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Old 08-26-07, 06:27 PM   #1
sbskates
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carbon steerer vs alloy on road forks, thoughts?

i just bought my first carbon fork. i wanted one with an alloy steerer but i went for the all carbon. anyone have any thoughts on carbon steerers. are they trouble some when tighteneing stems? fears of cracking steerer? or as i know one person the bung plug kept slipping up on his specialized. should i send it back and get alloy ?
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Old 08-26-07, 08:52 PM   #2
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I snapped off a carbon steerer when I pulled up on the bars to get going up a steep hill. The steerer snapped off at the stem.
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Old 08-26-07, 09:54 PM   #3
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1. Do be careful when tightening the stem. Like carbon seatposts, if you overtighten, they will crack.

2. If you want to a few inches, or more of spacers, you should go with alloy. Carbon steerer tubes cannot have too much exposure above the head tube. For instance, Cannondale's forks with carbon steerer tubes, which probably match up with any on quality, specify no more than 40mm of spacers beneath the stem, and none over the stem. There's no such limitation on aluminum steerer tubes.
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Old 08-26-07, 10:23 PM   #4
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Carbon fiber forks are a finite component. You can enjoy a light product at the expense of saftey. For the price of the lightest Easton all carbon fork you could likely get a full custom titanium fork and not have to worry about cracking your fork. Friends don't let friends ride carbon. I don't care how good the lab results show carbon to be it is not a product that can be ridden the hell out of.

To answer your question...Do not worry about having an all carbon steer. Use the recommended maximum amount of spacers and don't go beyond that. Be very careful when you clamp your stem, don't over do it. Have your LBS use a torque wrench if you don't have one.

Ride and enjoy. Just remember that your carbon fork should not be ridden for 20+ years like a good old fashioned steel fork. On paper your carbon fork might exceed 200,000 cycles of fatigue but that means nothing considering general road wear and tear such as rocks/gravel flying up hitting the fork.

Unless you have an electron microscope there is no accurate way to detect defects/structural damage in your carbon fork. It is your life go ahead and gamble it on a plastic fork.
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Old 08-27-07, 11:23 AM   #5
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Carbon scares me.
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Old 08-27-07, 01:45 PM   #6
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Call me old fashioned, but I just can't see myself using a plastic steerer tube.

If you do insist on using a plastic steerer, ensure that there is steerer protruding above the stem with a spacer to cap it off. Not doing so can result in the stem "pinching" assymetrically and crusing the top of your plastic steerer.
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Old 08-27-07, 03:48 PM   #7
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titanium fork????????

where do i get a titanium 1 1/8 fork?
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Old 08-27-07, 06:08 PM   #8
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Call me old fashioned, but I just can't see myself using a plastic steerer tube.

If you do insist on using a plastic steerer, ensure that there is steerer protruding above the stem with a spacer to cap it off. Not doing so can result in the stem "pinching" assymetrically and crusing the top of your plastic steerer.
Check the instructions and specifications on the fork you buy. Many warn against doing what is suggested above.

Some fork manufacturers include a top cap, a portion of which protrudes into the steerer tube, which serves to support the area over which the stem is clamped, preventing crushing.
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Old 08-27-07, 06:44 PM   #9
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Unless you have an electron microscope there is no accurate way to detect defects/structural damage in your carbon fork. It is your life go ahead and gamble it on a plastic fork.
Bah!

Yeah, and aluminium steerers never, ever shear, steel never fatigues and Ti never fails.

I guess those guys at Airbus are really gonna get it when their new planes start falling from the sky. Or maybe they've hired a few hundred guys with electron microscopes to go over every inch of the plane every time someone drops a glass on the floor or bangs their luggage against something.

I've raced on carbon for YEARS and, as long as you don't overtighten the stem, it will be fine. If you crash, like you would with ANY fork, you should look for gouges and cracks. If there is damage, you will hear it under load (kinda like aluminium when it is about to fail, non?)
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Old 08-27-07, 09:46 PM   #10
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Carbon scares me.
This is a little off topic, but I was reading Time magazine and there was an article about prosthetics for animals (dogs, kangaroos, elephants, etc.) in which it stated that carbon fiber is an excellent material to use for leg prosthetics for animals because it is bends,but doesn't break and retains its shape after flexing (in reference to a leg prosthetic for a kangaroo - Time also noted that the "famous" amputee athlete - runner, I guess - uses CF prosthetics for sports).

