MAKING THE BEST POSSIBLE BIKE FRAME CHOICE
Durability
A crucial question a consumer should ask about a frameset is, "How long is it going to last?" The answer to this question entails several things about the bike, including,
a. How well it is built
b. The quality of materials used in the construction of the frame
c. How well the frame stands up to the cyclist's ride style and anatomy
d. How well it is maintained
e. How often it is ridden
Most cyclists will not average more than a few thousand miles a year. On the other hand, top competitive cyclist may ride 20,000+ miles a year. The higher your average annual mileage, the shorter the life expectancy of your frameset: that’s a simple maxim. Having said that, some mediums are better than others for longevity.
All things being equal, titanium is probably the most resilient medium out of which to build a frameset. Ti has incredible resilience against corrosion and, in most forms, provides ample flex without being too soft so that stresses on a properly constructed frame will do minimal long-term damage. The downside is that Ti is a very difficult medium with which to work, and if it does get damaged, it is very difficult and costly to repair. Ti also provides more flex than many other media, and, while providing a comfortable and almost “cushy” ride, may not be an optimal medium for high-performance cycling or heavier riders. Butting, oversized tubing and shaping of Ti tubes is one way to maximize stiffness on Ti framesets, but a lot of larger and more powerful riders complain about Ti’s “marshmallow” or “spongy” feel.
Contrary to almost the entire history of competitive cycling, these days steel is rarely used in high-end bike frame production. However, many small and custom manufacturers still use steel as the metal of choice out of respect for the tradition and art of frame making. Steel rides wonderfully as it can be “tuned” for stiffness and ride quality and it is intrinsically compliant. Steel is also extremely durable and provides good resistance to fatigue. Steel’s greatest pitfall, however, is corrosion; for coastal regions or high rust zones, traditional steel alloys should be the last metal of choice. Modern steels, however, which use Niobium instead of Vanadium in the alloying process, are nearly as resistant to corrosion as Ti. The new Niobium steels, like Columbus’ Spirit tube set, can be extruded to very thin tolerances (down to .37 mm!) and as such are very light, rivaling the weight of 7000 series aluminum tube sets. Traditional steel tends to be much heavier than alternative media, which means that the rider must exert more energy to ride a steel frame.
Aluminum alloys, or matrices, currently make up the greatest number of production road and mountain bikes. Aluminum is often chosen for its remarkable stiffness (depending on the grade, or series, of alloy used), its phenomenal reactivity, its ability to convey a “sense of the road” to its rider, and its incredible light weight. For the last 15 years, the majority of race bikes have been made from aluminum. Aluminum can be machined to very thin tolerances and yet maintain relative stiffness. The tradeoff is a lack of strength and increased brittleness when the tube walls become very thin. Higher fatigue tendencies occur in super lightweight aluminums (like Dedaccai’s U2 tubeset), and the longevity of aluminum framesets is somewhat limited (circa 3 to 5 years with moderate usage). Aluminum is also susceptible to corrosion, but is better in high rust areas than steel.
Scandium is a relatively new medium in frame making. Scandium, like its close cousin, aluminum, is used in so-called “metal matrices” which incorporate aluminum, silicon, magnesium, and zinc in various quantities to strengthen the base metal. Like aluminum, scandium comes in several series: 5000, 6000, and 7000 (see chart below). Unlike aluminum, scandium has a ride and “feel” a bit more like steel and, in principle, can be extruded more thinly than pure aluminum tubesets. On the Periodic Chart of elements, aluminum is number 13, whereas scandium is number 21 and this typically translates to greater vibration absorption, stiffness, and improved resistance to fatigue.
Last on the list of frame making media is Carbon. Carbon is currently regarded as “the new steel.” It is malleable so it can be stiff, reactive, springy, dead, or whippy, and can be almost infinitely shaped for maximum torsional and lateral stiffness. It is, of course, 100% resistant to corrosion, but repeated intense exposure to ultra-violent rays can be damaging to the carbon fiber cloth fibers. Carbon also provides unparalleled vibration dampening which translates into reduced fatigue and greater life expectancy. Carbon can be extremely lightweight without being susceptible to cracking or “whippyness.” Carbon is, however, susceptible to abrasions, and if crashed, chipped, or cut, can have its integrity severely diminished with only minimal opportunity for repair. This vulnerability can be ameliorated with Kevlar and Vectran wrapping of the exterior carbon fibers.
Like titanium, steel, and aluminum, there are various grades of carbon fiber. Perhaps even more than other mediums, the grade and quality of carbon used is an essential facet in the quality, durability, and ride-ability of the frame. For bike frame manufacturing, there are high modulus (HM) and intermediate modulus (IM) carbons, 12K, 3K, 1K and unidirectional carbon weaves, and lately there is CNT (carbon nano-technology). Each carbon has its own unique ride characteristics, and where the carbon tubes originate can have a significant impact on frame quality, ride quality, and frame mannerisms. It is important to note that not all carbon is alike. Even if the look of the carbon weave is the same, the quality of the supplier should be questioned to ensure longevity, safety, and proper ride qualities.
NOTE: in the cycling industry, it’s a good estimate that at least 95% of the carbon frames on the market are mass-produced in Taiwan, China, North Africa, Romania, or Mexico. Very few carbon frames are made in the country in which the manufacturer resides. This is no exception even for some of the most recognizable and prestigious names in cycling. To the best of our knowledge, the only reputable carbon frame manufacturers building their products 100% in-house are Cyfac, Time, Serotta, Parlee, Calfee, and Guru. This is not to detract from or discredit other manufacturers who outsource their carbon frames; rather, it is a fact that is frequently obscured from the consumer.
Carbon framesets come in one of three varieties: lugged, monocoque, and miterjoint. Lugs on carbon bikes can be made of carbon, or any other metal matrix; monocoque frames are one-piece molded frames; and jointed bikes have their main tubes connected at angles which are then typically wrapped in more carbon or Kevlar. A frame can actually be a combination of any of these three processes, as well. If the frame comes from a reputable manufacturer, there is no real advantage to having one type of carbon frame over another. In principle, a genuine monocoque frame (which is extremely rare!) should have fewer flex points as there are no points of jointing tubes: the frame is quite literally made in one single mold. Monocoque frames can, in principle, also be lighter than lugged or miter-jointed frames due to their lack of additional joining materials and bonding agents.
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