Infrared (FLIR) image of a bicycle after a ride. It is interesting to see the parts of the bike the warm up the most and the parts of the bike that are cold. For instance, I would think the bottom of the work would have been more active and therefore generated more heat, but it seems ice cold. The top tube and part of the bottom tube are almost completely cold. The head tube, wheels, and groupset in general are hot, which makes sense if you think about it.