Some info on here
http://www.rctech.net/forum/electric...hless-tc5.html
To get from 64 to 48dp it's (no teeth/2)*1.5
For 48 to 64dp it's (no teeth /1.5)*2
In my X-rays I run 100 spur 47 pinion with an internal ratio of 1.9 to get 4.0FDR and 35* EBT on small indoor tracks, would drop to 96 spur on a big track with more EBT, always checking temps