discussion of Frame Materials!
Steel, Aluminum, Ti or Carbon?
Here is the basic
thesis of this essay: there are three forces that
have recently and profoundly changed the design of
the road-racing bicycle
- The usual search
for competitive advantage on the race course.
- The manufacturer's
search to reduce costs, and the corollary desire
to reduce the number of items manufactured.
The result? Most
people are being sold bicycles that have had their
ride quality seriously compromised in the name of
increased performance that is really illusory. To
put it bluntly, the bikes they are being sold ride
like bloody hell. The pleasure that can be had by
riding a delicious, well-designed, comfortable bike
that is competitive at all but the very highest
levels of racing has been denied to the majority of
the modern road bike riders.
A discerning rider
should look upon lightweight road bikes as basically
falling into two categories.
- All-out racing
bikes (and lower-priced clones that purport to
be the same, but have none of the competitive
advantages and all of the disadvantages of these
bikes) that, while not offering the most
comfortable or pleasurable ride, give the
serious athlete a chance to race without
worrying that his equipment will hold him back.
Many items that claim to be in this category are
marketing tools aimed at the misinformed. But
more about this later.
- Riding bikes. An
intelligently designed bike will offer a
wonderful ride, handle like a dream and only
slightly compromise the all-out need for the
ultimately competitive bike. I believe that
these are the bikes most people should ride.
This all used to be
In 1975, a
professional rider rode a bike made of Columbus, or
Reynolds 531. The usual group was Campagnolo Nuovo
Record, but a mixture of French or even Spanish
components could be used. The rims would be tubulars
like Fiamme strung up with 36 spokes, and have
handmade (cold-treated) tubulars glued on. The bars
were most likely Cinelli, the chain and cogset
Regina. The bike probably weighed about 21.5 pounds.
It was the state of the art. No bike could be made
that was faster, more reliable or significantly
At the same time, no
bike could be had that rode better than a handmade
frame, built by a master out of 531 or Columbus and
assembled with the pro equipment of the day. The
bike was not only competitive at the highest levels
of the sport, it rode comfortably and had excellent
vertical compliance so that it adhered to the road.
The sensual element that gives a bike ride its real
pleasure could find no better tool than the true pro
bike of the '70s.
Bikes have changed.
Those changes require that a thoughtful person
contemplating the purchase of a new bike to use a
different set of criteria than a rider of the '70s
and '80s. It's no longer enough to just want what
the pros ride.
As I stated in my
opening paragraph, there are several forces at work
changing the design of the professional racing bike.
First of all, the most easily noticed is the march
to lighter weight. This has caused the UCI (the
governing body of worldwide bike racing) to require
that bikes weigh at least 6.8 kilograms (15 lbs.).
There is a fear that the technological advance will
obscure the importance of the human effort in a bike
race. The UCI wants to make sure that the emphasis
is on the athlete.
There are two other
forces at work. Manufacturers want to reduce the
number of different items that they manufacture.
Sometimes this ends up being for the better.
Threadless forks are lighter, the stems are stiffer.
The manufacturer gets to make only one fork and cut
it to length. Previously he had to make a different
threaded fork for each size frame. His life is
simpler and the bike is lighter and stiffer.
Compact frames reduce
the number of frame sizes that need to be
manufactured. We make the Corsa Strada (not a
compact frame) in 18 sizes, each with a unique
geometry. This many items, all complex and
differernt, are a manufacturer's nightmare, but a
bike rider's dream.
Fit and weight
distribution on compact frames, however, can be a
problem. If a person is between frame sizes, the
choice between a too-short or too-long stem (and the
same with the seat post) will result in a poor fit
and bad handling. The miniscule weight savings does
not make up for the disadvantages. But, the
manufacturer has saved a bundle. And you'll look
like the pros in the Tour de France who are being
paid to sell this line of baloney.
