Which one should i go with on a newly purchased 2009 P2? Is the 70 dollar price increase justifiable for the Carbon version that saves me 15 grams?
15 grams in your cockpit will make absolutely no difference, except for maybe 2 seconds on a 40k. If those 2 seconds are separating you from a giant prize purse, then get the carbon. Otherwise, the carbon is a waste of money. Deep down inside, you already know this. Don’t be a victim of marketing and advertisers.
-Doug
Carbon fiber is a waste of money except in two items; frames and wheels. Every other component on your bike will last longer and be more reliable in aluminum.
Chad
Actually, you are better off with carbon in seat posts and aero extensions as these are major shock/bump transferance areas. I went with AluminX’s as opposed to the CBX Pro because of the base bar being aluminum, but still had carbon extensions, so as to save money ($50+). With my seatpost I went with the Carbon Razor as opposed to the Aluminum Razor for the extra $20.
Arggghhh… this is driving me crazy. It seems as if there is a large contingent of people who think that carbon fiber is a “great shock absorber”, and it “improves ride quality”. This is complete nonsense. Carbon fiber is designed to be as stiff as possible, i.e., it is the opposite of a shock absorber. It is designed to transfer force without bending, flexing, etc… Why do you think it is such a popular frame material? If it were a great shock absorber, then all of the force of your pedaling would be lost in the frame. Instead, because it is so stiff, very little energy is spent deforming the frame, and most of your energy is transferred to the rear hub. There is no magical change in the properties of carbon fiber if it is in the shape of a seat post instead of in the shape of a frame. It is still stiff, and it is still a poor shock absorber.
Of course, there are various composites, and some will be softer than others, and you can vary the stiffness by changing the directionality of the fibers, but in general… carbon fiber = poor shock absorber.
Sorry for the semi-flame spray. Its not intended as a personal attack in any way. I’m just trying to help dispel a common misconception.
thanks for the help. I figured that the non-carbon was the way to go, but wanted to make sure i wasn’t missing anything.
Actually, if carbon fiber had no shock absorbing properties, it would in fact become brittle. The fact that carbon fiber is a weave with resin keeps the overall structure stuff and inflexible, but allows for smaller vibrations, etc. to be absorbed. This is why, at a certain point, cold hardened high carbon steel becomes too brittle. One would think that although Titanium & Magnesium are of similar hardness, they would transmit similar energy through, but Magnesium’s structure absorbs more for some chemo-physical reason. That’s why carbon, when it does snap, tends to break in a similar fashion to shale, which is very hard in one direction, but brittle in the other.
Oh, I fully agree with you. Carbon fiber is not 100% brittle. Off the top of my head, I can’t think of anything which has perfect stiffness (insert dirty joke here) and zero flexibility/shock absorption. But the major benefit of carbon fiber is that it is very stiff, and to think of it as a “vibration/shock absorber” is a mistake, in my opinion. There may be some very marginal improvements over aluminum, but if you can feel the difference, then you sir, have a far more sensitive sense of touch than I.
I have the benefit of crappy roads around here, so I get to feel lots of bumps, both small and large. I find a carbon tends be less jarring - you don’t get that “sting” (like when you hit a ball weird with an aluminum bat), I don’t know if you actually move less from the bump. Aluminum basebars are different as they are long and tubular, and flex. A frame is made of triangles which is the strongest shape known to man (hence the use in what is called truss-construction). An aluminum tube does not flex, etc. when compressed in the long direction, however there is flex when compressed across one end of the tube. Carbon has the ability to absorb some degree of kinetic energy when compressed in the long direction, while still maintaining a good portion of typical tube flex. That’s why you see carbon seatposts and forks on aluminum/titanium/steel/magnesium frames - the carbon can absorb energy in the long direction. The carbon frame came from weight, and the bars from available shapes and again the “sting” factor