I live on a small mountain with lots of 100 metre-long 30 degree slopes, up and down.

 

I do not require long range or high speed.

 

I require 30 degree-slope climbing assistance, the ability to freewheel, and the ability to pedal with zero-drag and cogging, or to easily disconnect the motor from the wheel.

 

I can contribute 500W of leg power.

 

What not too heavy electric bike would you recommend: hub, geared hub, roller-drive, mid-drive, front or rear, 250, 500, 750, or 1000W, 36V or 48V?

With 500w from yourself, any of the higher torque crank-drive bikes should be OK.

 

If you want a DIY bike, two systems come to mind: The 48v Xiongda rear hub-motor, which is vaguely legal in Europe. It's very light, silent and totally free-running Alternatively, a 750w BBS02 Bafang crank-drive. A 48v 500w BPM at 25A would do it too, but that involves a bit more size and weight.

The 750 watt BBS02 would be oefect for your needs mounted on an MTB with a 34 tooth granny gear and 44 tooth chainring

If a 750W geared hub motor is used up a steep slope, is there any real difference whether it is on the front or rear wheel?

Edited August 23, 201510 yr by mifletz

Any hub-motor over 250w should go on the back wheel unless you have strong steel forks. Geared ones only go up to 500w, but the rating doesn't mean much. The Q128H is rated at 800w, but it's smaller than a 500w BPM and probably gives less power.

Although a roller's efficiency is less, its stealth value looks tremendous.

 

The question is the e-add in its 600W version is enough?

 

Try it and tll us the answer.

Although a roller's efficiency is less, its stealth value looks tremendous.

 

The question is the e-add in its 600W version is enough?

 

probably not.

cant see it being much good in the wet either.

if the roller slips on a wet tyre and or a steep gradient, the add-e can transform itself into a 600W dremmel.

cant see it being much good in the wet either.

 

It is claimed that:

 

http://www.bikerumor.com/2015/05/14/the-add-e-electric-motor-kit-is-generating-watts-of-interest-on-indiegogo/

"The coating on the motor’s friction roller has been tested and will reliably help drive your tire in rainy, wet conditions."

But a year since it came out and I have yet to read a proper review of the add-e, which probably means that at 1000 pounds it is hyped. If it does turn out to be any good, expect Chinese copies at 500 pounds within the year.

Edited September 1, 201510 yr by mifletz

Somebody has to put their money down and try it. Then we'll all know. We can't all wait for somebody else otherwise nobody would try anything new and their would be no valid opinions about anything.

Could that somebody be you?

Being that each add-e dremel is made individually by a lone Austrian watchmaker, there is a 4 month wait for delivery, so I am reluctant to put down 1100 pounds up front. They claim that the 600W version cannot be used with anything accept their original bottle battery, and acknowledge that there has not yet been an independent critical review of it yet. I believe that it could fulfil my only requirements of: stealth, lightness, the ability to totally disconnect from the rear wheel, and to provide 35% assist in the dry up several 100 yard long 30 degree slopes at 5mph. They say they are making a video purportedly showing its ability to perform the latter.

Edited September 1, 201510 yr by mifletz

wait for this then http://www.b-labs.org/e-ram/

wait for this then http://www.b-labs.org/e-ram/

Well done, nice find, I like that alot if it happens.

You see a lot of these sorts of ideas floated but how many of them actually do what they say on the tin? Lots of people would like a genuinely lightweight bike which still gave good assist - or even just a little bit of assist for hills and still be reliable - but will it happen in my lifetime?

the people who go on kickstarters or indiegogo tend to exagerate the features of their designs when comparing to existing products and that puts me right off. Plus, their backers are offered zero protection against non performance.

Bafang have an option for a "push-button e-brake".

http://em3ev.com/store/index.php?route=product/product&product_id=198

 

What exactly does it do?

 

http://em3ev.com/store/image/cache/data/brake%20switch-250x250.png

 

For mainly slow hill ascents, is it necessary?

Edited September 4, 201510 yr by mifletz

...

For slow hill ascents, is it necssary?

 

quite the opposite. Push it and the power to the motor is cut.

It's for bikes that can't have brake sensors.

quite the opposite. Push it and the power to the motor is cut.

It's for bikes that can't have brake sensors.

Oh dear, sounds like braking is an elaborate maneuvre on such a system. Talk about dangerous.

I can't see how such a tiny cylinder is supposed to generate torque to go over a speed hump let alone a 30 degree hill which will make 8 inch diameter motors overheat in a matter of seconds.

the lack of system ventilation forces the designer to leave the motor core exposed to mud and water ingress.

 

http://brimages.bikeboardmedia.netdna-cdn.com/wp-content/uploads/2015/05/add-e-motor-close.jpg

quite the opposite. Push it and the power to the motor is cut.

It's for bikes that can't have brake sensors.

Oh dear, sounds like braking is an elaborate maneuvre on such a system. Talk about dangerous.

That's not what it's for at all. is just a switch to switch off your motor when you want, instantly, like when you want to change gear without crunching, or negotiate a pedestrian infested zone.