Here is a video of what a four hour, 56-mile bike is like during a 1/2 Iron-Length Triathlon (a 1.2 Mile Swim, 56-Mile Bike, and 13.1-Mile Run). This video was taken during the Napa Valley Vintage Triathlon. My Race Recap can be here.
RACE DIRECTOR’S WARNING: (1) Participation in this event may indicate an impairment of your ability to perceive the normal limits of human exertion. (2) Athletes who start a routine of swimming, biking, and running often find it difficult to quit.