While monitoring the A320 aircraft systems during cruise I noticed that brake temperatures are relatively high compared to the OAT. I have seen brake temperature indications range between 20°C and 120°C during the cruise, when the OAT is generally around -55°C.
I would have always assumed that the brake temperatures would naturally cool down, but even hours into a flight brake temperatures are consistently high compared to OAT. Is there any reason for this? I haven't been able to find any answer on the FCOM or FCTM.