I shave because it keeps me a great deal cooler. In many parts of my life, extra clothing on hot days was a factor (welding/ fencing coach, etc), and I was having real troubles with heat exhaustion and dehydration. I was not sure about shaving at first, and wasn't an active cyclist at the time....but I did it anyway. The next day I went out in public in shorts, only to discover that the Redlands Bike Classic was in town and nobody noticed...which led to me digging my bike back out and starting to ride again.