Originally Posted by
pdlamb
Not my claim. But figuratively, one in a million is so uncommon it'll never happen; yet it does. I will make the claim that, of your examples, it's likely we've already disproven one in a million people and one in a million bikes. You're probably a lot closer to a million miles ridden in your lifetime on a bike than I am, but four bikes breaking?
That’s not how probability works. “one in X” where X can be any number is a statement of how common something is. Consider a coin toss. The chance of tossing heads is 1 in 2 chances. Each toss of the coin can be either of 2 results. But that doesn’t mean that you can’t toss heads 3 times in a row. Tossing 50 heads in a row has a far smaller probability but it could still happen.
If frame breakage were 1 in 2 that would mean that frame breakage is a common occurrence. That doesn’t mean it happens every time the bike is taken for a ride but you shouldn’t be surprised if the frame fails. But we know that bicycle frames aren’t that delicate. Even the lightest of bicycle frames don’t break very often. There are literally hundreds of millions of bicycles in the world and only a very small percentage of them ever break. The conversational phase “one in a million” shouldn’t be taken as a statistical analysis of bicycle frame breakage but more as a way of saying “frame breakage is rare”.
Even in a rather small community like bicycle touring, a thread like this that reports 6 frame breakages shouldn’t be taken as a sign that frames break with any regularity. While I have broken 4 frames, I’ve owned 40 bikes, 36 of which
haven’t broken. Even at a 10% failure rate, I don’t think that bicycles are particularly prone to breakage. I consider all but one of the breakages due to engineering and manufacturing errors. Using a Hell Bent seatpost with about 2” of setback on my Flashback was my fault.