If your legs hurt when you start riding, and continue to hurt while you ride, you need more protein. Otherwise, probably not. Everyone's legs hurt a couple days after a hard ride, protein or not.

Protein requirements in endurance athletes are mostly dependent on hours per week of exercise, because it gets burned right along with the carbos. If you are riding 150 miles per week or so, I'd say it's a real good idea, but after exercise is the most important time, rather than in the morning.

Eating more protein than necessary for building or repairing muscle is just calories. However, it can have other benefits as it reduces appetite and thus can assist with weight loss.