Also I've heard CF is used in planes and space shuttles and such. I also remember the tensile strength numbers of carbon nanotubes (used in some bike stuff, I think) rivaling that of steel (from some show on Discovery Channel).

Either the CF is grossly different for biking applications or us bikers are way wrong because CF scares me too.
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Old 08-28-07, 02:19 AM   #11
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This is a little off topic, but I was reading Time magazine and there was an article about prosthetics for animals (dogs, kangaroos, elephants, etc.) in which it stated that carbon fiber is an excellent material to use for leg prosthetics for animals because it is bends,but doesn't break and retains its shape after flexing (in reference to a leg prosthetic for a kangaroo - Time also noted that the "famous" amputee athlete - runner, I guess - uses CF prosthetics for sports).

Also I've heard CF is used in planes and space shuttles and such. I also remember the tensile strength numbers of carbon nanotubes (used in some bike stuff, I think) rivaling that of steel (from some show on Discovery Channel).

Either the CF is grossly different for biking applications or us bikers are way wrong because CF scares me too.
Everything you mention is true. You can dictate the characteristics of the item you are building based on how you "lay up" the carbon layers. You can make something that flexes in one direction but won't flex at all in another. This is why it is particularly good for bikes. You can create something that is both stiff AND comfortable.

The problem, for cycling, is that carbon tubes don't respond well to clamping (or crushing) forces so things like clamping a seatpost/stem/bar/fork can be problematic of they are over tightened. As long as you address this factor (which isn't hard to do) then carbon is very strong and durable.
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Old 08-28-07, 06:43 AM   #12
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Why do people ALWAYS bring up the airplane argument when talking about carbon. When the bicycle component industry is as scrutinized as the airline industry, please come back and talk to us.
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Old 08-28-07, 06:50 AM   #13
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Why do people ALWAYS bring up the airplane argument when talking about carbon. When the bicycle component industry is as scrutinized as the airline industry, please come back and talk to us.
When a bicycle undergoes the kind of stresses an aircraft does it will be worth the scrutiny.

Meanwhile, I'm tired of people yelling that the sky is falling. There are millions of carbon parts in use right now. Today. Where are all these catastrophic failures I keep hearing people talk about?
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Old 08-28-07, 09:13 AM   #14
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What is the lightest carbon fork with aluminum steerer out there? I think the Ritchey Comp is 460g.
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Old 08-28-07, 10:49 AM   #15
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How much lighter does a carbon steering tube actually make the fork? Is it really noticeable? I'm not talking grams either. If you are looking for peace of mind, why not use an aluminum steering tube.

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Old 08-28-07, 02:06 PM   #16
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Check the instructions and specifications on the fork you buy. Many warn against doing what is suggested above.

Some fork manufacturers include a top cap, a portion of which protrudes into the steerer tube, which serves to support the area over which the stem is clamped, preventing crushing.
A good steering tube plug will have that same portion so that when the stem is tightened the CF steering tube will be sandwiched between metal.

