15t pinion on 5s is crazy speed for sure, i run a 13t for 4 or 5s with a 1y, shoot 13t on 4s is fast enough!
Yeah i bought the 5s just to see what it would do, i prefer to run 4s and i will be, so u think a 13t will do the trick? 48/13 will give good temps on the motor?