Mathurin said:
Somehow I thought it was 20mph for an electric assist bike, and 30mph "motorised bicycle" aka moped.
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:arrow: It's 20 mph.

In Missouri the law allows 30 mph, so I have a bad habit of substituting the local law. I will comply with the national law. (or at least make it possible somehow in the default configuration)
 
can some one explain the difference btw the two and why they're not rated the same? how do you compare them? iv'e seen the hub motor simulator but not a regular dc motor simulator.
 
kisshu said:
can some one explain the difference btw the two and why they're not rated the same? how do you compare them? iv'e seen the hub motor simulator but not a regular dc motor simulator.
Click to expand...

All motors operate within certain mathematical rules and principles. It does not matter how you package a motor, either in the hub or standing alone, the rules for how they behave are the same. That's not to say all motors are the same however... by skillfully combining material elements together in the construction of a motor and doing things like lowering the motors resistance you can get better overall performance. There's also controllers and brushed or brushless or AC options, so it all gets rather complex.

You should download my "study guides" in the "Motor University (Lab 101)" and play around with the spreadsheets. After some fiddling it will start to make some sense. (I hope)

The main thing to remember is that electricity does not respect brand loyalty when it produces energy out of a motor... we all live with the same laws of physics...
 
i did a search for hub motor watt ratings and didn't find anything... any time i do a search it just comes up with all the posts that contain those words - thats not helpful at all. i'm looking for specific info:

1.hub motor watt ratings:
2. dan drapers motor: what parts are used and how he built it and the performance chart; how he mounted it.

the search doesn't help and i've looked through days of entries on motor 101 and others. :cry:

i've also sent e-mail to draper at invalid addresses and his site: ev-motors.com looks like it was hijaked or something :cry:

i don't have spread sheets- i only have the library computer and i can only access online simulators.
 
Hello, my name is Colby and I am new to this forum. I have built two geared bikes and I must say they are the best for my area (sf) pictures to come soon :)
 
Welcome to the ES forums colby. You should think about making threads about your builds as the look very interesting and there will no doubt be questions about them.

Is that the 600W unite geared motor on the dark bike? Do you have any performance numbers for your creations? Please tell us more you teaser!
 
thanks for looking. sorry it took a thousand years to get back to you. i didn't realize anyone had replied :oops: yes it is the 600watt geared unite. i am using 48v(lead) with a 50a controller(2400watts) :D its geared way down to the tune of 22mph, but can climb a wall if needed...not to mention only takes 3-4 seconds to get to that speed. this is the first one i built.

the other i am not happy with yet :( more to come on the 2nd bike as i am rebuilding it :twisted: i will tell you that i will be using bosch fat packs and two 450w geared unites :) perhaps i will start a tread for the new one :wink:
 
Colby
definatly start a thread on either of your builds or even better both of them,as im sure your information would be graetly appreciated
good job
 
colby said:
http://www.facebook.com/photo.php?pid=244019&l=ba61b49f6a&id=1364351739

http://www.facebook.com/photo.php?pid=251228&l=f7cf8026e7&id=1364351739

http://www.facebook.com/photo.php?pid=244022&l=b6c9ff767e&id=1364351739

http://www.facebook.com/photo.php?pid=251227&l=a86ae7df37&id=1364351739

http://www.facebook.com/photo.php?pid=244020&l=88de3f2281&id=1364351739
Click to expand...

Hello Colby! I have just noticed that you also live in the same city as I do. I have just checked out your ebike. You've got a nice built. Can you tell me if your 8mm sprocket is a freewheel or non-freewheel on the wheel? Or do you have a freewheel sprocket on the motor?
 
hey lyen.

thanks for taking a look!

its a #420 sprocket and chain with no freewheel and unfortunately no freewheel on the wheel. the sprocket on the wheel is bolted on :|
 
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