I found some Weyless brand at Performance that work REALLY well and of course were on sale.
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Old 08-28-07, 02:42 PM   #17
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Absolutely. Carbon is not safe at all. It's only good for non-safety critical applications like commercial aircraft and Formula 1 cars.
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Old 08-28-07, 05:20 PM   #18
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How much lighter does a carbon steering tube actually make the fork? Is it really noticeable? I'm not talking grams either. If you are looking for peace of mind, why not use an aluminum steering tube.
I have complete piece of mind with the carbon forks I am using and have been for the last 10 years or so. I have that but not the 80-100 grams extra weight on my fork that an aluminium steerer would add.
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Old 08-28-07, 06:03 PM   #19
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Oh on top of what I said earlier, I remember when I was a teen a couple of years ago and into those silly little street racing cars that there was this amazingly fast Mitsu Lancer EVO with the chassis entirely made of CF. I remember it crashed at a very high speed into whatever they use to to line up test tracks (hay stacks maybe?) and the car wasn't damaged that badly.
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Old 08-28-07, 06:14 PM   #20
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Absolutely. Carbon is not safe at all. It's only good for non-safety critical applications like commercial aircraft and Formula 1 cars.
i'm no expert on carbon, but have you ever watched an F1 race? have you seen how the carbon front a-arms shatter when in an accident? in the old days, the steel and aluminum ones would bent while carbon tends to shatter into a million little pieces. why? carbon fibre can take a much higher stress load than steel and aluminum, but only in certain directions. in a F1 car, the forces that act on the a-arms are vertical loads, (picture the capital letter A with a wheel at the top of the letter, that's a bird's eye view of the wheel and A-arm), and thus the carbon rods are made to endure high stress in that direction. when a car is involved in an accident, and forces are applied to that same wheel and a-arm in an horizontal direction, the carbon a-arms splinter into thousands of pieces as the carbon isn't made to handle stress applied in a horizontal direction.

how this applies to bikes, i'm not really sure...
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Old 08-28-07, 06:49 PM   #21
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What is the lightest carbon fork with aluminum steerer out there? I think the Ritchey Comp is 460g.

I'd opt for Reynolds Ouzo Comp. It's the same as the Pro, but with and Al steerer; so it's better than rock solid?

Weight shmeight
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Old 08-28-07, 07:35 PM   #22
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i'm no expert on carbon, but have you ever watched an F1 race? have you seen how the carbon front a-arms shatter when in an accident?...the carbon a-arms splinter into thousands of pieces as the carbon isn't made to handle stress applied in a horizontal direction.
It's all in how you lay it up. You can decide which way you want the carbon to flex and which way you want it not to flex. You can make it so that it handles load in all the critical directions but fails (thereby dissipating energy) during an F1 crash so that is reduces the impact for the driver (kinda like a crumple zone in your car).

For the bike industry, what you get from this is the ability to design a high modulus (stiff) frame that won't flex laterally under pedaling forces (at the BB and stays, for instance) but will be vertically compliant (at the seat stays, for example) thereby damping road shock and producing a more comfortable ride quality.

The key in all of this is that the people making it have to know what they are doing. In the early years of mass produced carbon parts, there were fewer people (and companies) that did. Now, there are several companies that have lots of experience working with this material and have figured out how to best use it.

These include, BTW, SEVERAL Taiwanese companies who also have production facilities in China. This includes Giant. Many of those carbon frames, forks and components (Scott, Willier, Kouta, Ritchey, Bontrager, Zipp, Specialized, litespeed, Cervelo and on and on) all come from these companies. So don't think it is only US and European companies that can make safe carbon.

Finally, a rule of thumb if you are worried about the quality of the carbon product you are drooling over. If the deal seems too good, the product probably isn't. There is no such thing as a cheap carbon part, not if it is made right.
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Old 08-29-07, 01:19 AM   #23
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I have complete piece of mind with the carbon forks I am using and have been for the last 10 years or so. I have that but not the 80-100 grams extra weight on my fork that an aluminium steerer would add.
So you saved approx 3 ounces, maybe 4. How much faster did it make you?


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Old 08-29-07, 01:42 AM   #24
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So you saved approx 3 ounces, maybe 4. How much faster did it make you?


Tim
Combined with all the other 1,2,3 or 4 oz savings very fast. So fast in fact, that I now carry a GPS with me because when I get to the top of a climb, I sometimes just keep going, up, up, up and often land several km away. The GPS comes in handy finding my way home.
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Old 08-29-07, 05:00 AM   #25
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Combined with all the other 1,2,3 or 4 oz savings very fast. So fast in fact, that I now carry a GPS with me because when I get to the top of a climb, I sometimes just keep going, up, up, up and often land several km away. The GPS comes in handy finding my way home.
But the extra weight of the GPS offsets the weight savings of the carbon steerer, so it's a wash. An expensive wash in fact.

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