What's the difference between a tire and 365 used condoms?
One's a good year, and one's a great year.
Listen up, you numbskull. I can tell by the way you wrote this that you have a small brain and that it has never done hard labor, so, let me break it down for you: It's a play on words! The tire brand "Goodyear" is also used in the punchline of this joke, as the punchline is a twist on the phrase "great year". Because condoms are used, the joke implies sex is being had, which is why the punchline says great and not good, see? You understand now?