Does anyone know on the electric citibike how powerful is the front hub motor and what’s the battery?

The reason the bike will no longer assist after 18 mph is NYC has a 20 mph speed limit on electric assist bikes. Greater than 20 mph then the bike is considered a limited speed motorcycle which requires license, registration and insurance.

Citibike struck up a deal with NYC where the assist will cut off after 18 mph. Therefore if the bike is exceeding 20 mph it's due to human and/or gravity power alone.

According to their website, they have a 250 watt motor and are limited to a maximum speed of 18 mph. If you exceed that maximum speed the electric assist cuts out. You have to pedal in order to activate the electric assist

Contact citibike. The day this old man needs an electric assist bike, start digging my grave.