Q: Hello! I have been viewing your various 20″ 48v/52v front hub motor diy bike conversion kits and I have a couple of questions.

1) Is there a way to install a disc brake rotor somehow next to the hub motor and still function properly? If so, can you tell me maximum rotor size allowed for these kits?

2) What type of battery would you recommend for a 48v/52v front hub motor kit like this?

Thank you very much for your time and assistance regarding this matter. 

A: 1.) Can install a disk on this 20 inch 1000w or 1500w front hub motor… but the front dropout should be 105mm or 110mm..
    Standard front dropout is about 100mm..

So if the dropout can’t be larger, can’t use disk on front motor.

2.) We recommend 52v 20ah lithium battery.
https://www.leafbike.com/products/lithium-battery/52v-20ah-1500w-electric-bike-battery-triangle-battery-1225.html

Q: Thank you very much for your quick response. Do you know what the maximum disc brake rotor size I would be allowed to install next to motor? Thank you again.

A: We installed max 160mm

Below picture. 
The dia. of two holes for disk is 44m…
If your 180mm 203mm,  aslo 44mm… You can install 180mm, 203mm disk

Q:
I forgot to ask you one last thing before making a final decision on a front hub motor kit. I know you said you are not able to ship the recommended 52v 20ah battery to Japan, but can you recommend a charger to go with this type of battery? Thank you again for all of your help and assistance. 

I just noticed the charger that comes with the 52v 20ah li battery, so I can look for battery/charger here in Japan. But, do you have in stock just the frame bag for holding this type of battery?