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Discussion Starter · #1 ·
As a mechanical klutz who normally has the LBS do everything on my bike other than inflate the tires (and sometimes that is a challenge), I would appreciate some help with what should be a pretty simple job.

The bars on my Trek 5500 are at a very slight angle to the front hub. I would like to adjust this. Are the steps involved as follows:

(1) loosen the bolts fastening the stem to the steerer tube;
(2) loosen headset bolt at the top of the steerer tube
(3) rotate stem slightly on steerer tube
(4) re-tighten headset bolt
(5) re-tighten stem bolts?

Have I reversed steps 1 and 2 or 4 and 5? Anything else I've missed? How tight should the bolts be re-tightened, especially on the steerer tube?

Also, on my other bike, I want to drop the bars a centimetre or so and move some spacers above the stem. Is the process essentially the same as the above, except that here I have to remove the top of the headset and the stem completely before removing the spacers? Again, anything I've missed? Any special precautions in tightening the stem bolts on a carbon steerer, other than, obviously, over-tightening the bolts and breaking the steerer tube? Anything special about tightening the headset bolt?
 

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I didn't think you had to losen the headset at all (on an integrated headset) just to make this adjustment to the bars. I thought you just loosen the stem bolts and leave the headset alone.

I hope that's ok, because that's how I've done it.

Also, adjusting an integrated headset with the stem bolts tightened has no effect, right?

I know nothing.
 

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Discussion Starter · #3 ·
I've now performed both operations, with apparent success. My only concern is the tightness of the stem clamp bolts on the steerer. (Yes, I know this is what torque wrenches were invented for.)

I have tightened the bolts just enough so that when, standing in front of the bike facing the handlebars, I clamp the front wheels between my legs, a modestly hard turn on the bars will not alter the angle of the stem. Is this sufficient? How much lateral force is the stem clamp exposed to? Will hitting a pothole twist the bars on the steerer? The bolts seem pretty tight and I'm not sure I would want to tighten them any further, especially on the carbon steerer.
 

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basically correct....

A minor change in the stem angle can usually be done, just by loosening the steering tube clamp bolts and mving the stem, while holding the front wheel between the legs. You shouldn't need to loosen the top cap.

The only thing I see missing if how much to tighten the top cap bolt, in order to properly adjust the bearings. Not all headsets require the same bolt tension. Some conventional headsets will bind with very little top cap tension, while integrated types require quite a bit more. One rough guideline is to tighten util there is some increased drag as the fork is turend, then back off the bolt 1/8 to 1/4 turn. The worst thing you can do is ride the bike with the headset bearings loose. The lower bearing race will be ruined pretty quickly.

As for moving the spacer from below the stem to the top, there is one possible problem. Carbon steering tubes always have an expansion plug to protect against possible crushing of the tube with the stem clamp. If the stem is dropped too much, the plug will be located above the stem and not be abel to do it's job.

If you're really mechanically inept, a torque wrench may be vital. The typical 5-7Nm (5-6 ft.-lbs.) torque on stem bolts is not a lot. Some folks easily over do it, breaking bolts or stripping threads in the process.

As far as actually crushing a carbon steering tube, it's really quite difficult. I've done my own tests by tightening a stem WAY too tight on a scrap piece of steering tube and never managed to cause damage. Just using short handled hex wrenches or a 4-5-6mm Y-style wrench will help keep the torque down.

Here's a link to park tool.

http://www.parktool.com/repair/readhowto.asp?id=65
 

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Discussion Starter · #5 ·
Thanks, C-40 - helpful as always. The steerer tube is going to need to be cut anyway after a month or so in the new position, so - if the fork survives that long after my tinkering - I will have it checked out at the LBS then.
 

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rossb said:
Thanks, C-40 - helpful as always. The steerer tube is going to need to be cut anyway after a month or so in the new position, so - if the fork survives that long after my tinkering - I will have it checked out at the LBS then.
If your fork doesn't survive this, then:

a) You are tightening the bolts to an insane degree. or
b) Your fork is made of glass.

Don't worry about it so much. Wouldn't you be more likely to strip something that destroy the steerer tube? That's an actual question, btw.
 
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