Depends on what you're comparing. A real Ironman triathlete rides 113 miles in between swimming and running, and he/she does it fast. He/She would be a better athlete and cyclist than almost everyone on this forum. But if you're comparing it to the Tour de France and pro cyclists, they are obviously better cyclists. TdF is harder overall because it is thousands of miles. Your local TT or crit is not as hard as an Ironman.