Replacing a stem

[TheJackal]

Have read loads and loads of posts describing replacing/servicing headsets but never anything on replacing a stem!!! That either means it's so easy that it's not worth worrying about, or ...!

I have a Chris King NoThreadset and a "normal" stem. I wish to replace the original stem for a shorter one.

I understand that the top cap on the headset needs to be loosened but if I completely take it off and then undo the stem pinch bolts surely the steerer will just come loose and the forks drop out?

Also if I were to do the above what would happen to the star-fangled nut, that's supposedly inside the steerer?

[xerxes]

Quote:I understand that the top cap on the headset needs to be loosened but if I completely take it off and then undo the stem pinch bolts surely the steerer will just come loose and the forks drop out?

That's exactly right, the stem should just slide up and off the forks; you don't really want to let the forks drop out incase the bearings fall out. The star fangled nut should be secure and remain in the fork steerer tube.

[TheJackal]

(07-18-2010, 05:14 AM)xerxes Wrote:  

Quote:I understand that the top cap on the headset needs to be loosened but if I completely take it off and then undo the stem pinch bolts surely the steerer will just come loose and the forks drop out?

That's exactly right, the stem should just slide up and off the forks; you don't really want to let the forks drop out incase the bearings fall out. The star fangled nut should be secure and remain in the fork steerer tube.

Many, many thanks, albeit belatedly.

[Surly LHT]

You can do this while the bike is on the ground no need to have it on a repair stand for this.

[JonB]

Quote:I understand that the top cap on the headset needs to be loosened but if I completely take it off and then undo the stem pinch bolts surely the steerer will just come loose and the forks drop out?

actually, there's a compression ring in headsets that means you generally need to give a steerer a bit of "encouragement" (read: use a tapping stick) to come out of the frame, and with Chris Kings being really good quality this will certainly be the case. Some cheap headsets will allow the steerer to just fall out of the frame, but not this one! (Kings aren't cheap by a long way).

To replace your stem just simply take the top cap off completely, undo pinch bolts on stem and pull. It should just slide off (though some are harder to slide than others, the one on my DH bike needs extra "encouragement" sometimes, even with the pinch bolts completely removed). Push your new one back on and put the top cap back on, then adjust the headset before finally tightening the pinch bolts on the stem.

(don't forget to put your bars on the new stem )