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How much abuse can a carbon fork take?

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How much abuse can a carbon fork take?

Old 03-02-08, 04:24 AM
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How much abuse can a carbon fork take?

I just built up my first road bike (after a few years of riding a hybrid), and it has a carbon fork. A Kestrel EMS Pro OS with an aluminum steerer.

I'm wondering how I can treat this fork. On my hybrid, with a steel fork, I would just ride off curbs and over speed bumps without thinking twice. I always make an effort to "ride light" when I do that sort of thing, but I'm wondering if a carbon fork can take that kind of riding.

The other day I rode off a curb with it by accident (after my headlight died...) and everything was fine, but I half expected it to snap like a twig.

I'm probably nervous for no reason, if carbon is good enough for cross, it is probably tough enough for the occasional curb or speed bump.

So how much can these forks actually take?
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Old 03-02-08, 04:53 AM
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A lot.
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Old 03-02-08, 05:52 AM
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Originally Posted by roadwarrior
A lot.
+1 No problems here either...even with a CF steerer.
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Old 03-02-08, 06:17 AM
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Short answer: nobody knows:
https://www.ntsb.gov/ntsb/brief.asp?e...08X05209&key=1
About ten minutes into the flight, the pilot initiated a pull toward the vertical with about 360 km/hr and 7 Gs, according to witnesses. This would have been well within the maximum airspeed and load specifications of 450 km/hr and 10 Gs, respectively. The right wing of the airplane separated during the pull up. ... Testing of the wing spar was performed by the NTSB and MAK (Russian Investigative Authorities). Both agencies found numerous voids in the composite spar caps. The investigation revealed evidence that the curing process for the wing spar did not provide adequate vacuum pressure. There was evidence that during the curing process, the fibers separated from each other, which resulted in voids in the final composite material.
But Sukhoi makes jets, not bikes, so it's probably fine.
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Old 03-02-08, 06:18 AM
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It takes a head-on collision at about 25mph to break one. Don't ask me how I know.
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Old 03-02-08, 06:47 AM
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Originally Posted by zacster
It takes a head-on collision at about 25mph to break one. Don't ask me how I know.
how do you know?
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Old 03-02-08, 08:27 AM
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I would worry more about my wheels than my fork if I was jumping curbs. Don't worry about the fork, especially with the aluminum steerer, you will be ok. Nice bike, congratulations!
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Old 03-02-08, 09:03 AM
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No worries; though I don't make it a habit, I do go up/down curbs on occassion. No explosions yet.
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Old 03-02-08, 09:17 AM
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my buddy commuted on a track bike with carbon forks for about a year and had no problems...
till he did a wheelie two weeks ago and landed with the front wheel perpendicular and cracked it. he wasn't going that fast either.
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Old 03-02-08, 09:24 AM
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They make full carbon mt bikes. They make full carbon cyclocross bikes not to mentionn full carbon being raced in the pro pelaton. I dont htink a drop off a curb is going to hurt anything.
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Old 03-02-08, 11:20 AM
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It wont last you as long as a steel fork but it should be fine. If you crash then that should raise concern.

Carbon fiber won't last as long as steel. It won't take a hit like steel, but you can abuse it...Just don't crash it. If you crash it then it could be damaged.
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Old 03-02-08, 11:35 AM
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Originally Posted by SoreFeet
Carbon fiber won't last as long as steel.
That remains to be seen.....there are alot of factors that will destroy steel faster than CF...ever seen CF rust?
Originally Posted by SoreFeet
It won't take a hit like steel, but you can abuse it...Just don't crash it. If you crash it then it could be damaged.
This is misleading....CF is very strong, i'm not a materials engineer but i suspect it can take the same, if not more, force as steel, steel just happens to let you know before it fails by bending. I also suspect that a large number of CF failures have more to do with their particular construction process rather than the material itself.

whatever you do never leave CF in the back of a car on a hot day, you're likely to destroy a whole city block
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Old 03-02-08, 12:25 PM
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Originally Posted by pcates
That remains to be seen.....there are alot of factors that will destroy steel faster than CF...ever seen CF rust?

This is misleading....CF is very strong, i'm not a materials engineer but i suspect it can take the same, if not more, force as steel, steel just happens to let you know before it fails by bending. I also suspect that a large number of CF failures have more to do with their particular construction process rather than the material itself.

whatever you do never leave CF in the back of a car on a hot day, you're likely to destroy a whole city block
strong, but brittle.
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Old 03-02-08, 12:30 PM
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Originally Posted by SoreFeet
It wont last you as long as a steel fork but it should be fine. If you crash then that should raise concern.

Carbon fiber won't last as long as steel. It won't take a hit like steel, but you can abuse it...Just don't crash it. If you crash it then it could be damaged.
Thats poppycock.

A steel fork is just as vulnerable in a collision as carbon because it can bend. Carbon has similar flex it will just crack.

To the poster... I've been hit by a car 3 times on my road bike. Had my carbon components tested each time and all are within spec. But again... it depends on the situation. Although... all 3 times were pretty good licks.
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