Bicycles Stack Exchange is for people who build and repair bicycles, people who train cycling, or commute on bicycles.
Most questions regarding bicycles, tricycles, unicycles, handcycles, and their use are on topic for this site.
Questions seeking product, service, or learning material recommendations are off-topic because they tend to become obsolete quickly. Instead, describe your situation and the specific problem you're trying to solve.
If you're not quite sure if your question is on topic, consider looking at meta questions tagged [on-off-topic] where the community has discussed what questions are appropriate for this site. For more help, see "What types of questions should I avoid asking?"
If your question is fairly basic, you might find the answer in one of our growing reference pages. Also, feel free to link to these in your questions and answers, particularly the entries in the terminology index if you'd rather not re-invent the two-wheeler.
If your question is not specifically on-topic for Bicycles Stack Exchange, it may be on topic for another Stack Exchange site. If no site currently exists that will accept your question, you may commit to or propose a new site at Area 51, the place where new Stack Exchange communities are democratically created.