Cast Iron Drum temperaure too high??

[James G.]

The temperature was in the mid 80s when I took a test drive with new rear cast iron drums installed. Gone for maybe 20 minutes driving around the neighbor hood, stop and go,and then a mile or so down the open road trying a couple of hard quick stops. Returning home I checked the temp and one was at 175F and the other 190F.
Is this normal for this kind of use on a 80F day drive? What would be considered too hot, overheating?
All comments/experiences welcomed.
Thanks,
Jim G.