We are going to talk about how to remove a crank set on the most basic crank, which is a square taper, basically a square taper bottom bracket with a crank that fits onto that. This bicycle went across country. It belongs to one of our customers who went from Brooklyn to Portland, so it needs a lot of work and the crank, the chain ring, which are the teeth here, are all worn out so we are going to replace this crank.
To do that, for this bike you need an 8mm hex or Allan wrench. On some bicycles, especially older ones you will see the bolt right here, which is called a crank bolt, is a 14mm or 15mm socket wrench. We have to take these crank arm bolts off and to do that we are going to use the 8mm, 'righty tighty lefty loosey' on both sides. They may be torqued down really hard as you can see, especially with all of those miles. It probably has a lot of dirt and grime on them. There is one. I will take off the other.
After you have both crank bolts off, and make sure that there are not any washers inside, you are going to take your crank arm remover and it could look like this or it could look a little different. There are all different types. Make sure that it is for a square taper crank and bottom bracket. You are going to thread it on with your hands, just like you would with your pedals to make sure that you are not cross threading it. Thread it on as tight as you can possibly get it. Then use a wrench to make sure that it is nice and tight.
So this outside piece that is sliding back and forth also has threads on it. Basically, it is a pin and it is going to push on the bottom bracket and it is going to pull these threads and pull the crank arm off. While you are doing this you should see the crank arm actually coming off. If you do not and it is really, really tough, usually there is something wrong like there is a washer inside or you forgot to take off the bolt or something like that. You want to make sure that when it is pulling it off that it is not pulling out these threads. You have to make sure that there are enough threads inside there because you are using a lot of force.
There you go. Your crank arm is pulled off and you can take your wrench, take off your tool and start on the other side.