I don't think "broad" or "specific" are the right metric, and either is fine.
I'd ask instead:
How many people will have this exact question?
Will this help somebody in the future who has a problem and finds the post
by searching for their own question?
or more generally:
How many people will the answers to this question help out?
Really, most people have very specific problems that they'll be looking for answers to. They have a problem with that one bike right in front of them. They don't care about the general, only the specific problem they're actually having and looking for a solution to.
A question that's so specific that nobody else will ever have a similar problem and be helped by the answers to your question is probably too localized. But questions that super-specific are quite rare.
A specific question about that one bike right in front of you that could be similar to problems with other bikes is fine. I'd expect this to be the most typical question we'll get, in fact. The questioner includes the model of bike and the model of component and pictures of their actual bike and the answers help them solve their very specific problem, but somebody later with a similar problem on a similar bike with a similar component might see that question and answers and find their solution.
A general question with answers that would generalize to answer many specific questions is good, but hard to do. Generalizing a question often means leaving out important specific details. Details make questions easier to answer. Details make questions more easily found. Details make the question and answers more useful. Details may mean that you don't need to ask a followup question.
A question and answers that are carefully written to generally and definitively answer all similar questions of that type for all time are a beautiful ideal, but they're like unicorns: they don't really exist.
If we get similar (related) specific questions, they should have the same tags, which will get the other questions linked in the "Related" area on the right side of the question page. Explicitly linking (in a comment) to the other similar questions can be helpful, too.