Which pinion to choose?

[ZacM80]

I had bought an Arrma Granite boost, and upgraded it to my 4370kv motor. It’s been a couple of weeks now and I’m seeming to have blown my first spur gear. The car’s always been a little unsteady at low end speed with the standard 91t spur, anyone have any suggestions for a better spur to pinion ratio, for a little more top end. (Haven’t bought the boost kit yet).

 

[parcou]

Welcome!