Aluminum Vs. Carbon frames
By Claire Lunardoni

There is a range of quality in both aluminum and carbon-fiber bicycle frames.
Many of the frame's attributes, including its durability and stiffness under strain,
depend upon the quality of the frame materials and the type of riding for which it is designed.


Weight
Weight is the primary selling point for carbon-fiber frames over other materials.
Carbon frames can be feather-light (as little as 1 kg) without sacrificing stiffness or strength.
Aluminum frames are light, but weigh more than carbon.

Cost
Carbon fiber is the most expensive frame material.
Even inexpensive aluminum frames can be light and durable.


Stiffness
If a frame flexes too much under the stress of pedaling, power is lost into the bike.
While aluminum is a stiffer material than carbon in a laboratory,
a carbon frame's shape and the weave of the fibers can be manipulated
to make it as stiff as aluminum at the points in the frame where it matters most.

Durability
Carbon can be molded to be strongest where it counts, but the strength of the frame depends on quality of the weave.
Carbon frames may have weak spots. Aluminum frames can take more impact than carbon without breaking.

Comfort
Aluminum frames do little to absorb road vibrations, which can lead to numbness and discomfort in the saddle region.
Carbon fiber dampens road vibrations, leading to a smoother and more comfortable ride.