A couple more stats for the gear-heads out there.
For the GPR460 I will be using this.
- Rear sprocket = 20 tooth ( california excess BMX)
- Rear Wheel = 12.5" Diameter (Typical electric scooter rim)
- IGH 3-speed = 24tooth input/20 tooth output
- Engine sprocket = 12 tooth
- Crankshaft to Output-shaft ratio = 5 to 1
The setup I used with the old engine only differs in the IGH input sprocket, which is 21-tooth.
The gear calculator I use computes the 3-speed jack shaft and plots the potential speed of the combination based on RPM input values.
- 'max torque RPM' = shift point
- Clutch stall = lowest RPM of usable power
- Max HP RPM = the final reliable maximum RPM you achieve
- Max RPM with tail wind = perfect conditions RPM with a tail wind
Set all your values and then hit the start button. It is written in Flash so it will animate the power lines.