18/51 too high

do u guys think 18/51 or mabey 20/51 is too high this is my setup 9918/8xl ,aluminum racebomb chassis widetrac suspension, racer x shocks,stock diff gearing,jumbomaxx claw dawgs , fan on controller and motor and 18cells. i run 16/51 now just kinda wondering how far i could push it. thx todd

[MetalMan]

Your gearing right now is probably good enough. You could try the 18t pinion, but I think it might be a little hard on the motor/controller.

[Serum]

try a 14 or 15/51 and 20 cells!