I had a cromoly fork fail...
It was probably less about my being three hundred pounds and more about me using my new found ability to bunny hop 10 inches off the ground to bunny hop a two foot high tree trunk lying across a trail.
Now granted, in hindsight, the flaw in this basic math test seems obvious but when you are in your twenties, full of adrenaline and riding at 15mph down a wooded trail -- math skills are not always so proficient.
The things I did to that Rock Hopper under the guise of having fun borders on abusive.