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Old 10-11-06, 11:24 PM   #1
urbanknight
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Fork flex?

As some of you know, I replace my damaged carbon fork with a "lightweight" steel one (Ritchey, about 670g) off ebay. After adjusting the play out of the headset, there seems to be noticeably more flex still than when I had the carbon fork. Just to make sure I don't have something else to worry about like a damaged head tube or a bad fork, this should be normal, right? I figure carbon should be stiffer than steel? If so, I'm happy to have an even more comfortable ride now. If not, I need to find out what's causing the flex!
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Old 10-11-06, 11:37 PM   #2
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I would carefully investigate. It should feel solid. Is it a threadless headset on a road bike or?
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Old 10-11-06, 11:44 PM   #3
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I would think any 670g steel fork would be quite flexy. Carbon is very very stiff, directionally, depending on how its layed up, so for forks its generally extremely laterally stiff and more vertically compliant. Steel, to get down to that 670g range is going to be pretty light and thin I would think, and steel is a fairly flexy material.
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Old 10-12-06, 12:08 AM   #4
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How are you seeing or measuring this flex to compare to before? Under braking? Leaning over in a sprint?
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Old 10-12-06, 03:46 AM   #5
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I generally find steel forks to be springier than carbon, except for those designed to have some compliance.
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Old 10-12-06, 06:28 AM   #6
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My Ritchey Road Logic frameset came with this steel fork installed. I have since replaced it with CF (lost the steel one to a car who rear-ended me with the bike in the trunk).

I could feel no ride difference at all. Both were pretty flexy. Watching the front hub as I ride over chipseal, the hub seems to move move back and forth 1/2" to 1" as the fork soaks up vibrations.
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Old 10-12-06, 11:22 AM   #7
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OK I should be fine then. I first noticed it when going down a hill and the front seemed to be more flexy, so I stopped and held the front brake while pushing on the handlebars a little. That was when I found too much play in the headset and tightened it. Now the test just shows some slight flex in the fork. I can't measure it that way, but I'm pretty sure I'm getting no more than the 1/2" described above (and it is a Logic fork). Maybe I just never paid attention to it before the crash, and am now paranoid over everything because I don't want to crash again. That's why I replaced the fork, the carbon one got lacerated by the spokes of a collapsing wheel and although the fork did not break, it's questionable as to what the lashing did to it.
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Old 10-12-06, 02:46 PM   #8
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Quote:
Originally Posted by urbanknight
OK I should be fine then. I first noticed it when going down a hill and the front seemed to be more flexy, so I stopped and held the front brake while pushing on the handlebars a little. That was when I found too much play in the headset and tightened it. Now the test just shows some slight flex in the fork. I can't measure it that way, but I'm pretty sure I'm getting no more than the 1/2" described above (and it is a Logic fork). Maybe I just never paid attention to it before the crash, and am now paranoid over everything because I don't want to crash again. That's why I replaced the fork, the carbon one got lacerated by the spokes of a collapsing wheel and although the fork did not break, it's questionable as to what the lashing did to it.
Steel is wonderful stuff. It can flex like that for decades.
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Old 10-12-06, 02:57 PM   #9
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^ Glad to hear, that means my butt should be able to handle a century now.
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