If they cooperate fully, Rider A has the strongest chance of winning the race. If Rider A defects, he has a lesser chance of winning the race. If Rider A cooper

If they cooperate fully, Rider A has the strongest chance of winning the race. If Rider A defects, he has a lesser chance of winning the race. If Rider A cooperates and Rider B defects, Rider A has the worst possible chance to win the race. I’m not sure how you see this as being a better situation for Rider A. Note that in my example I am, for the sake of simplicity, assuming a single race and am not talking about a stage race where one rider might be stronger but would happily agree to take second because the stage win is of lesser value than the overall time. When I refer to a stronger rider, I mean one who has a solid chance of holding off the pack solo, whereas the weaker rider would almost certainly be unable to be. When the two reach the finish line, I assume they would be reasonably well-matched for a sprint, just for the sake of providing a simple example. In reality, it’s rarely so clear. But if someone knows that cooperating and getting second place is a better result for them in practice than fighting tooth and nail for first and potentially throwing it all away, they’ll make this kind of offer. Likewise if the other cyclist strongly values first place but thinks it’s too risky to cooperate with someone who might be try to snatch victory away at the finish line with a sprint, they’ll be relieved to hear the other person give this offer. Making this offer and reneging is considered poor sportsmanship, and it rarely happens because (presumably) racers expect that doing so will prevent them from being trusted to cooperate in the future.