I've been working on my xxx-t's gearing with a 13.5 novak ss pro motor. when i first ran it, the gearing was set at 23/86 and the temps were about 100-110F max. Just today I went to 23/78 and the temps only went up about 10 degrees even in fairly deep, loose sand-like dirt with the paddles on
After I test it out on my local track I'll probably be getting a bigger pinion.....maybe 25-28 tooth. I'm running nimh packs right now tho so the motor is probably a bit choked of power. Not sure how much would temps increase going to 2s lipos tho.
OP, keepin mind that our transmissions are different so final ratios will be different with the same pinion and spur.