Carbon fiber has been increasing used in bicycle frames and components in recent years. It’s very lightweight and still reasonably strong. It also allows framemakers, on the high end, to create areas of varying stiffness by altering the direction of the weave. The area where the down tube, seat tube, and chainstays meet the bottom bracket can be make very stiff, for optimal power transfer, and more compliant in other areas to lessen road vibration.  That’s the theory anyway. There is a lot of marketing hype in the cycling world but there’s also a lot of hardcore bike engineering geekery. I find it credible to a degree. I have changed my mind about carbon seatposts, however.

Thomson, maker of fine aluminum seatposts and stems, has this to say about carbon:

Hoop strength refers to a materials ability to resist damage when clamped. Carbon fiber is notoriously weak in this regard. We feel it illogical to use a material that is not made for being clamped around its circumference in a seatpost. Clamping forces can lead to fiber shearing and/or delamination of carbon fiber.

I think this is precisely what happened in my case: I had raised my seatpost a bit recently after developing a bit of knee pain. It’s the place where it was previously clamped that failed yesterday. I’d ridden a few hundred miles after raising the post. No hard impact  was involved – I was cooling down on my way home when this happened. All I did was sit down after a standing climb and crunch.

I’m convinced. I don’t like buying throwaway stuff. I’d rather spend more money up front for parts that will last a long time. So I went ahead and bought a Thomson aluminum post. It’s lightweight, has good reviews from other cyclists, and has a lot of bling factor to boot. I guess I’m lucky I passed on the Jamestown Classic race yesterday. Having your seat fall off could be a bit of a hazard when going 30 mph.