hi profess welder , well you can look at some of the losi nylon gears for a 1/10 scale trucks losi xxxt or the losi xxxnt
these nylon or delrin gears had various numbers of teeth on them 90, 88 ,86 , 84 81 some also would also work
on electric buggies , the slipper gears or trans has to be adjusted correctly for it to work and not destroy the internal gears in the transmission , its jumping that destroys these transmissions and spur gears the formula for the final drive gear ratio example spur gear 86t divide pinion 20 t =4.3 x the internal trans gear ratio = the final drive ratio probably with a 12 turn motor you want a 16 tooth pinion or 15 t adjusting spurs and pinions will either give you more bottom end torque off the line, but not top end speed also you must check heat on batts and 11 ,12 ,13 turn motors too i had a losi xxx bk that was insane fast with a13turn motor ok mugey