Originally Posted by dan_vector

For 17.5 blinky you probably want to start with an FDR of 4.0 which would be 48t pinion on the 96t 64dp spur you have fitted. You may have trouble getting that size of pinion on the V1 motor mount. Not certain about that but I know it didn't fit in the v2 mount.

If you went to 10.5 blinky you'd probably want to start around 5.5 FDR which would be a 38t pinion on the 96t spur.

If your running boost however the above would change. Boosted usually runs higher FDR's than blinky.

Use the serpent gear ratio chart to calculate FDR.