There are a number of different ways to learn how to repair a bicycle, either for the maintenance of your own bike or to help out friends. Many people find that reading a book or looking online can give them the information they need. Others take a class or learn on the job, at a sales or repair shop.
Perhaps the quickest method to getting the hang of bicycle repair is to head to a library or bookstore and pick up a book on how to repair a bicycle. Most of these types of instructional books come with step-by-step descriptions that are accompanied by illustrations. You also will learn early on what type of tools are needed to maintain and repair your bike. In addition, there are many online videos and informational web sites that will provide similar information.
The advantage of these methods is that you can learn how to repair a bike on your own time schedule, devoting as much or as little time to the endeavor as you can. You can pick up a used bicycle to practice on as you go through various projects outlined in the bike repair material or site. This type of learn by doing activity works well for people who tend to retain information by walking through the steps personally, rather than memorizing what they see or hear.
Another option is to look into classes at the local vocational or trade school. As bike riding has become more popular the last few years, courses in how to repair a bicycle have become more common. Generally, these classes are short-term, with six to eight sessions to attend. This is an ideal option for anyone who wants to learn bike repair, but would feel more comfortable doing so in a group setting.
A third option is to learn how to repair bicycles by getting a part time job at a bicycle shop. Here you can learn all about making the usual adjustments, performing bike maintenance, changing out tires and tubes, adjusting or replacing brake pads, and all the other small details. The bonus to this type of learning situation is that experienced coworkers can interact with you on a one-one-one basis, much like a mentoring situation. This casual approach will teach you a lot about bicycles, and also let you earn a few extra dollars at the same time.