Just to add another data point about the current prevalence of carbon fiber in many bicycle frames, here's a couple of some quotations from the former bikelist.org "Frame" forum. The remarks are those of Jim Merz whose bicycle bona fides are originally as a custom bicycle frame builder going back almost 40 years and a technical expert who worked at Specialized for many years before retiring.
"...there is nothing wrong with steel bicycle frames or the people who ride them, like them, or make them. I just proposed to the frame builder list here that steel bikes must be considered as a fashion decision. This is not a put down at all. Lots to things from the past have value but are not very commercially viable. Vinyl records, film cameras, mechanical watches, steel bike frames all have their place with a small fanatic following." and this: "Steel has been used for making bike frames for over 100 years. During this period every trick in the book has been used to make lighter, stronger, stiffer (or let's say correctly stiff) frames. But steel has a high density, and one key feature of steel cannot be changed with alloying or heat treating. This is specific stiffness, or stiffness in relation to mass. It turns out that most metals have very similar specific stiffness values. Aluminum is around 1/3 the density but also 1/3 as stiff as steel, titanium is around 1/2 the density of steel, but also around 1/2 the stiffness. There are a few tricks to improve on this situation. So, in the case of steel tubing one tries to remove material to make the structure lighter by reducing wall thickness. Strength can be maintained with very high tensile steel, but the stiffness suffers with the thinner wall. Increasing the tube diameter will improve the stiffness, but because steel is dense the wall thickness gets very thin. Not good for several reasons, hard to make and sensitive to damage. A way around this is to use a less dense metal. Aluminum is a logical choice as it is only 1/3 the density of steel. Not as strong, but one can make the wall thickness much thicker for strength and stiffness and still be lighter than steel structures. Very high performance cost effective frames can be made this way, along with most aircraft. This design (along with titanium frame material) is however still limited by this specific stiffness ratio mentioned above. But we have a new material that is not limited by the specific stiffness values of typical metals. Carbon fiber matrix offers large performance improvement in all kinds of structures. So carbon fiber matrix has potential for maintaining the strength and stiffness required with much less mass than most metals including the three common bike frame materials. However, careful design and fabrication procedures must be followed. The implementation of carbon fiber in aircraft design has progressed to the point that large percentages airframes are carbon fiber. This is not done for marketing reasons, but because it saves weight and improves service life. Correctly designed bicycle frames made using carbon fiber can show the same benefits. Until some new material comes along it is the first choice for bicycle frames." I've personally never ridden any bicycle, nor have I owned one, that wasn't a steel frame bicycle. I don't, however, think there is any point in criticizing carbon fiber as some inferior material for a bike's frame or components. I also don't give any credence to the idea that carbon fiber is a material that is inherently dangerous or poorly suited to for bicycles. This is, in my opinion, one of those "can't we all just get along" areas. I'm quite happy with my steel frame bicycles. If someone else loves their carbon fiber bike, that's fine with me. Jim Cloud Tucson, AZ On May 9, 5:11 am, Steve Palincsar <palin...@his.com> wrote: > On Sun, 2011-05-08 at 16:26 -0700, RJ wrote: > > I have known two people locally who had carbon forks break and they > > suffered quite a lot of damage. One is a bikeshop owner riding a > > madone, the other was a racer whose carbon spoked wheels came apart in > > a turn. It can happen with any material, but to say that it doesn't > > happen with carbon, which is what I am getting from your post, is > > ludicrous. > > I am not a fan or defender of carbon. > > What I am saying is to single out carbon as though it was especially > dangerous, above and beyond all other materials, is ludicrous, and if > you go by what I see on the forums and message boards, has gone a long > way towards destroying Grant's credibility. > > If it was as uniquely and urgently dangerous as he makes out, you'd > think that in a 39 year long career of being actively involved in > bicycle clubs and club riding, you'd think I'd have heard of at least > one local instance - but no. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bunch@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
