DIY Throttle Limiter
Permanently capping an electric scooters speed can be most easily achieved by limiting it's throttle output. This is important in countries where a device speed limit is regulated by law (eg. 25km/h in Singapore). Many scooters available for sale in the various markets exceed these limits.
Adding a variable resistor to the throttle output is the cheapest and easiest DIY solution. The resistor costs just a few cents and it requires only basic electrical knowledge. This works for any electrical scooter or bicycle.
Once installed you will need to tune the resistor until 'full throttling' gets you to the top speed you desire.
NOTE: common throttle wire coloring is Red(+5V), White or Green(Signal), Black(0V)
A 10K Ohm resistor or trimpot works well.
Related Article: Throttles