Carbon fiber tubing is just one of the many products Salt Lake City’s Rock West Composites sells. Tubing is used, among other things, to manufacture bike frames. That’s not surprising to cycling enthusiasts who seem to have fallen in love with carbon fiber models. And yet, carbon fiber is nowhere close to supplanting aluminum as the primary material for manufacturing bikes. Why?
Most of us are familiar enough with carbon fiber to understand that it is lighter and stronger than aluminum and steel. We also know that carbon fiber is used quite heavily in the aerospace and maritime sectors. So it seems strange that a material suitable enough for airplane fuselage panels is still struggling to find a place in bike manufacturing.
According to some experts in Tokyo, it all boils down to two things: mechanical properties and scalability. If the composites industry can address both, carbon fiber tubing could someday overtake extruded aluminum as the default material for bike frames.
Carbon Fiber’s Mechanical Limits
Carbon fiber is not a super material impervious to all sorts of damaging forces. It can break. In fact, some of the mechanical limits of carbon fiber can be very problematic for bicycles. Take the fact that it can shatter when exposed to high impact forces.
Shattering is not really much of a problem for airplanes. Carbon fiber fuselage panels are large enough that impact forces can be spread out across the entire surface of the panel to limit damage. Carbon fiber tubing is another matter.
A carbon fiber bike’s frame tubing is subject to impact forces significant enough to shatter it in an instant. There are many stories of that very thing happening while riders are riding.
One advantage of aluminum is that it absorbs impact forces more easily. The same impact that could shatter a carbon fiber frame would merely dent an aluminum frame. As such, aluminum tends to hold up a lot better to even high-impact cycling. If the composites industry hopes to overtake aluminum, it must find a way to address what is truly a critical mechanical limitation.
Scalability and Manufacturing Costs
An even bigger problem for bike manufacturers is scalability. As things now stand, extruded aluminum tubing can be produced far cheaper than carbon fiber tubing. Furthermore, the technologies for manufacturing extruded aluminum are easily scalable in both directions. Tube manufacturers can easily adjust output with very little effect on final cost. The same is not true for carbon fiber.
It takes a lot more effort to create carbon fiber tubing. And in terms of scale, it just isn’t there yet. No one has come up with a process to mass-produce carbon fiber tubing and still keep it in the same cost range as extruded aluminum. No one has come up with a way to easily scale in either direction without impacting cost.
In the end, cost may be the bigger issue for consumers as well. A consumer faced with a $500 aluminum bicycle as compared to a $1,500 carbon fiber model may not have a very difficult choice to make. Manufacturers are having a hard time selling more expensive carbon fiber bikes over aluminum models that perform well enough to keep buyers happy.
Carbon fiber is a great material for building bike frames. Few people argue that point. But aluminum is still the preferred material because it is cheaper to use and demonstrates better mechanical properties in key areas. It’s hard to argue that carbon fiber bike frames will eventually overtake aluminum, but manufacturers have a couple of hurdles to overcome before that happens.