Comments on: Electric bicycle

By: home made wind generators

home made wind generators — Sat, 27 Jun 2009 06:37:51 +0000

Engaging article,, will come back soon:D

By: Hitek146

Hitek146 — Sat, 20 Jun 2009 23:08:17 +0000

^Check with go-cart type racing supply…

By: Brian

Brian — Sat, 20 Jun 2009 17:55:22 +0000

Nice contributions from everyone, this forum is a blast!
Some people miss the whoe point of an electric bike though. These thinge are primarily fo ‘assist’ and not sport racing, so I wonder why the avarice towards more amd more power.
The essence I think is to weave in and out of trafic and get to your destination without breaking much sweat.
Any motor that runs faster than you can peddal is simply running too fast for your own safety let alone the law.
Im working on my own bike but I’m missing the drive sprocket on the motor. Any idea where I can find a 9T 10mm D-bore sprocket for bicycle chain?
I’d be glad to know.

By: eCo Wheelz

eCo Wheelz — Sun, 14 Dec 2008 19:05:27 +0000

Improved technology is creating longer-lasting batteries with extended life and range – all while prices continue to decrease. Electric bikes are becoming a more viable option than ever before and there’s been an explosion of DIY kits and new electric bike models.

Other posters have mentioned the laws that limit the speed of electric bikes to 20 mph – but this also allows you to avoid paying for insurance, registration and all the other fees associated with motor vehicles. It’s not very hard to upgrade a kit to do over 20 mph – and law enforcement is probably not going to know the difference if you’re going 20 or 30.

Either way, electric bikes are a great way of getting around – and saving money! Here’s a great place to find more information about electric bikes & bicycle models >

By: Morten

Morten — Sat, 18 Oct 2008 19:29:46 +0000

What about Hackaday made a guide about getting parts for a diy kit?
The reason for asking is that i dont know where to get motors and controllers from.

By: bancroft

bancroft — Tue, 14 Oct 2008 15:37:53 +0000

i’m curious, what effect would it have to connect the pedals and motor through a differential? wouldn’t it essentially add the two inputs? you could achieve higher speeds/more torque this way.

By: garygadet15

garygadet15 — Tue, 14 Oct 2008 14:27:16 +0000

Just a little info for those interested, the motor and the pedals have freewheels fitted so do not turn with the motor and you can pedal without turning the motor. The video of the wheel spinning was with no load so is faster than when under load. Also the 15.5mph UK limit is derived from the European law (or the other way around!) but generally either a 250watt or 200watt (350 watt for a tricycle) average rated motor is ok, top assisted speed is 20kph (15.5mph) the bike motor and batteries must not weigh more than 40kg and only 14 year old and above are allowed to ride them, but UK law allows for an average user speed , so if you weigh 9 stone and are 14 years old you will travel a bit faster than someone who weighs 25 stone, providing it is designed for an average user the law allows for a degree of variance. And has speed restrictions do not apply to cyclists in this country you can pedal has fast as you are able….The cyclone was my choice (over the Wisper) as it drives through the gears, in a lower gear it allows me more torque and climbs quite steep hills at a very reasonable 15mph but in top gear it will travel at 22mph depending on wind etc. this allows me to add to the motor assistance with pedalling so I can keep up with normal traffic flow (very much like the newer Panasonic bikes out now but a lot cheaper). The gearing dictates the speed more or less. With hub motors it’s the controller but again the rider’s weight and conditions vary the speed somewhat, though I would add that Hubs seemed to assist you to 15mph and added drag when you want to pedal faster, the cyclone just freewheels when I pedal faster than its maximum speed. As for the motor position this is a compromise, low down and central to the bike, makes for a better balanced bike but also is in a position to be splashed, though I have not managed to knock it yet, as it seems to be high enough to be out of harm’s way. A hub motor is a heavy piece of kit and fitted to a front wheel can feed back through the steering (not very nice), in the rear wheel it can make the bike back heavy and not very nice in the wet. Ok not that little a reply – but anyone interested in an alternative commute to work I would highly recommend you get an electric bike, but with a very bright yellow coat and a load of flashing lights and a book on cyclecraft, and just keep on believing those motorists really just did not see you!!

