The Losi site should tell you what they recommend for temp on their stuff. Every Man. has a different "safe" temp. I know Novak says 165 for theirs and Castle says 200deg for theirs so there isn't really a genereal safe temp. but they all seem to be safe at 170 deg and below. I've seen Losi stuff run and they "live" at the 170deg mark. Like I said before when you run motors that are that "hot" you won't always be able to run them for long periods of time without a break... a 17.5 BL motor can run all day but my 5.5 stuff is meant for racing...<8-10 min... there are a ton of factors that can play into the run times with hotter motors.....