It has been an interest of mine for a e-bike for a while but I'm curious what is the listest e-bike out there? I prefer to pedal 90% of the time and only use the motor for ~5-10% when I'm on a hill. So I would prefer a small battery and a light motor seeing as I may only use the motor 10% of the time. I like the appeal and use of the motor for times when I'm tired after a long ride and it's dark coming home and I've cleared 3 hills on the way home to kick the motor on if some sketchy people are about as I'm coming over the hill and tired from my riding to kick the motor on and speed off.

Thanks in advance for the help.

I'm also about to make that plunge. I am aiming toward the Tonxin Mini Motor (also called the Nano Motor in England) with a 3.2 amp, 36v DeWalt LiPo battery.

The motor is 180 Watts, but has internal gearing and a freewheel that give it the torque of a 250 watt motor. Weight of the motor is 5 pounds and the battery is 2.5 pounds. Wiring and the controller should keep the total weight under 10 pounds.

I intend to use it on the front wheel of my recumbent where I can easily swap in in and out at will. As you can tell, this is not intended to be an electric motorcycle, just a boost up the small hills I encounter.

Some folks on a different forum reported problems with the company, but over the last several months that I have been watching it, the descriptions and product photos indicate that changes have been made in the motor.

Here is a link to the company (in China). If you take time to navigate, and you can learn a slightly skewed English, there is a lot of info.

https://www.tongxin.net.cn/tongxin1.jpg
https://www.tongxin.net.cn/tongxin2.jpg

I was going to say that the Nano was probably the lightest practical motor you could get, but Goat beat me to it. You won't do much better than that, some of these frame mounted motors come close when you look at how much the motor itself weighs, but they require you to *add* hardware, whereas the Nano is technically removing hardware since you're no longer counting your old hub.

BionX is the other light hub motor choice, although its not as light as the Nano it has more features, and mounts rear wheel instead of front. The 250w motor weighs about 7.5lbs as opposed to the 200w Nano's 5lbs.

Also, there are a bunch of frame mounted options out there that can weigh in pretty light. Some of them might say they have a 6lb motor, but they might also require you to pack on 2lbs of mounting equipment and an extra lb of drivetrain modification as well though. I'd look around though, something might be out there.

so rather than a like ebike it seems that what you are looking for is a lightweight kit to mount on the bike you have to make it go hmmmmmmmmmmmmm (the sound of a nice environmentally clean motor In your shopping I would also consider how/where the kits need to be mounted - it can make a big difference in the handling of the bicycle.

I know this thread is a bit old but I wanted to let you know that Freedom Ebikes have now released the world's lightest 250 watt (EU max power) e-bike kit. The entire kit (hub motor, battery, controller & throttle) adds only 3.2kg to the bike.
Add it to a 11.5kg Brompton and you have the world lightest folding electric bike.

Its based on the tonxgin (Nano) super mini motor mentioned earlier in this thread but uses the latest nano-technology lithium ion batteries and a number of other weight saving improvements.
I have been riding the proto-type almost every day for the last 18 months in a lot of hilly locations.
It eats up the hills and provides amazing acceleration to cruising speed (25kph).

Check it out at: www.freedomebikes.com

Google Gruber Assist.

That is excellent marketing. Sell someone the lightest, therefore smallest capacity and cheapest battery along with a small motor and charge a premium price because it's light. Li-ion or LiFePO4 are limited to a certain energy density. There's no magic, it's just a small battery. 91Wh so likely 24V and less than 4Ah.

So what is wrong if all one wants to use it for 10 miles only? And you can always add extra batteries to increase your range (and weight). It's marketing but 't's not deceptive marketing. And the price is well better than 250 or 350 watt systems.

The Freedom E-bikes kit is a 250 Watt system using a 36V motor. This is the max allowed in the EU & UK anyway.
Its not just because of the battery that it is the lightest. The motor only weighs 2kg and the controller 100gms. In most other ebikes the hub motor alone weighs more than the whole Freedom Ebike kit!

Its also not a premium price. At £470 pounds (US$790) for the basic kit (incl hub motor in wheel, battery, throttle & controller) its substantially cheaper than most of the competition. Even if you add another 2 battery packs (£200 for two extra packs) to bring the capacity to 273 W/hr, its still slightly cheaper than the competition.
But frankly, e-bikes are about functional transport, not long distance recreational riding and who really commutes more than 30km (2 battery packs) on an ebike?

Batteries are a big part of the cost of an ebike kit and the Freedom E-bike kit gives the consumer the choice of how much battery capacity they need and want to pay for.

In retrospect I was a little harsh before. I agree it is a good concept to add batteries as required rather than just having a 1 size fits all as is generally available. At the end of the day there's nothing wrong with making a reasonable profit if you offer a good product and good service. Best of luck to them, they have been creative and found a niche.

Thanks Lynchy. I appreciate your comments.

I've subsequently heard that its possible to spread titanium Brompton forks (see this month's AtoB magazine) so were looking to fit the Freedom Ebikes kit (3.2kg) to a Brompton SL2-X (9.8kg) to create what must surely be the lightest ebike (and folding ebike) - 13kg incl battery.

That is a good point. Another aspect of low capacity Lithium batteries is that they do not age well. Most manufacturers save weight by installing batteries that are undersized for the power drawn and therefore working too hard. This reduces the lifecycle of the battery. Going with lower voltages is OK as long as long as the motor is designed for high RPM's. I am an ebike manufacturer and I am not a big fan of hub motors, they are heavy and waistfull on low RPM's, harder to pedal, changing tires is a pain and they seem to be running into more of flats. I am installing 15Ah for my 350Watts bikes and 10Ah for my 250Watts European model. I know it is the policy of this forum to not post any links so I'll just leave you with the name: NEO VELOX

anybody know which factory makes this motor?