Replies to This Discussion

Permalink Reply by Anand Kalelkar on November 16, 2011 at 9:40pm

If the chainlink had an official stance, it would be posted in the forum rules, which it is not.  I'd guess they are silent on the selling of used carbon bikes.

 

Personally, I don't think that used carbon bikes are anything like use helmets. Bike helmets are designed to withstand a single impact, ie a crash, once.  Then they need to be replaced.    Carbon frames/components are not engineered to be disposable.  If carbon was so delicate, there wouldn't be downhill mtb's made from it.  And it doesn't spontaneously explode, like some people believe. 

 

I've seen 20 year old carbon bikes being ridden successfully today, so I would not be afraid to buy a used carbon bike if no abuse or damage is evident.

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Permalink Reply by Doug Haynes on November 17, 2011 at 3:26am

Mark, after your completely ignorant statement in an another for sale thread and not this subject I have to ask; is it just your goal to be a complete troll or are you really this clueless about bike?

 

More importantly have you ever owned or ridden a carbon frame? 

 

Do you have any experience with, or knowledge about, carbon fiber beyond reading about it on the internet?

 

Unless you can answer both of those questions with a yes you probably need to shut up about the subject in general. 

 

Carbon is not unsafe and, most times, it is going to show signs of a problem before failure.  Not as much as a steel frame or fork but it still letting you know what is happening but before I get into posting a giant post I want you to answer a question for me first:

 

Why is carbon not safe?

 

I don't an answer that just says 'it can fail and stuff' like most idiots put up; you obviously know enough about this to feel qualified to push the management here about the subject so I expect a detailed response.  One that is going to involve real facts and knowledge of material specs; I'm not going to argue with repeating internet foolishness because anyone can re-post bad info give use some REAL knowledge or just admit you are hopping on a bandwagon.

 

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Permalink Reply by Doug Haynes on November 17, 2011 at 6:54am

Here is a better idea Mark, how about you tell us why used carbon fiber bikes and parts are dangerous.  How about you actually back up your statement?  You're the one making an unsupported statement; before I can tell you why it is wrong I need to know what the support for your argument is.

 

You are getting this sort of response because the last two things I have seen you post on this board were both wildly inaccurate statements regarding bikes. 

 

I will repeat my questions for you:

 

Do you have any experience with riding carbon bikes or having failures on them?

 

Do you have any experience with carbon fiber or composites in general beyond reading about them on the internet?

 

What is the danger in buying carbon bikes or parts and what is your reasoning for that statement? 

 

 

 

M.A.R.K. said:

DUG..

I am not trying to "push the management" on anything. I felt it was a fair question, and is just that, a question. Posed to all(including management), hence my repeated use of the term community. But in typical fashion, nothing but condescension from you. Why not share your knowledge/expertise instead?

I never claimed to be an expert, that is why I was asking questions.

 

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Permalink Reply by Kevin Mulcky on November 17, 2011 at 6:58am

I wouldn't buy used carbon frames, handlebars or seatposts. But then again, I probably wouldn't buy them new in them in the first place.

 

One very tactile advantage I've noticed this fall is that carbon brake levers are much warmer to the touch than metal levers while riding out in the cold.

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Permalink Reply by Unicyclemike on November 17, 2011 at 7:00am

If you are buying a full carbon bike you should know what you are looking at. I would say the same thing if you are looking at a high end aluminum/scandium bike. Unlike steel these materials are more likely to fail when damaged and not simply bend. 

 

If you don't know what to look for you really need to take the frame to a shop and have someone who does look it over. Cracks can be hard to spot and expensive to repair.

 

I would never get a 10 year old carbon bike, let alone 20 unless you plan to put it up on a wall. 

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Permalink Reply by Zoetrope on November 17, 2011 at 8:00am

Well that's rich.  

 

notoriousDUG said:

Mark.... is it just your goal to be a complete troll?

 

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Permalink Reply by Doug Haynes on November 17, 2011 at 10:29am

I just want to know why he thinks it is dangerous; if he feels so strongly it is dangerous he needs to post up and ask about it I think he owes us an explanation of why it is dangerous. 

