Some of my friends are going back to roadbikes and I don't want to die alone so I'm shopping. I still have a bias against carbon fiber frames but I sniffed out a deal on a 2011 model Cannondale Supersix (new bike, old inventory). I test rode it next to a Cannondale Caad10 which was nice but the Supersix (the carbon one) felt oh so much more responsive.

I'm reading various horror stories of the lifespan and pitfalls of carbon fiber frames.....anyone here (Txchinaman?) have experience with such? I buy a bike and plan on keeping it for years and years. Am I being too paranoid of todays' carbon fiber?

Why do you need CF? Al is better in many, many ways (heck, steel is just as good, if a tad heavier), and cheaper too. Don't fall for the hype.

Otherwise, why not try Ti? I've got a custom MTB and a cyclocross from this guy, the weld quality and alignment are most excellent, and the pricing is very reasonable: http://www.habcycles.com/ He uses a factory in China that he has direct line to.

If you want a bike that lasts for many years get a titanium bike. A titanium bike with a carbon fiber fork could be a very sweet riding machine. Probably about the same price range too.

I had a Litepeed when they first came out back in the early '90s. It was a good bike, but in those days they didn't quite have it right, and it flexed too much in the bottom bracket area. By now they've evolved into some of the best riding machines on the road. I think titanium bicycle technology is mature. Carbon fiber is getting there, but I don't think I'd buy one yet.

Titanium is very resistant to fatigue cracking - far more than steel, and orders of magnitude better than carbon fiber. That's why jet engines and critical components in high performance airplanes, like wing spars, are made from titanium.

this is Portland...I've never kept a bike long enough to see evidence of fatigue...they keep getting stolen. wouldn't think of spending more than fifty bucks on a bike anymore...i see no reason to enrich a tweaker beyond that.

Adastra, it was because of a side-by-side test ride between aluminum and cf. The CF bike felt a lot better than the aluminum.

Aluminum is a lousy material for a bike. Compare to steel and Ti. Aluminum feels dead, no matter how well it is engineered.

Fukshot wrote:Aluminum is a lousy material for a bike. Compare to steel and Ti. Aluminum feels dead, no matter how well it is engineered.

I tend to agree for the most part, but I have aluminum road and mountain bikes and they're great (both made by Klein - have had them for many years). Not all aluminum is created equal. A Klein is head and shoulders better than say, a Cannondale of the same era.

That said, titanium is far stronger, and is far more resistant to cracking.

Fukshot wrote:Aluminum feels dead, no matter how well it is engineered.

Don't know what that means. How can Al feel "dead", and how can other materials feel "alive"?

AdAstra wrote:

Fukshot wrote:Aluminum feels dead, no matter how well it is engineered.

Don't know what that means. How can Al feel "dead", and how can other materials feel "alive"?

The bounce of an undamped flex-and-return in the frame gives a feeling of slight movement that many find more kinesthetically pleasing. Some describe this feeling as "lively" vs "dead". Judge described it as the carbon frame being more "responsive".

Fukshot wrote:
The bounce of an undamped flex-and-return in the frame gives a feeling of slight movement that many find more kinesthetically pleasing. Some describe this feeling as "lively" vs "dead". Judge described it as the carbon frame being more "responsive".

I've never understood these descriptions, but flex is definitely a no-no in Al, and in fact, in all metal bikes, including Ti and steel. Torsional flex (i.e twisting movement perpendicular to the plane of the frame diamond) is indicative of undersized frame tubes in non-suspension bikes. If they are metal, the frame will soon fail in LCF. Flex in the same plane as the frame diamond can only mean the frame is broken, because the geometry will not allow for such since the top tube and the seat stay will be in compression. If a frame flexes enough for the rider to feel them, the frame will not have a long LCF life. So aside from torsional flex, which is undesirable since it absorbs some of the pedaling energy, the biggest thing that makes me a disbeliever in frame flex as "responsiveness", "liveliness", etc, is the fact that there are many components in the bike that flex and distort way before the frame does: seat, tires, wheels, handlebar grips... these things flex orders of magnitude greater than metal frames do. I think if you can differentiate between different metal frames (or even CF), then you must also be able to feel a pea under 20 mattresses and 20 featherbeds...

What riders often describe as different "feeling" of frames is the road vibration they feel that are transmitted through the different components - tires, seat, frame, handlebars. Different frame materials AND different tube sizing will have different characteristics - this plus the other components account for the different "feel", not frame flex.

Ahh-loo-minny-yum

All I know is I don't like riding a bike with an aluminum frame.

I've got two, the Giant Blue Iguana MTB and a Kamra road bike by Nishiki. Both are steel; both are over twenty years old. I got two frames that fit, and I rebuild as needed. The Kamra is a nice riding road bike--- lightweight steel, oval tubes, but I keep clinchers on it because sew-ups are just too much hassle. Only problem is they are almost unknown nowadays. I've got an old Suntour Stem mount group on the Giant--- got rid of the click shift bullshit within a year. It's set up as a cyclocross with cheap assed knobbies. Out here we have goatheads and cactus, as well as other tire shredding bullshit that I can't name. You either have to do Slime and Kevlar inserts or your sport will be "bike pushing." And that's if you stay on the pavement. The old Giant has held up well, and I'm a hell-raiser.

