Also a lot of it depends on the kV of the motor.
For example, I was running my ebuggy at a track (it's a 1700kV) with a 16t pinion and the motor was hitting 180F but the ESC was not even breaking 90F. It's because it was winding out and sitting at max RPM too long.
I went up to a 22t pinion (experimented going up 2t at a time) and now it comes off on the same track at 110F for speedo and motor after a 10min main.