mine ran good in my stock chassis conv., used 15/40 and close ratio 2spd, with mech. brakes and a center diff, i would say that 13 or 14 tooth would be fine, just avoid long grass and heavy tires

i only blew it up after i put it in a g3r(heavier chassis) and had the wrong gearing


http://www.youtube.com/watch?v=M0q7l8_5x2Q