Bikes are just not that hard to work on. I've built my own from about age 9. (Some more successful than others!) Start by buying one with a frame that fits. It's all maintenance from there on out.

Yossarian wrote:All I know is I don't like riding a bike with an aluminum frame.

Bigot!

No CF. I whehearty endorse the custom ti suggestion.

AdAstra for once I disagree with you. There is a world of difference between the way different frame materials feel. There is even a noticeable difference in feel between different types of Al. My old 7005 frame would beat the crap out of me compared to my new(er) 6061. The only thing I will concede is that the 6061 frame has a ti bar but that's not where I feel the beating. I used the same rims, seat and post on both.

AdAstra wrote:

Fukshot wrote:
The bounce of an undamped flex-and-return in the frame gives a feeling of slight movement that many find more kinesthetically pleasing. Some describe this feeling as "lively" vs "dead". Judge described it as the carbon frame being more "responsive".

I've never understood these descriptions, but flex is definitely a no-no in Al, and in fact, in all metal bikes, including Ti and steel. Torsional flex (i.e twisting movement perpendicular to the plane of the frame diamond) is indicative of undersized frame tubes in non-suspension bikes. If they are metal, the frame will soon fail in LCF. Flex in the same plane as the frame diamond can only mean the frame is broken, because the geometry will not allow for such since the top tube and the seat stay will be in compression. If a frame flexes enough for the rider to feel them, the frame will not have a long LCF life. So aside from torsional flex, which is undesirable since it absorbs some of the pedaling energy, the biggest thing that makes me a disbeliever in frame flex as "responsiveness", "liveliness", etc, is the fact that there are many components in the bike that flex and distort way before the frame does: seat, tires, wheels, handlebar grips... these things flex orders of magnitude greater than metal frames do. I think if you can differentiate between different metal frames (or even CF), then you must also be able to feel a pea under 20 mattresses and 20 featherbeds...

What riders often describe as different "feeling" of frames is the road vibration they feel that are transmitted through the different components - tires, seat, frame, handlebars. Different frame materials AND different tube sizing will have different characteristics - this plus the other components account for the different "feel", not frame flex.

Have you ever flown in an airplane and looked out at the wingtip while going through turbulence? There is definitely a lot of flex going on, and it's designed that way.

On a bicycle too much flex is bad, and too stiff is bad. There's a sweet spot that gives a bicycle that "lively" feel that we're talking about. I've had steel frames for years that were like that, and never had a failure. Different alloys, tube thicknesses, diameters, shape, and overall frame design all contribute to a bicycle's feel and performance - by design.

axel wrote: Have you ever flown in an airplane and looked out at the wingtip while going through turbulence? There is definitely a lot of flex going on, and it's designed that way.

The flex in airplane wings is unavoidable, even with the stiffness offered by Al, because of the length of those cantilever structures. If airframers can have a material that is as light and cheap as Al, and does not flex whatsoever, that's what they'll use. There is no advantage in designing flex in airplane wings; in fact, it makes them inefficient in generating lift. What makes it worse is that Al does not have a fatigue limit, which means airframe structures have limited fatigue lives.

axel wrote: On a bicycle too much flex is bad, and too stiff is bad. There's a sweet spot that gives a bicycle that "lively" feel that we're talking about. I've had steel frames for years that were like that, and never had a failure. Different alloys, tube thicknesses, diameters, shape, and overall frame design all contribute to a bicycle's feel and performance - by design.

Again, I suggest to you that the difference in what you feel between different metal frames is not flex, but rather the vibration response of the whole frame. Al tubed frames tend to be light and bigger in diameter than steel frames, and the vibration transmission through the tires may feel stronger, whereas steel tubed frames tend to be smaller diameter and heavier, which damp the vibrations somewhat more. However, both frames will not necessarily exhibit any significant or measurable flex in the vertical plane.

A double blind test, where two frames, one made of Al, another made of steel, with identical geometries, and with tubes that are sized so that the frames weigh the same, and with the same wheels, bars, seats, posts pedals etc, will be an interesting exercise.

Mason wrote:No CF. I whehearty endorse the custom ti suggestion.

AdAstra for once I disagree with you. There is a world of difference between the way different frame materials feel. There is even a noticeable difference in feel between different types of Al. My old 7005 frame would beat the crap out of me compared to my new(er) 6061. The only thing I will concede is that the 6061 frame has a ti bar but that's not where I feel the beating. I used the same rims, seat and post on both.

I agree that different materials feel differently, and that will be because the geometries will not be exactly the same. I'm also saying that what you feel is not because of flex of the frame, but rather the vibration response of the whole frame as a stiff structure. I would bet that your 7005 frame has different sized tubes than your 6061, that the geometries aren't identical, and the different alloys exhibit different vibration characteristics. Your 6061 might very well be transmitting more road vibes than the other, but it won't be because your 7005 flexes more.

