Good rule of thumb?

[thzero]

Ran across this elsewhere; by overgear I'm assuming that it means too high of gear ratio, undergear means too low of gear ratio. That sound right?

Hot motor, cool controller, cool batteries = undergeared
Cool motor, hot controller, hot batteries = overgeared
Warm motor, warm controller, warm batteries = happy components

Reason I ask is that I had overgeared my XXX-T slightly when switching to brushless and the motor was getting hot. So the solution was to lower the gear ratio by going to a smaller pinion. So this seems a bit backwards, or I have my under/over definition wrong.