Another force driving
design is advertising. Marketing costs are huge. In
the sport-driven world of bicycle advertising, these
costs have ballooned. Up until the 1970s, a big
bicycle factory could, on its own, sponsor a
high-end bicycle team. Gone are the days of a
Peugeot team stocked with Tour winning riders like
Thevenet. The last team sponsored primarily by a
bicycle company was TI-Raleigh. And this was
possible because Tubing Investments, the owner of
Raleigh, amortised a lot of the costs of the team
over other branches of the conglomerate. Today, the
bicycle supplier generally plays a much smaller part
in the financing of a pro team, which can cost more
than $8,000,000 a year. With these huge costs, the
pro team has been forced to become a more focused
marketing driven device than in decades past. Every
square inch of the bike and the riders' clothing is
crammed with advertising.
In the past, rim
manufacturers never paid racing teams money to equip
their bikes because the then-used box-section rim is
so anonymous. You never knew which teams were using
what rims. New wheels with deep section rims can
carry obvious and easily recognized advertising, but
this is at a real cost to the rider. The deep rims
ride very harshly. The reduced spoke count wheel
have very high spoke tensions that exacerbate the
The consumer is sold
the wheels because they are light. But, this is a
half-truth. Because the rims have deep sections, the
inertial mass (rotating weight) is greater. The
result is that the bike has less snap and rides more
harshly. To make it worse, tests have shown that a
rim needs to be 40 mm deep to have any real
aerodynamic advantage. The rims with their cross
sections in the 30mm's are not aero, they are only
fancy looking. Before buying one of these wheelsets
that have lots of gee-whiz, consider a nice set of
32 hole, cross-three wheels with box section rims.
Put a pair on your bike and give them a chance.
Borrow a buddy's set if you have any. The weight is
almost the same. But the ride.........
On to the frames.
Bicycle frames and
forks are made of four different materials: steel,
aluminum, titanium, and carbon fiber. There other
materials on the fringe, but they are beyond the
scope of this discussion.
Steel, aluminum and
titanium are metals with an interesting
relationship. Titanium has 1/2 the density of steel
and 1/2 the tensile strength. Aluminum has 1/3 the
density and 1/3 the strength of steel. Now the
obvious conclusion that one can draw from this is
that a frame of aluminum should end up weighing the
same as a steel frame. A given cubic volume of
aluminum weighs 1/3 as much as the same volume of
steel. But because it has 1/3 the strength, one
would need 3 times the material to make a given
It's not that simple.
In building bicycles, made of 9 tubes, there are
problems in drawing the tubes too thin in relation
to their diameter. Given the current state of the
art, a bicycle downtube of steel is roughly 32 mm in
diameter. It can be drawn so that the walls are
about 0.4mm thick. Any thinner and the tube can
buckle easily, and the tube is subject to denting as
downtubes are usually oval for greater resistence to
bending under the normal load of pedaling. The
mechanical characteristics of aluminum are inferior
to steel. It will fail more quickly under repeated
stress. So, the diameters and wall thicknesses must
be increased, but not as much as would be called for
to make up entirely for the reduced tensile strength
of aluminum. With a 42mm diameter, aluminum tubes
can be drawn down to 0.7mm yielding a tube that
weighs 185 grams, compared to 220 grams for a
state-of-the-art steel downtube. Multiplied
throughout the bike's 9 tubes, it is obvious that a
significant weight saving can be achieved using
non-ferrous (non-steel) materials. Intermediate
weight savings can be gained using titanium.
