Q: Looking for a rear wheel 20 inch hub motor kit for BMX an need a 12t sprocket, also I have a 72v battery for ebike so wondering if I can get a bigger controller to use 72v battery also more amps mean more power is my understanding!

A: max 16t sprocket,we have 16 t sprocket.
12T doesn’t fit for 20 inch hub motor.
Our BMX rear 20 inch bike motor kit can work at 72v, but we should customize low speed if work at 72v battery..
what max speed would you like, 20 inch wheel?

Q: What’s the max speed, wanting 45mph or 50mph 

A: The fastest of our 20 inch bike motor kit works at 52v battery can reach 40mph
If work at 72v, 45mph or 50mph, should make low speed motor.

Q: What’s the OLD size for the drop out?

A: Standard is 135mm..
Not sure your bike, if possible, measure it very easy.

Q: Would u have a 20 inch hub motor kit for a 110mm rear drop out with flywheel for BMX?

A: yes,we have 20 inch 1500w BMX with single speed freewheel fit for 110mm rear fork
https://www.leafbike.com/products/diy-bike-conversion-kit/bmx-20-inch-48v-52v-1500w-rear-hub-motor-electric-bike-conversion-kit-1180.html

Q: What’s the kv eating of the motor so I can maybe switch to a bigger controller

A: The 20 inch BMX bike motor kit you bought that can work at 48v or 52v battery (min 40v ~ max 60v)

Can’t work over 63v, can’t work with 60v battery, can’t work with 72v battery..(Controller & LCD NOT support 60v, 72v battery)

Q: Could I change the controller an display out for 72v controller an display by chance??

A: We have one 72v controller in stock. can drive this motor..
but without LCD.

Also, if works at 72v, should re-customize a slower speed 20 inch bike motor. 

Q: My battery is a 72v 20ah battery pack!

A: 72v 20ah should use 72V controller.

This 20 inch hub motor kit works at 48v battery, can reach about 40mph (no load speed)

If this 20 inch hub motor kit works with 72v controller & 72v battery, it will reach 60mph.. it’s too fast..

We need to customize a lower speed so that reach about 40mph.