I am going to show you how to take a part and reassemble headsets, also to adjust them as well. This of course, is a threadless headset; this is the standard on mountain bikes now and has been for at least 1990 or so. You have a top cap that you have to remove in order to get the stem off. The stem holds the headset and adjustment on threadless system is pinch bolts clamping it on there.
What' s going to happen is the forks are going to fall out, we are going to remove that stem, you notice that the brake hose is connected so I am going to have to disconnect the brake hose, the fork can come out freely. It's all there is to that, keep the bolt here, okay so the brake is free. Now the forks are going to be able to come free and we kind of progressively unscrew, work the other one. Both stems have both bolts coming from the same side, usually from the drive side and now the fork is out. You can now see the nut is inside there, that's what the top cap bolt threads into. This is the crown race, fork crown race, where the bearings roll down here and this is the headset. In this case, it's called the top cone, generally, a bearing cup is cup shaped and the bearing roll on it and then the cone is cone shaped.
To remove the headset, you need this tool which, it’s a RT-1. Okay, so you pull it into the point where those prongs spring apart and then that is going to push against that. And now you can see that's how pushed out the headset cup and then you drop it on the other way. And generally, this goes flying unless you catch it, see that goes flying.
So we can see a couple of things about a head tube that's critical. The top surface and the bottom surface, the end surface is where the head tube have to be milled exactly parallel to each other. So to remove the crown race, that's and to install it is in another section in this DVD with a different fork. But you can see that here there is notch in front and back that you would put your screwdriver in to drive it off.
First thing when you are installing a headset is to grease the inside of the head tube at the end, just the rim section where the cups are going to go. And then you need a press to press the cups in, this is a park tool, you push this spring release, it clips into various notches for different length, head tubes. So you slide that off first, then there are these two pieces that center the headset parts.
Some headsets, you don't actually want to use these because that will be pressing on the bearing and this would be one of those cases. So instead, we are going to use the flat surface here and headset will sit like that, we will press it in that way. This particular headset, there is no difference between the top cup and the bottom cup.
Generally, that's not true, usually there is a difference in size or difference in orientation of the bearing or something and usually the bottom cup, you will know because it will have the manufacturers logo on there and if you want to read it right side up, it will be clear which way to put it. So the cup there, slide that in then slide this cup up, hold that in place and then the bottom, park snaps in, make sure it's snapped into the one of the notches. Then you start turning this until you get everything in the contact and then once it's in contact, you want to make sure that these end pieces up are centered on the headset, you don't want to be pushing for instance like this with this thing off to the side or something.
When you are using this external end plates to push the cups in, you can certainly press too hard with one of these and actually bend these edges and you just want to go snug, make sure, and now you can see grease kind of squeezing out and it's pretty good there. If I didn't have bearings in there and I was using this insert on either end, I could go as hard as I want and I wouldn't have to worry about crushing anything but in this case, you can certainly crush the cups so you want to be sensitive to that and avoid doing that.
Now I am ready to put the fork and I will put a little grease around here and you really
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