The bike bottom bracket is one of the most important piece of part in any bike and it is the part that connects the crank arm to the frame of the bike. Different types of bottom brackets can have different sizes, but the important thing is to understand how the bottom bracket works and how it can be removed without any tool.
Removing a bottom bracket is a fairly straightforward process, but unfortunately, there’s no such thing as a “standard” bottom bracket. There are lots of different kinds that use different tools, so you’ll need to be familiar with whatever type of bottom bracket your bike has.
The most common types of bottom bracket are Shimano (made for use with a Shimano tool), Octalink (made for use with an Octalink tool), and ISIS (made for use with an ISIS tool). Unfortunately, there are no “universal” tools for these types, so you’ll need to buy the correct one for your bike.