Mikebike125 said:
I have a 2006 Trek 2100 and I noticed that the neck can be flipped over to get a lower position. I want to try that but I am not sure how to remove the neck. It has one center bolt going down the middle into the fork and two little bolts on the back of the neck (plus the ones holding the handlebars on) I have removed the handlebars but I am ussure as to which bolts to remove next. After that, what is the process to put this all back together and not have any play in the front fork??
Thanks!
BTW This fork is not threaded like the forks were back in the 80's
This mechanism is called a "threadless stem" as opposed to the ones "back in the 80s" that were called "threaded stems".
The part you're referring to is called the stem - it is the part that connects the handle bars to the "steerer tube". As you can see, the steerer is simply part of the fork.
In order to flip the stem you need to remove it from the handle bars and the steerer. In order to remove it from the steerer, you also need to remove the end cap.
Assuming you can see how all of this is done and can do it, just remove the end cap, take the stem off both the steerer and the handlebars, flip it over and reattach it to the handlebars. Be careful not to over tighten, but if you don't tighten enough, the handlebars will move if/when you put weight on them and/or go over a bump in the road.
Then, you loosely attach the stem back onto the steerer. Loosely. Then insert the end cap bolt into the little "star nut" that is lodged inside the steerer. As you tighten the end cap bolt, this will tighten up the bearings in the head tube (the part of the frame that the the steerer goes through). You tighten up the end cap enough so that the fork does not wiggle at all, but again, don't over tighten. You'll have a chance to tighten some more if necessary, but just tighten it enough so that it does not wiggle. The end cap bolt simply draws the steerer bearings upward against the races they seat on so they seat firmly, aren't loose, but aren't so tight that they bind up. This is called "pre-loading the bearings". It's kind of a feel, but if you follow the steps below, it is really simple - a little trial and error at first, but it only takes a little time to get it right.
After you've "pre-loaded" with the center cap, then tighten the stem firmly to the steerer. Again, don't over tighten, but it needs to be tight enough so it doesn't move. This is also the point in which you'd make sure the handle bars are aligned with the wheel.
After you tighten the stem to the steerer, the end cap is not functional, except as a covering. The stem is now holding the bearings tight within the head tube.
Test the bearing tighness by straddling the top tube, hold the front brake real tight and push down and forward on the handlebars, trying to "flex" the front fork. If you feel any movement, the bearings aren't tight enough - not enough preload. If it is solid for this test and steers without any resistence, it is right on. If you've pre-loaded too much, you may feel the steering is tight or binding. That is unusual (in my experience); more common is that it's a little loose and you have to pre-load a little more....
Your rectify this by simply loosening the stem on the steerer and tightening the end cap some more - try 1/4 turn of the end cap bolt at a time. Re-tighten the stem on the steerer, and re-test the bearings as above.
Hope this makes sense. After you work through it, it realy is quite simple.
If you don't want to, it is normally a "while you wait" kind of thing for a bike shop and IF they charge you, it would be very minimal. Takes an experienced person just a couple of minutes.
