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Yes, the voltage at the 3 wire phase wires appear to be 18V but the average current flowing through the motor coil relates to the mark space ratio between the fine pulses. The impedance of the coil varies with the fine pulse frequencies. You can express the relationship between voltage and...

I think both NRG and d8veh are correct, two sides of the same coin. The current flowing through the motor induces back EMF, as per V = -L delta I / delta T, L being the impedance of the coil. It's worth to remember that these things are not static. the back EMF is picked up at the phase wires...

One thing that d8veh said makes sense to me though. If the throttle setting is converted into current control (between 0-15A for example), that would mimic better a torque sensor. Is there a controller that works this way or one that one can program oneself?

Manufacturers measure torque and speed (in RPM) of their motors at different voltage and current with a dynamometer. The power in W at the shaft is roughly = torque in Nm * 2 * pi * rpm/60. EN15194 measures power after friction loss (of the whole bike), a little lower than at motor shaft. All...

Meita, as you are 5ft4, you may be better off with a step through bike as these tend to have lower saddle height. ST are also better for keeping your balance at traffic lights.

More of a reason for derailleurs.

Half of Kalkhoff range have derailleurs, all Haibikes have derailleurs. If the chain comes off or if you have a puncture, hub gears are right pain.

picture of the cup You can buy with the skewer but you don't need the skewer. Your local bikeshop will undo the axle nut and install the cup for you. 15 minute job.

I think an 11-36T (eg CS-HGS62-10) derailleur is best for crank drives. Only the Rolhoff can beat that.

I had a quick look at the EZ hitch, it looks quite straightforward. You only need to buy a new cup for the new bike, no need for skewer.

I think that retailers are scared of being held responsible for any recommendation they may make when children are involved. If you ask for a bike that can pull 30kgs trailer uphill, lots of bikes can do that. I'd say the Tonaro Compy should do it. Then get your local bikeshop to hitch the...

but you did go a lot faster than 16mph on the Sirocco CD...

The NuVinci can change gear under load, Shimano hub gears also can but may incur a second or more delay and derailleurs may bang the chain. d8veh has extensive experience on this and came up with a solution for chain banging, using his thumb throttle. That d8veh solved the problem comes as no...

point taken d8veh but as 103Alex1 said in this thread: http://www.pedelecs.co.uk/forum/electric-bicycles/14309-help-needed-5.html#post176405 If you get caught speeding, you could lose your driving licence.

I don't expect to see Hatti be happy about customers desrestricting her bikes!

Fibreglass is a solution but what happens if the bike falls over? The soft pouch cells are made of very thin sheets, a dent in a corner of the pack or a puncture in the casing can be risky.

10mph wrote a very interesting piece a couple of years ago to show how manufacturers can get EN15194 certification despite having apparently powerful motors: http://www.pedelecs.co.uk/forum/electric-bicycles/8743-en19154-power-test-gives-incorrect-high-values.html Jemery also posted something...

Derailleurs don't lose much power through friction, hub gears and the Nuvinci do. In the case of the Nuvinci, progress in reducing friction loss depends on oil chemistry. At the contact point, you have two oil surfaces coming into near contact, one surface is the ball and the other the input...

My neighbour bought one of those. He installed it on his garage wall, hang his beautiful Trek on it, went get the hose pipe, came back. The head already came off. His Trek weighs a mere 11kgs. The thing does not have enough rubber cushion, the clamp nut kept unspun. No, it's not good.

alex, please correct me if I am wrong but don't you need a metal case and inside cushion for your battery pack?