Titanium and carbon fiber are newer materials used in bicycle construction. Titanium is a pure metal that is then mixed with alloying materials such as aluminum or vanadium to create a durable bike frame material, according to the website the Care Exchange. Carbon fiber bikes are made of carbon fibers embedded in epoxy resin and layered to varying thicknesses for different bicycle parts. Each has its advantages and disadvantages for bicyclists and certain riding conditions.
Titanium flexes well, so it can be a better shock absorber than carbon fiber, and is sometimes used as a shock absorber in high-end bicycles, according to the REI website. Alek Stanek, writing for the Smart Cycles website, says that carbon fiber doesn't deform under load in a linear manner. The harder the impact, the harsher the ride feels. The epoxy in the carbon fiber dampens high-frequency vibrations. Some riders like this feature and others find it a foreign and uncomfortable sensation, according to Smartcycles.com
Carbon fiber bikes are built from epoxied layers of carbon fibers, and as such, they has a much more pronounced "grain" than metals. Well-designed carbon frames provide maximum strength corresponding with the directions of highest stress on the frame. However, carbon is still not a good material for self-supported bicycle touring because of the different types of stresses on a loaded bike, according to deceased bicycle mechanic and bicycling website writer Sheldon Brown. Titanium is durable and maintains its shape well, but if damaged, it can be expensive and difficult to repair.
The heaviness of a particular volume of a material is called its specific gravity. A given metal doesn't vary enough with different alloy elements to cause a significant change in specific gravity. If a bike is labeled as having light titanium, for example, this is a marketing ploy and not an expression of the material's actual weight. Because of construction techniques, such a titanium bike might be lighter, but not because of changes in titanium's weight. A poorly constructed carbon fiber bike could be heavier than a well constructed titanium bike.
Bicycling Magazine writer John Olson says that titanium is an ideal material for making strong and lightweight frames for larger riders. According to Brown, it is the best frame material for touring in developed areas, though its repair difficulty makes it unsuitable for remote tours. Carbon fiber is extremely common in competitive road riding. As of 2010, carbon fiber is appearing in more mountain bikes because manufacturers have developed models that use full suspension and new construction techniques to withstand the multiple stresses of off-road riding. However, because of its grained quality, unusual pressures and impacts can still cause breakage, according to the Care Exchange. As of October 2010, carbon fiber mountain bikes generally cost several thousand dollars, with fewer models in the $1,000 to $2,000 price range compared to road bikes and titanium mountain bikes.
Brown said he believed that concentrating on bike frame material as a measure of quality is focusing your attention in the wrong direction. Tires, saddle, components, suspension and frame geometry can affect the comfort and performance of a bike considerably, whether it is built of titanium or carbon, according to Harris Cyclery.