A version of this article was originally published in Triathlete Magazine and below taken from http://fitwerx.com/titanium-vs-carbon/
There is a fair amount of misleading information out there about the benefits and disadvantages of different materials. Engineers have been heard to say, “There are not any bad materials, only poor applications.”. This is definitely true with bike design and, when done well, both titanium and carbon fiber are excellent materials to be considering. This being said, each material has benefits and potential drawbacks and who builds it will have more to do with the end results than the material being used.
By keeping the following three things in mind, you will be able to find a material and design that works well for you.
1) Fit – Regardless of material, do not even consider a bike that does not fit you well. It is highly recommended that you be professionally fit first and allow your riding position to determine which bikes match your riding position well. While many bike shops and consumers approach this in reverse and allow a bike model’s geometry to determine what the riding position will be, using the rider’s position to determine the frame is a much more reliable approach to finding a comfortable and efficient riding bike.
Titanium and carbon fabrication are very different and it affects the fit options available in each material. Titanium, and other metals, can be cut and welded to just about any length or dimension needed. Therefore, most titanium frames are available in a wide range of sizes and custom geometry is also readily available with many builders. If it is sized and designed properly, just about anyone should be able to get a properly fit titanium frame.
Carbon fiber frames are built in two primary ways – bladder molded (also called monocoque) or bonded (also called lugged) designs. Many of the most popular designs in triathlon (Cérvelo P3 Carbon, Kestrel Airfoil, Kuota Kalibur, QR Lucero…) are bladder molded as this technique offers almost limitless aero shaping options. However, bladder molding construction has one notable limitation – an expensive mold for each size must be built. For this reason, frame sizes are sometimes limited and these frames will either fit you well or not.
While not being as common with many triathlon specific brands, the other way to fabricate a carbon fiber frame is through bonded construction where tubes and lugs (think tinker toys) are epoxied together. Because each size does not require its own mold, more sizes are easier to offer and custom geometry is possible with some builders. With the notable exception of Guru’s Crono model, which is the first full carbon frame to offer custom geometry options and aero tubing, most lugged frames use round tubing.
2) Ride Quality – While generalisations like, “Carbon damps vibration but feels ‘dead’.” or “Titanium is lively, but not stiff.” are abundant, the reality is that they are also not particularly accurate. The ride quality of the frame is less about the material and more about how the builder used the material in their frame design.
Titanium tubing is available in a huge array of shapes and quality levels. What tubing is used and how determines whether a titanium bike will be stiff or soft, compliant or harsh. The important thing to make sure of is that the tubing and frame design matches your needs well. For example, if you are 120 lbs., over-sized tubes will make for a harsh riding frame, whereas if you are 200 lbs. it can help make the bike stiff enough for you. There are titanium frames available for virtually any size rider and it is a matter of finding the ones that match your ride quality needs best.
Carbon fiber’s biggest promise is that it can offer virtually infinite tuning and shaping options by altering the modulus (density) of the carbon and its lay-up. Depending upon how the designer specifies the frame lay-up and the quality of the carbon fiber, a carbon frame can be made to ride just about any way imaginable. However, because each design is different, like titanium, some frames will ride better for you as an individual than others, so scrutinize the design to make sure it will work well for you.
In both titanium or carbon, some of the better custom builders (Serotta, Parlee and Guru are good examples) offer models that actually match the flex of the frame tubing to your individual needs. This provides a ride quality that is individualized and uncompromised and often does not cost any more than a stock frame built with equivalent tubing and craftsmanship.
3) Ownership Experience/Goals – How long do you want to keep your bike/frame? What is the likelihood the bike will be in a crash? Do you ship or fly with your bike? These are important questions that many riders do not pay enough attention to and one of the places materials and builders can differ the most.
Titanium is an exceptionally hard, durable and corrosion proof material. When built properly, it is a lifetime frame material that puts up with abuse better than any other material. Another option is to consider a mixed material frame. The better mixed titanium/carbon bikes use high grade carbon in places where it can enhance the ride the most, while using titanium where it can enhance durability and sizing options most.
When built properly, carbon fiber can also last a long time. However, one of the challenges with carbon production is consistency in lay-up unit to unit. Carbon construction has little room for error and small inconsistencies in molding and bonding can lead to problems down the road. The more attention to detail and material a builder uses, the less likely such inconsistencies will occur. Research how the frame is built and by whom (many brands do not build their own frames) and explore if there are any known issues before buying it. A good dealer can provide a lot of insight in this regard.
Carbon fiber is also not as durable as metal. Chain mis-shifts, crashes, rubbing during transport and shipping are all more likely to damage carbon fiber than metal and more care must be used with carbon than with titanium. Regardless of material, the lightest frames tend to be built with the thinnest wall structures and often tend to be the most delicate, so choose accordingly and make sure that any frame you are considering will coexist with your training and lifestyle well.
Materials have advanced markedly in recent years and the ride and performance options available are better than ever. If you approach buying your new bike from an individualized standpoint, you will find the material and designs that fit and ride best for you.
Good luck and ride hard!