The evolution of various road bike frame materials
Ask a gaggle of roadies what frame material they think is best, and you’ll receive a variety of impassioned answers; some correct, some confused, and some wrong and based upon old wives’ tales. Many riders are polarized in their opinions due to dogma (not the Pinarello, necessarily), preconceived notions, loyalty to a brand or preferred raw material, or “something they read somewhere.”
There have been a few rare frame materials that never caught on, either because of difficulty in manufacturing, stiffness issues, brittleness, cost, durability, or inherent ridiculousness, and we won’t be concerned with those here. Scandium, for example, was an alloy that was mostly aluminum and used primarily by Easton. It’s pretty much antiquated. The obtuse reference to dogma in the opening paragraph mostly represents Pinarello’s daring journey into magnesium-alloy frames, most notable of which was the spectacular Dogma. I won’t deal in rumors or gossip about Scandium or magnesium frames, but they’re pretty much gone from the market. Even the upscale Pinarello Dogma is now carbon.
Other than some really goofy frame materials like bamboo, wood, or cardboard (yes, they all exist), the well-established road bike materials up to this point are steel, titanium, aluminum, and carbon fiber. The first three of those materials are actually alloys, much like cymbals. Quality cymbals, thought to be made of copper, are actually copper-based; bell bronze, malleable bronze, brass, and nickel-silver.
The various frame materials and the implementation of the frame design all have ranges of characteristics including weight, rigidity, strength, workability, cost, etc. I just mentally categorized the new bike frames I’ve bought since 1980, and I’ve owned four steel frames, five titanium frames, four aluminum frames, and five carbon frames. The remainder of this article will look at the advantages and disadvantages of these four frame materials.
Steel fanatics always dutifully repeat the annoying cliché “Steel is Real!” Up until the mid and late ‘80s, it was the universal material of choice. Steel is a great material in that it’s not that expensive, it’s easy to work with, it’s relatively easy to repair, and it has a lively, responsive ride with good stiffness and comfort.
One potential drawback of steel is added weight. A steel frame can weigh two or three pounds more than more modern materials, and attempts to build a steel frame that’s much lighter often results in a frame as pliable as a piece of pasta al dente. In fairness, though, we can probably each lose ten pounds of body weight, and that makes three pounds of bike weight a moot point. Another problem is corrosion and rust. An internally-routed brake cable through the top tube of my 1981 Gios Torino leached sweat inside the frame and rusted the top tube out from the inside. After having a frame builder replace the top tube, it’s still a serviceable bike. Steel frames that are well maintained can have a life of over 100,000 miles, and the frames can actually be fixed.
This material changed cycling and racing in the Greg LeMond era. In the 1992 season, LeMond rode Litespeed titanium frames, painted so sponsors wouldn’t go apoplectic. The other prominent ti builder back then was Merlin. Throughout much of the ‘90s I trained and raced on three Merlins, and I managed to break two of the lightweight frames, one of which was successfully repaired. In the early and mid-‘00s, I used Airborne titanium bikes; road and time trial.
Titanium feels a lot like steel, only a bit more damped, or as some people say, “dead.” Very light ti bikes are soft and flexy, and despite being comfortable, they can feel flimsy and very scary on fast descents. In small numerical gears on hard, out-of-the-saddle steep climbs, the lighter titanium frames would wag their tail; bending at the bottom bracket, seat stays, and chainstays. You could get them to deflect almost a quarter inch.
Flex is the biggest problem with some titanium bikes, especially the earlier ones, and that flex seemed to lead to metal fatigue and cracks. That said, newer ti bikes are light, stiffer, and reliable. Moots seems to be a current premium titanium frame builder.
Despite the flex of early French Vitus aluminum frames, Sean Kelly raced them successfully, including some impressive sprint victories. (Between his scrunched-up bike position and that noodle of a frame, I am surprised he ever won a race.) Vitus had developed stiffer bonded aluminum frames by 1986.
The main proponent of aluminum frames in the ‘80s was Cannondale. They solved the problem of previous ‘70s aluminum frames that were very flimsy. Cannondale went overboard trying to build light, stiff aluminum bikes, and the early ones had a teeth-chattering, unforgiving, rigid ride. They were known mostly as criterium bikes because of their responsive handling, and because no one really wanted to ride one farther than 30 miles. Like Vitus, Cannondale finally got the hang of it and built some excellent, reasonably-priced aluminum frames and bikes.
Aluminum frames were always fairly economical, and today a lot of low-end bikes use aluminum frames. For a number of years, frame builders dealt with the overly-stiff non-bonded aluminum frames by incorporating carbon seat stays and/or carbon chainstays along with a more comfy carbon fork. Most aluminum frames were considered throw-aways after maybe 10,000 miles because many would become structurally compromised, but newer aluminum frames seem to have a much longer lifespan. Adding carbon parts to aluminum frames signaled what was to come…the total dominance and proliferation of carbon frames.
Early carbon frames; like early aluminum and early titanium; had a few serious problems. The early Look carbon frames consisted of carbon tubes bonded together; glued, actually. The ride was sloppy and soft, and even worse, the frames would fail at the bonded lugs. I watched a friend’s Look KG86 literally come apart during a fast group ride, sending him careening off the country road and into an active electric cattle fence. (If you knew this guy, you would have laughed like I did, despite his blood-curdling screams. He wasn’t hurt.) Look eventually figured it out and went with one-piece lugless frames, as did virtually everyone else making carbon frames.
One company that really sorted out carbon and built stunningly beautiful frames in the late ‘80s was Kestrel. I rode a white Kestrel 4000 for a few years, and it was stiff, yet *somewhat* compliant. Other than its internal downtube bladder causing it to creak like an old wooden rocking chair, I could tell that carbon had arrived.
While early carbon frames were costly, most of us ride carbon bikes now, even in moderate price ranges. Carbon has emerged as the near-perfect frame material; very light, stiff, and it can be reinforced in high-stress areas such as the bottom bracket. A carbon frame can also be repaired if damaged, which is something I just found out from a local bike maven.
Most carbon frames are made to be laterally rigid yet somewhat vertically compliant. This makes for great climbing and sprinting without frame deflection, but still with a supple ride. Shameless plug, but out of all the nice bikes I’ve owned, my two nearly-identical carbon Specialized S-Works Tarmacs are the best frames I’ve ever had.
I won’t ever try to talk anyone out of steel, titanium, or aluminum, but road bike evolution has taken us to the golden age of carbon. Maybe next year, Unobtanium will be all the rage…
Written by Paul Scarpelli