Brendan said:

Well that's rich.  

 

notoriousDUG said:

Mark.... is it just your goal to be a complete troll?

 

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Permalink Reply by MK on November 17, 2011 at 6:36pm

I think as long as the hypothetical bike is accurately described it should be allowed to be posted. I wouldn't likely buy a carbon bike at all but if I did, like any major purchase, I'd research it first. People still have discretion yeah?

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Permalink Reply by Don P on November 18, 2011 at 3:04pm

Although it appears this thread may be at it's end (M.A.R.K. pulled his response), I thought it may be useful to add my take:

 

I find myself in agreement with DUG regarding this thread.

 

The question implicitly infers that carbon is dangerous, and used carbon FS posts (could, should) need regulation within the community.  I don’t agree, and believe knowledge of carbon fiber will assist anyone in this community who is in the market make an informed, safe choice.

 

Carbon fiber draws more than its share of emotion-filled horror stories on the web, and the many pictures illustrate the full horror of carbon failures.  Also: many consider carbon fiber as an elitist, weight weenie, poser material.  I’m a steel, lugged bike guy, and I don’t think any of that is true.  Look at the total picture and you can find failure in most bike materials.  The spotlight is on carbon fiber because it is new, expensive, and design and manufacturing techniques are still being perfected on an industry-wide basis.

 

Carbon fiber is a pretty new material bike-wise, even though it has been on the scene since the mid-80’s.  It has proven to be a material very sensitive to design and manufacturing techniques.  When done right, the frame and other components can be both rigid and flexible in all the right places, which is ideal for bicycle applications, and weigh less, too.  Corrosion, rust, and fatigue are non-issues.  The carbon fiber property I like best is its ability to absorb road shock.  If you are only looking for bike weight reduction, try dieting first.  Like any new material, there are also some trade-offs – carbon fiber does not respond well to crushing, scoring, deep gouges, or hard knocks.  So, the user has to approach carbon fiber in a way that is different than aluminum or steel.  This means greater care tightening anything carbon fiber and using a metal seatpost when clamping the frame to a workstand.  If you are in an environment where gouging and hard knocks to the frame and components is inevitable, carbon fiber is not for you.  That brake lever you just rotated back into position may have scored your CF handlebar which could cause failure.    Also, in our ‘take marketing to an extreme’ society, there have been carbon fiber components (wheels, spokes) that (in my opinion) are not yet ready for the application, especially for most riders.

 

As for the argument that carbon fiber will not show damage, my response is that you need to know what to look for, and in most cases it can be found.  There are some good resources on the web for this purpose.

 

I do have carbon fiber experience – my 2003 Serotta CSI has a carbon F1 fork, and carbon seatpost – both with zero issues after close to 20K miles on city streets and trails.  In the distant past, I had a lugged carbon fiber (main triangle) Peugeot (which I didn’t like), and I rode a good friend’s Maldone for a couple of months while they were out of the country.  It is an excellent ride, but so is my CSI, and like I said – I’m a steel, lugged bike guy.

 

So, if you are in the market for a CF bike or components, inspection is a must.  As previously stated CF is very sensitive to design and manufacturing techniques.  Off-brand and Chinese constructed CF should be avoided or exceptionally scrutinized due to these reasons.  It also turns out some famous Euro-manufacturers used Chinese CF components on their very expensive designs which have failed in the past (well, at least they designed the paint scheme).

 

Personally, I think there are some excellent deals to be had with used CF bikes and components.  More than a few CF owners have been scared by the horror stories, and want to sell their perfectly good CF stuff at deep discount.  If you know what to look for, their loss is your gain.

 

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Permalink Reply by Anne on November 18, 2011 at 3:39pm

A wonderful post, Don, but please allow me to counter two of your points:

"Carbon fiber is a pretty new material bike-wise, even though it has been on the scene since the mid-80’s." :  In fact, full carbon tubed bikes were manufactured in the mid 1970's, the Exxon (!) Graftek being one. Had the fortune of having a customer bring one in for repair several years ago, it was quite a curiosity and he still rides it. Oddly, just as the use of aluminum in airplanes came over to bikes (late 1920's) carbon fiber use has trickled down from aerospace.