We know more about
steel than any other of the materials used to build
bikes. It is one of the basic building blocks of our
civilization. Even though it has been over 150 years
since Henry Bessemer figured out how to produce
steel commercially and cheaply, new developments
keep coming. In the early 1990s, Columbus announced
the introduction of Nivachrome steel. Previous
steels used to build bikes were chrome-moly alloys
that lost as much as 40% of their strength after
brazing. Nivachrome was the first alloy specifically
developed for building bicycles. In the hands of a
competent builder, Nivachrome loses only 10% of its
strength after building. Also, it is a highly
ductile steel (not brittle like glass) and has a
very high tensile strength. The results? Steel tubes
could be made thinner and lighter.
so much strength was lost in brazing or welding, the
tubing maker had to put a lot of redundant material
in the tubing to allow for the loss of strength. A
normal tube in 1976 was 0.9mm at the butted end and
0.6 in the center. With Nivachrome, that changed to
0.7mm at the butt and 0.4 in the center. This is a
reduction of 1/3 of the mass of the tube with no
loss of strength or durability.
The resulting bikes
made with these modern 0.4mm thick tubes were light
and had a new, beautiful, elastic, delicious sensual
feel that I cannot describe. I can only tell you
that it is there.
The other advantage
of steel is reliability. Modern metallurgy teaches
that if a steel tube is bent and released
repeatedly, it will not break as long as the amount
of this bending remains within what engineers call
the "elastic" range of the metal. When a
steel tube is bent until it permanently deforms, it
is said to have failed. As long as the frame is
never bent beyond it's elastic range, its life will
be very long, indeed.
But let us not
deceive ourselves. The slight weight disadvantage
that comes with a steel frame makes it unusable for
racing at the highest levels. A steel frame can be
made that weighs in the mid to low 3-pound range.
Over a non-compact aluminum frame, this is a penalty
of about one pound. This is just too heavy to chase
Tyler Hamilton up a category-one climb. That is why
the professional peloton uses aluminum or carbon.
But for the rider who does not compete at the elite
level, that one-pound penalty as part of a whole
rider/bike package that approaches 200 pounds (or
may generously exceed it) is insignificant. And for
that pound, the rider gets a bike that can take
advantage of the high-tensile strength and springy
elasticity of modern steel and ride a bike that is
an absolute dream. No bike rides as well as a steel
bike built by a skilled builder. People who disagree
with this conclusion usually have either a
commercial interest in other materials, or have not
ridden modern steel bikes.
Forks. Putting on a
full carbon fork will save almost a pound. This is a
huge weight savings in a single component for a very
modest price. I will save most of my comments for
the carbon discussion below. But, because the
deformation of steel under load is linear, the
springy feel of a steel frame is greatly enhanced by
the lively feel of a steel fork.
of the aluminum frame has been going at the speed of
light. The first modern aluminum frames that showed
up in the mid 1970s by Alan of Italy used the same
diameters that were then used in making steel
frames. The resulting frames were very light, but
they were so soft, I considered them unrideable.
Vitus also made aluminum frames that were very soft
and very light. I could say these were terrible
bikes, but Sean Kelly beat the rest of the world
like gongs with these spongy imitations of real
bikes. There are many roads to the same place. One
man's food is another man's poison.
started tig-welding extra-large diameter alumunum
tubes (Klein and Cannondale come to mind). The
resulting bikes were fantastically stiff, very
light, but hard as nails. I considered them terrible
alternatives to good steel bikes because they had
gone too far the other way. The ride was just too
The engineers never
stopped working on solving the problems aluminum
presented. Columbus came out with Altec and the ride
got better. Easton's offerings made frames that I
finally admitted were tolerable. Columbus' modern
tubes Altec2 and Airplane make fine riding bikes. I
don't put their ride quality in the class of the
good steel bikes. But, if a rider is seeking
competitive light weight and acceptable ride
quality, a non-compact, horizontal top-tube aluminum
bike will serve him well. The earlier problems of
aluminum's tendency to fail after only a short time
has been basically solved. But the lifetime of an
aluminum frame is not and will not be that of a
steel bike. The rider has to accept that in his
search for high-perfomance, compromises must be
made. These are not lifetime bikes. They just
This is the middle
ground. Titanium is not as strong as steel and it is
not as light as aluminum. The result is a frame that
has a better ride than aluminum, but weighs more. It
doesn't ride as well as steel, but it is lighter. It
is very reliable. Titanium frame failures, like
steel frame failures, are very rare. Titanium also
has another advantage. It doesn't rust. Riders in
areas where roads are salted like titanium frames.
