Removal of Headset cap?
06-08-07 | 09:23 AM
#1
Thread Starter
Junior Member
Joined: Jun 2007
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Removal of Headset cap?
Greetings, You know like most things thirty years ago as a kid when I was tearing bikes apart they seemed much simpler. Not as cool, but simpler.
I want to replace the headset cap with a personalized one for my wife on her Giant FCR bike. It's a threadless head set, I know that much, but someone told me the allen screw holding the cap down at the top is loaded, and should not just be unscrewed... True? If so, anyone have any reccomendations as to the removal and replacement for proper installation?
Thanks,
I want to replace the headset cap with a personalized one for my wife on her Giant FCR bike. It's a threadless head set, I know that much, but someone told me the allen screw holding the cap down at the top is loaded, and should not just be unscrewed... True? If so, anyone have any reccomendations as to the removal and replacement for proper installation?
Thanks,
06-08-07 | 09:26 AM
#2
You Know!? For Kids!
Joined: Apr 2005
Posts: 6,166
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From: Just NW of Richardson Bike Mart
Bikes: '05 Trek 1200 / '90 Trek 8000 / '? Falcon Europa
The cap on a threadless headset is used to set the preload on the headset bearings with the stem bolts loose. Once the stem is tighted, the headset cap can be loosened. If all you are doing is changing the cap and you have not loosened the stem, you have no worries. Change away!
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06-08-07 | 06:55 PM
#5
It's an old photo
Joined: Aug 2006
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From: Entropia
Bikes: Cannondale R500, Specialized Hardrock
See where your wrench is positioned before you loosen it, then turn anticlockwise about 1/2 to 3/4 of a turn.. at this point there should be no resistance (in the bolt, not the headset). Then turn the bolt clockwise until it just starts to have resistance (should be relatively obvious). Now compare this position with your original position, and this is approximately how much you should torque it when you reinstall it (probably about 1/2 a turn).
It's not that important, but if someone inexperienced loosens up the stem for whatever reason (becomes crooked in a collision, etc.) then the preload on your bearing could become way loose or way tight depending on how you torqued it in this step. Most experienced mechanics will check the headset after adjusting the stem clamp anyway, but it's always good to be careful. It'll take you 30 seconds longer.
Alternatively you could actually loosen up the stem and adjust your bearing pre-load to get some idea of how it should be done.. but really it's a little bit much for a top-cap installation.
It's not that important, but if someone inexperienced loosens up the stem for whatever reason (becomes crooked in a collision, etc.) then the preload on your bearing could become way loose or way tight depending on how you torqued it in this step. Most experienced mechanics will check the headset after adjusting the stem clamp anyway, but it's always good to be careful. It'll take you 30 seconds longer.
Alternatively you could actually loosen up the stem and adjust your bearing pre-load to get some idea of how it should be done.. but really it's a little bit much for a top-cap installation.
06-11-07 | 06:08 AM
#7
Non Tribuo Anus Rodentum and off to the next adventure (RIP)
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With the stem bolts loose, you tighten the cap bolt enough to take the slack out of the headset bearings without causint the bearings to bind.
How do you tell?
With the wheels on the ground and the headset stack all lined up and seated, tighten slowly till a small change in resistance if felt. Lock up the front brake and gently rock the bike bach & forth. If movement in the stack is felt tighten the top cap bolt some more and re check. Repeating as needed till the movement is gone. Now lift the front of the bike and rotate the forks from side to side and check for smooth rotation. If it feels rough or stiff, slacken the top cap bolt until you achive balance. If you can't, the headset bearings probably need attention.
How do you tell?
With the wheels on the ground and the headset stack all lined up and seated, tighten slowly till a small change in resistance if felt. Lock up the front brake and gently rock the bike bach & forth. If movement in the stack is felt tighten the top cap bolt some more and re check. Repeating as needed till the movement is gone. Now lift the front of the bike and rotate the forks from side to side and check for smooth rotation. If it feels rough or stiff, slacken the top cap bolt until you achive balance. If you can't, the headset bearings probably need attention.
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06-11-07 | 06:25 AM
#8
Curmudgeon
Joined: Aug 2005
Posts: 1,572
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From: Nausea, New Hamster
Bikes: (see https://wildavis.smugmug.com/Bikes) Bianchi Veloce (2005), Nishiki Cascade (1992), Schwinn Super Sport (1983)
Originally Posted by msksoccer
Can you expand on how to pre-load the bearings in the headset if at some point in time I wanted to swap out the stem with one of a different length? What is involved?
- Wil
