Alright, I was bored the other day and decided to make the longboard I just purchased into an electric board. (Too lazy to pump all the time) A couple hours later here's what I have. The designs are pretty crude but they work.
-Yoacher 41 inch drop deck board (The one i have)
-Hobbyking 5055 400kv motor
80+ amp speed controller
-55 teeth 110XL synchronous belt
1.5mm Pitch 10 Teeth 6mm Bore Motor Part Timing Belt Pulley Sprocket
2ch R/C car radio and reciever
Your choice of battery (3s runs perfect I'd say around 10-15 mph 6s for dangerous speeds)
That's pretty much it I printed the parts at 0.2mm layers at 100% infill on my prusia i3. Epoxy the wheel pulley onto the wheel and its good. Make sure its centered to avoid vibrations.
Bracket is friction fit so hammer it good in there.
Works well and cheap.
Oh yeah, you're going to need some extra spacers for the wheel if you cant hammer the bracket in enough. 1-2mm distance from the wheel gear is good. I have 3 spacers or washers on my wheel.
Battery tray is a friction fit for the battery as well for a Multistar 5200mah pack 23x50x145mm
This is what worked for me, do it at your own risk.
Got a new rc car esc (120A FVT)which has better acceleration and braking curve. (So much better!)
drilled and added grub screw to the motor mount to axle to prevent it sliding to the wheel gear under hard vibrations.
printed parts in new color and just got red wheels. Runs like a dream!
Phew, found an awesome upload by droftarts (Parametric pulley - lots of tooth profiles)
(awesome openscad file)
Used his scad file to create a wheel gear that fits the belt PERFECTLY. 37 teeth.
less area to epoxy onto the wheel but its enough. (Wait atleast 24 hours for it to cure)