Legal motor RPM

[Pedalo]

I just noticed on the Electric Wheel company website that they ship 190rpm motors as standard for fitting to 700c wheels, whereas Cytronex sell 175rpm as standard and state that 190rpm motor is not legal.

What's going on here? Are EWC being a little 'naughty'? or is it that the controller is somehow tuned up in a different way on EWC vs Cytronex so both actually top out at about 15mph?

 

[Mussels]

The maths will make my head hurt so I'm going to accept Cytronex's answer. However the motor could easily be put in a smaller wheel making it run at legal speeds so there's nothing wrong with selling it. The thickness of your tyre can make a legal bike illegal so motor rpm is not a simple thing to specify in law.

 

[dan]

I just noticed on the Electric Wheel company website that they ship 190rpm motors as standard for fitting to 700c wheels, whereas Cytronex sell 175rpm as standard and state that 190rpm motor is not legal.

What's going on here? Are EWC being a little 'naughty'? or is it that the controller is somehow tuned up in a different way on EWC vs Cytronex so both actually top out at about 15mph?

If the overall diameter off the wheel and tyre is 700 cm then 190 rpm with give 25 kph or 15.53 mph, which would apeear to be over the limit of 15 mph and that is the UK road traffic act regulation speed, which would in my opinion be nit picking.....The new EU electric bike standard coverd it by giving a +10% leway that off course is not UK law yet.

 

[HarryB]

Cytronex estimate is a little low as I calculate 185 to be the ideal motor. Also they use nimh batteries that kick out less voltage than li ions. So overall my Cytronex pulled to about 14.5 mph which is little on the low side and I wouldn't expect you would be breaking the law with the 190 version (well I would go for the 190 version if I ever went back to a tongxin)

 

[piotrmacheta]

High rpm motors are Ok to use, you just run then at a lower voltage. The rules are based on power and speed.
I used to run my 20" wheeled eZee hub on 48V to get up to ~15mph but then bought a 300rpm hub and ran it at 37V to get the same speed.