Originally Posted by A10K

I find this disconnect a lot at the community shop where I volunteer. People come in asking "Do you have replacement gears for my Mongoose" or "Do you have a handlebar thing (stem?) for a Trek?" A lot of people think bikes are like cars or consumer appliances, where every part is unique to the unit/brand. In reality bikes tend to be horizontally interchangeable; parts are the same across similar models/niches of different brands and less so between different types of bikes in a single brand. This modularity is part of the magic of bikes for me; there's a few different mechanisms that work pretty much the same across all bikes.