 

A wonderful read on CF from the folks at Calfee: http://www.calfeedesign.com/tech-papers/technical-white-paper/

Secondly, let's all be careful of Chinese-bashing; the 'off' brand may well be the same factory as the name brand. Poor quality in manufacture can be found in Italy as well as Tainjin, in steel as well as CF.

 

Certainly there are some bike models with a history of 'problems' that people like me look at, smirk and say "well, if it hasn't come apart yet it's good!" 

 

Had a friends' steel bike literally pull apart because the BB wasn't welded - it was held together by the paint job. Must have been a Friday 4pm build.

 

Cave canem, 'buyer beware', as Cheap means someone skimped on 'everything' to make a buck, and they are betting on your passion for cycling to be the better of your senses.

 

Don P said:

Although it appears this thread may be at it's end (M.A.R.K. pulled his response), I thought it may be useful to add my take:

 

I find myself in agreement with DUG regarding this thread.

 

The question implicitly infers that carbon is dangerous, and used carbon FS posts (could, should) need regulation within the community.  I don’t agree, and believe knowledge of carbon fiber will assist anyone in this community who is in the market make an informed, safe choice.

 

Carbon fiber draws more than its share of emotion-filled horror stories on the web, and the many pictures illustrate the full horror of carbon failures.  Also: many consider carbon fiber as an elitist, weight weenie, poser material.  I’m a steel, lugged bike guy, and I don’t think any of that is true.  Look at the total picture and you can find failure in most bike materials.  The spotlight is on carbon fiber because it is new, expensive, and design and manufacturing techniques are still being perfected on an industry-wide basis.

 

Carbon fiber is a pretty new material bike-wise, even though it has been on the scene since the mid-80’s.  It has proven to be a material very sensitive to design and manufacturing techniques.  When done right, the frame and other components can be both rigid and flexible in all the right places, which is ideal for bicycle applications, and weigh less, too.  Corrosion, rust, and fatigue are non-issues.  The carbon fiber property I like best is its ability to absorb road shock.  If you are only looking for bike weight reduction, try dieting first.  Like any new material, there are also some trade-offs – carbon fiber does not respond well to crushing, scoring, deep gouges, or hard knocks.  So, the user has to approach carbon fiber in a way that is different than aluminum or steel.  This means greater care tightening anything carbon fiber and using a metal seatpost when clamping the frame to a workstand.  If you are in an environment where gouging and hard knocks to the frame and components is inevitable, carbon fiber is not for you.  That brake lever you just rotated back into position may have scored your CF handlebar which could cause failure.    Also, in our ‘take marketing to an extreme’ society, there have been carbon fiber components (wheels, spokes) that (in my opinion) are not yet ready for the application, especially for most riders.

 

As for the argument that carbon fiber will not show damage, my response is that you need to know what to look for, and in most cases it can be found.  There are some good resources on the web for this purpose.

 

I do have carbon fiber experience – my 2003 Serotta CSI has a carbon F1 fork, and carbon seatpost – both with zero issues after close to 20K miles on city streets and trails.  In the distant past, I had a lugged carbon fiber (main triangle) Peugeot (which I didn’t like), and I rode a good friend’s Maldone for a couple of months while they were out of the country.  It is an excellent ride, but so is my CSI, and like I said – I’m a steel, lugged bike guy.

 

So, if you are in the market for a CF bike or components, inspection is a must.  As previously stated CF is very sensitive to design and manufacturing techniques.  Off-brand and Chinese constructed CF should be avoided or exceptionally scrutinized due to these reasons.  It also turns out some famous Euro-manufacturers used Chinese CF components on their very expensive designs which have failed in the past (well, at least they designed the paint scheme).

 

Personally, I think there are some excellent deals to be had with used CF bikes and components.  More than a few CF owners have been scared by the horror stories, and want to sell their perfectly good CF stuff at deep discount.  If you know what to look for, their loss is your gain.

 

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