By: Mastro Gippo

Mastro Gippo — Tue, 14 Oct 2008 06:34:54 +0000

Hi, there are some sites around dedicated to ebikes, the more important is:
http://endless-sphere.com/forums/index.php
There are a lot of material there available for anyone to build their own bike. There’s also this guy, Justin, who made a coast to coast trip of CANADA on 10$ electric bill: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=5652&st=0&sk=t&sd=a
Join us on the forums!

By: brian

brian — Tue, 14 Oct 2008 04:06:15 +0000

nubie: ah, I see my mistake. I hadn’t taken into consideration the fact that the controller is supposed to cut out at 15 mph, and so if the wheel is spinning faster then it obviously didn’t (whether the wheel is pushing a person or not). OTOH, the speed sensor on the bike in the video could be on the front heel (which is not spinning).

orv: I’m not sure what you consider suitable for riding in traffic, but most cyclists consider 12-20 mph plenty fast enough.

By: Orv

Orv — Mon, 13 Oct 2008 15:56:32 +0000

The laws revolving around electric bicycles are actually quite a hindrance. It appears that, in my state anyway, an electric two-wheeled vehicle that can go faster than 20 mph is simply not street legal. It doesn’t meet the requirements for an electric bicycle, and it doesn’t fit the rules for a moped, either. This means that the only electric vehicles you can find are ones that are too slow to be suitable for riding in traffic.

By: jerohm

jerohm — Mon, 13 Oct 2008 15:38:26 +0000

seems like the motor wheel can not run free on this system. Which means the pedals will have to turn when the engine is running. (no free run, you’ll have to move your legs all the time)
Plus, in the other way, it seems difficult to pedal without the motor running as you’d need to go against the motor resistance. This means it would be exhausting to go back home once the battery has run out out of power…

By: ken

ken — Mon, 13 Oct 2008 14:06:15 +0000

nubie: All electric motors have a top speed for a given supply voltage. For brushless hub motors that speed is theoretically their Kv rating multiplied by battery voltage. Above this speed, the motor’s back EMF exceeds the driving voltage, preventing the motor from drawing power.

Increasing the top speed reduces low end torque. Chain drives with multiple gears are generally thought to provide better torque with good high speed performance, at the expense of complexity and more stages for mechanical losses to add up.

Cheap motors tend to be bigger, heavier, hotter, less efficient, less reliable, and lower power. You can always find a motor that costs less. The notable thing about these motors are the availability of high power (1500 watts = 2 horsepower!) in complete packages at low prices. Lead acid batteries work OK (cyclone even sells them) though they are heavy, lose capacity quicker, and contain lead which *must* be recycled.

Lastly, I followed the links before “knocking” the product. I stand by what I wrote. If you want to build an ebike with the motor inches off the ground I wont stop you, but please try to add a better chainguard.

By: Bates Electric

Bates Electric — Mon, 13 Oct 2008 03:49:22 +0000

Terrific Service!

By: nubie

nubie — Mon, 13 Oct 2008 03:01:29 +0000

Haku, racing and transportation are two different things :).

Why does the hub motor have a fixed top RPM? That must be a limitation of the controllor/windings/permenant magnets/batteries, as theoretically a brushless doesn’t need to have an RPM limit.

Cool, I wonder if you could use a cheaper motor and a lead-acid battery instead, but the controller is still an expensive item I suppose.

By: Haku

Haku — Sun, 12 Oct 2008 23:57:21 +0000

I went to the 2nd day of a 2 day electric bike event in Wales earlier this year: http://www.tourdepresteigne.co.uk (I’m no.21 in the photo gallery, only one main pic of me at the bottom of the last page)
the big event of that day was the 1 hour rally through the small town – which was very hairy at times because we were going through a churchyard whilst people were still using the church!
I decided to ride with the 15mph speed restriction on because last year the road-legal winner was also on a UM36, but afterwards I wished I’d derestricted it (simply by unplugging a wire sticking out the controller) because most of the time I was going faster than 15mph to try and keep up with everyone else and that meant the motor wasn’t giving any extra boost, in fact it was having the opposite effect because I was pedalling against the motor (effectively in dynamo mode).

Some of the riders on non-road legal bikes had special gearing setups and were easily achieving 30mph, lapping me several times by the end of the race.

@brian, my derestricted UM36 tops out at 20mph on the flat with the throttle only because the motor won’t spin any faster, the bike shown in the above video has the motor powering the wheel through the gearing system which means it can go faster than a fixed geared motor (ie a hub motor like the one on my bike)