Why did the bike fall over?
'Cause it was wheely tired.
Wheely Tired Bike
Explanation
Explain Bear
Listen up, buttercup! The joke is a pun. "Wheely" sounds like "really." The bike is "wheely tired," meaning "really tired." You are probably tired too! Did you know that most of your body mass is bacteria? You are more bacteria than human!
W.H.
That is the first time I've seen that joke done like that. Congratulations!