is this motor uk road legal ? on a ebike

Tony1951

Finding my (electric) wheels
Jul 29, 2025
11
5
the ebike has stickers saying it complies to uk law ie 250 w and 25 km/h but the motor is engraved 48v 20" so assume it is 48 volts and 20 amps which is 960 watts. so is this legal in the uk for use on roads ? thanks
The 20" part means the wheel is 20 inch, nothing to do with amps.

The other photo contains the necessary information confirming that the motor complies with UK law for use as a bicycle on the roads - EN15914 standard from 2017, and specifies the maximum continuous power output of the motor - 0.25kw, or 250 watts. It also shows the maximum assisted speed - all required to be displayed to comply with UK law as a legal e-bike - treated exactly like an ordinary bicycle.

If it is not fitted with a throttle, so that you have to pedal to get power, it is legal.

Edited for clarity.
 
Last edited:

wizdumb

Just Joined
Aug 1, 2025
3
1
The 20" part means the wheel is 20 inch, nothing to do with amps.

The other photo contains the necessary information confirming that the motor complies with UK law for use on the roads - EN15914 standard from 2017, and specifies the maximum continuous power output of the motor - 0.25kw, or 250 watts. It also shows the maximum assisted speed - all required to be displayed to comply with UK law.

If the bike controller is not fitted with a full speed throttle so that you must pedal to get power, it is legal.
ok thanks
 

Peter.Bridge

Esteemed Pedelecer
Apr 19, 2023
1,741
773
And if you did connect it to a 48V 20 amp controller it would still be UK legal as long as it restricted the maximum assisted speed is set to 25 km/h or below. (because the rated maximum continuous power of the motor is 250W)
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
8,986
4,019
Telford
ok thanks
Just to let you know that there is no law relating to actual maximum output power allowed. The law is that the MOTOR must be RATED at no more than 250w. The next thing is the difference between input and output power. Let's say you had a 20A controller. The maximum input power that the controller would allow would be about 1000w. Don't forget that the 48v battery is 54v when fully-charged. The output power could be anything between zero and about 700w, depending on your speed. The speed affects the efficiency of the motor, which is zero when it's stationary and about 70% at around 75% of its max speed. It's virtually impossible to test that because it's a moving target.

In simple terms, if your bike or motor is labelled by the manufacturer as 250w or less, it's legal. If it has 500w written on it, it's illegal.