Hello everyone, my first post here!

I've had my bike for several years, and the low height of the handlebars has always annoyed me, i get some back pain bending forward to reach them. I'm long overdue for raising them up a bit.

Although its not the same brand, my handlebar system is functionally identical to this bike:
youtube.com/ watch?v=-iBe1j-cxH4

(it wont let me post links properly, remove the space)

I've spent the past few hours taking it apart and learning how it works, its basically the same as that. Same threading on the wedge, same depressed stem bolt that goes down to it, same nut on the outside, etc. so that gives you a visual aid of what i'm working with.

Oddly enough, i'm lucky to have two copies of the same bike. Because my flatmate has an identical bike to me (same brand, same model, even same colors) so i've been comparing the two to figure out some differences. His bike is a couple years newer than mine.

Anyways, down to business. One problem i've noticed, is that the wedge in my bike seems to be fixed inside the fork. But on his, it's mobile, can be taken out. When i slide it back in it stops at a certain point where the fork narrows.

So the problem:
1. Which of these is correct? Is the wedge supposed to be stuck inside the fork, or should it be removeable? I'm leaning towards the latter. Maybe mine is just rusted in?

2. Assuming the wedge IS meant to be removable, what will stop the handlebars from sliding downwards if the wedge is anywhere but the bottom? say, if the rider leans on them a bit. This seems to be a problem that worries me when raising the handlebars up.
The stem bolts are not long enough to reach the wedge if the stem is raised upwards more than 1cm

Is the constriction of the external nut meant to be enough to prevent the stem sliding downwards?
Or do i need to get a longer stem bolt to be able to raise the stem up?

Also a related issue:
Before i started messing with things, my friend's handlebars were already raised up - considerably. Almost 3 inches higher than mine. However this didn't seem to be working out so well, and he was having some occasional problems with the stem turning inside the fork (and thus, the front wheel not turning) under high force. What could cause this?

The wedge is part of the stem, and should move with it as you adjust the stem height.

The wedge jams the stem against the inside of the steer tube so it can't move, provided you tighten it sufficiently.

That's because the wedge moves with the stem. If yours doesn't move, it's because it has corroded into place. Removing it can be a chore. After successful removal, use plenty of grease or anti-seize compound to prevent it from happening again.

https://www.sheldonbrown.com/brandt/stuck-stem.html

The stem should be marked with a "minimum insertion" mark. Don't raise the stem beyond this mark. And make sure that the stem bolt is tightened sufficiently to hold securely.

Yes, it sounds like yours is rusted in place. I would put your stem back in, and see if you can't get the bolt threaded back into the wedge. If you can, tighten it up. Then, loosen the bolt about 3 turns. You want to keep the bolt threaded into the wedge. Then take a rubber mallet or a hammer cushioned with a block of wood or something and give a few quick raps on top of the stem bolt. This will likely "unstick" that wedge so that you can pull it out (as it's still threaded into the bolt). It will likely be very rusty -- give it a good coat of grease before putting it back in.

The previous poster is absolutely correct regarding observing the "minimum insertion" markings on the stem. You can raise the stem up to that point, and no higher. If you want your handlebar even higher than it is at that point, then you'll need to buy a taller stem. They're not that expensive ($15-30). Bring your current stem with you to your local bike shop and they can get you the right sized replacement.

with bolt still in wedge, but loosened until a little proud above the stem, a tap with a hammer on the end of the bolt, is how they are loosened.


removing the wheel the fork steerer is a open tube, so if the stem is out but the wedge is still there,
you, with a long punch and that hammer, can approach it from beneath..





....

Be careful with maximum insertion too. Some headsets narrow a bit toward the bottom, so the wedge can't properly grip the sides when the stem is fully lowered. Had that issue with one of my bikes and couldn't get the handlebar low enough to suit myself. Easiest solution was to swap from the riser bar to flat bar. Problem solved.

Here is a article with a diagram which shows what Canklecat is describing. https://www.sheldonbrown.com/handsup.html#danger


You will want to tighten the wedge bolt enough that you cannot rotate the stem with moderate pressure, but not so tight that it cannot move at all, so that you are less likely to be injured by the bar in a crash. Do this with brake and shift levers as well, to lessen chances of damage as well as injury.

Drastically raising, there is a tube quill stem raiser, a chromoly steel tube the stem goes into, that in turn goes into the fork.