Originally Posted by Koyote

Take it with a grain of salt. Aerodynamic drag grows as the square of speed. In other words, if you are doing the 40k tt at a high speed, yeah, you might realize some real gains from shaving. At mere mortal speeds, you'll get smaller gains.

For context, this guy set a world record in the 4k Pursuit, and did it without shaving off that 'stache: