Okay, so we're going to talk about different types of crank sets. In a future video we will look at how to install and take off crank arms that go in a square taper bottom bracket, which is one of the most common. Cranks now, for example, this bike, a lot of cranks are switching to outboard bearings, so basically where the bearings are outside the actual frame. So as you can see, this is an outboard bearing bottom bracket.
Basically what that means is not like a square taper where the bearings are inside the actual frame. Their inside a, inside a cartridge inside the frame. The bearings are outside. So what that does is it basically makes, it allows it to have larger bearings, it's also much stiffer, and you can tell pretty easily that this is outboard bottom bracket. If you look at a square taper bottom bracket, or something else like an Octalink or something, you can usually see the actual bottom bracket axle protruding out.
This you can't at all, because the axle goes from the crank with the chain rings over here, all the way through over to the arm where it connects with this star nut, and with the hex keys. It just makes it stiffer, it's a little more expensive, it's kind of where a lot of the modern real bikes are going if they are not going to BB30 which is even more expensive and stiffer bottom bracket system.
There's also other types of cranks and bottom brackets, like Octalink, Power Spline, things like that. So you want to make sure that when you are servicing your bottom bracket and your cranks, that you are using the proper tools according to which crank you have by which manufacturer, and to their torque specifications.