Wow! Didn't realize I was starting a popular thread......I've been reading a lot of forums and such online. From what I read it seems the trouble with CF frames starts when you have an accident. The frames are great at functioning when they're being used properly and upright but don't survive spills like other bikes. It's been a while since I dumped a bike but I'm surprisingly clumsy considering what I do for fun.

I suppose I should call some bike mecahnics and talk to them about what they see come through the door?

Thanks everyone for your input so far!

judgepacker wrote:Wow! Didn't realize I was starting a popular thread......I've been reading a lot of forums and such online. From what I read it seems the trouble with CF frames starts when you have an accident. The frames are great at functioning when they're being used properly and upright but don't survive spills like other bikes. It's been a while since I dumped a bike but I'm surprisingly clumsy considering what I do for fun.

I suppose I should call some bike mecahnics and talk to them about what they see come through the door?

Thanks everyone for your input so far!

The problem with CF is that it is very much a directionally strong structure - the fibers are aligned in the direction of loads, and is strong in that direction. CF parts often have multi layers with multi directional fibers for overall strength, but only with loads in the same plane as the part. A CF tube is very strong in axial loading, i.e. loads along its lengths, but it is weak with loads perpendicular to the fiber alignment. If you hit a CF tube on the side, the fibers can break, which then compromises structural integrity. Worse, you may not even know it since the tube may not show any dents.

judgepacker wrote:Some of my friends are going back to roadbikes and I don't want to die alone so I'm shopping. I still have a bias against carbon fiber frames but I sniffed out a deal on a 2011 model Cannondale Supersix (new bike, old inventory). I test rode it next to a Cannondale Caad10 which was nice but the Supersix (the carbon one) felt oh so much more responsive.

I'm reading various horror stories of the lifespan and pitfalls of carbon fiber frames.....anyone here (Txchinaman?) have experience with such? I buy a bike and plan on keeping it for years and years. Am I being too paranoid of todays' carbon fiber?

I have limited personal experience with full CF frame bikes. I've taken a few for test rides, but my main ride these days is a SOMA Smoothie all steel (front fork included) road bike I built up a few years ago. Steel is real!

My other road bike, made by the now defunct Flyte, has an aluminum frame, but with with CF front fork, CF seat post, and CF chain stays and drop outs. I'm not overly concerned about frame life on this bike since I don't put a lot of hard mileage on it, and it's stored indoors away from sun and climate extremes. I can replace the front fork if it ever sustains damage, but I know the entire frame is pretty much toast if the CF parts of the rear triangle ever get dinged hard. The fibers could be damaged badly enough to cause catastrophic failure in the future, but there's no way to tell just by looking.

I also have an old Cannondale road bike I bought new back in the late 80's. All aluminum frame and fork. The bike has tight geometry and is light and responsive, but not much fun to ride on less than perfect road surfaces. The stiff aluminum frame seems to transmit every bump and crack in the pavement up to my body in a harsh manner. Chip seal roads are brutal.

If I was going to get a bicycle (which I'm not) it might have to be a Broakland Pipe Bomb. I drool over their dropouts. Unfortunately, they're selling almost everything they can make and haven't bothered to put anything but arty shots of themselves screwing around on their web site.

I recently returned to bike commuting after a couple years off... somehow, my cro-moly single speed in 48/16 tooth front/rear doesn't feel as easy-riding as i remember it when I was 25...

I suppose I would recommend gears at this point. Also, actual brakes, rather than the hop/lock/skip procedurepopular around Boston.

Other things i wish I had attached to my current ride:
1) airhorn
2) heat-seeking missile

people LOVE texting while driving... often into the bike lane.

I will go against the grain and say go CF, with a caveat. A CF frame is more likely to suffer catastrophic damage in a crash, or in other words, is less likely to be structurally sound after a crash. I have seen CF bikes last several crashes and others are trashed after one. It just depends on the crash. Surface nicks and scratches will not affect the integrity of the frame. Those scratches are only on the clear coat and rarely hit the CF. This is why many CF bikes survive crashes and remain safe for many years. Of course a steel or Ti frame can be bent or damaged beyond repair too.

If you want a frame that will last forever regardless of what you throw at it, go steel or Ti. If you are like most cyclists I know and buy a new bike every 1-10 years, CF is fine. I prefer CF because you really can fine tune the ride quality of the bike. While manufacturers offer a lot of hype about how much of a difference that makes, they are able to do it.

I guess I would say not to rule out CF. Ride a bunch of bikes and see what you like the most. A CF frame will likely outlast you absent a severe crash. Steel, Ti, and aluminum all are great materials and have their own characteristics. While you may not feel real "flex" in the bike, you can feel a difference. Also, tires and wheels make a HUGE difference in ride quality.

BTW, what bikes are you looking at? I probably love bikes more than guns. . .