They don't have to be painted. If the decals get
wrecked, new ones are easy to apply.
I have good friends
whose judgement I respect who insist that this is
the best material from which to build a frame
because of its middle ground between aluminum and
steel. At this point, it becomes a matter of taste.
I think it was about
a decade ago that Greg Lemond predicted that carbon
fiber bikes were the future. I don't think they have
yet lived up to that promise, even with Lance
Armstrong's six Tour de France wins on carbon.
The first carbon
frames I recall were from Alan and Vitus. The
aluminum tubes that were usually glued into aluminum
lugs were replaced with carbon tubes. Then, the next
big advance came from Kestrel with a monocoque
frame. Lots of riders went wild over them and adored
the ride and lightness. Like all early products, all
of the above frames suffered from growing pains.
Reliability just wasn't there.
If we fast-forward to
today, the advances have been profound. The basic
problem of carbon's reliability has been solved.
Millions of men and women trust carbon for the their
forks, the component on a bike that requires the
greatest level of quality and reliability. A broken
fork can be catastrophic.
Producers of carbon
fiber products have advanced the basic technology of
the raw material. Carbon fiber products are made of
carbon fiber imbedded in an epoxy resin. As the
technology has advanced, engineers have been able to
reduce the amount of resin as well as cabon fiber in
the basic make-up of a carbon item.
This is important not
only for a weight savings, the basic reason people
turn to carbon, but also for road feel.
I have a theory.
When the first carbon
tubes frames from Alan and Vitus showed up, they
were slightly over size. They were still quite soft
as frames go. Then, when the first carbon fiber
forks were introduced, many of them mimicked the
dimensions of steel forks. They were terribly
underdesgined. They were so soft that the front
wheel would vibrate back and forth in an unnerving
shimmy when the front brake was applied. These very
soft, improperly designed items gave carbon a
reputation for softness. If an item were carbon, it
was assumed that it would give a soft, comfortable
ride. It was not the carbon, which is an extremely
stiff material, that was causing the softness, it
was the engineering.
Look at carbon forks
today. They are built to dimensions that are
appropriate to the material. Carbon forks are stiff,
reliable and well-made.
So how does carbon
fiber affect the ride of the bike? Engineers can do
almost anything they want with carbon. It's all in
how the sheets of woven carbon fiber are laid and
epoxied together. There is, however, a great deal of
commonality in how all carbon fiber products are
designed for bicycles. So, we can paint with a broad
brush and make some general rules.
The epoxy in the
carbon fiber matrix damps high-frequency vibrations.
If you have a nice road, it will take out that road
buzz and smooth it out.
However, because the
deformation of carbon under load is not linear, the
worse the jolt or impact, the harsher the feel. It
can make a good road nice, but it will make a bad
road terrible as it bites back when the usual
elastic limit of the carbon is reached.
Some riders find the
deadening of road buzz delightful and pleasant.
Other find that carbon fiber results in a dead feel.
Once again, it's a matter of taste.
I believe that the
feel of the road is a large part of the feedback I
am looking for as I ride my bike. I am not looking
to isolate myself from my cycling environment. I
want to be part of it. For me, then, carbon works
against my cycling goals. I have never ridden a
carbon frame or fork that gives the fine, pleasant,
comfortable ride under the widest set of condition
that steel gives.
technology, this judgment is only for today.
So, what kind of bike
I still hold that a
modern steel bike built with hand-made cross-three
wheels and good tires inflated to no more than 110
psi remains the gold standard. No other bike will
ride as well.
The elite racer
looking for the lightest, fastest bike is best
served with a lighweight aluminum bike. He can get
good feel as well as high performance with aluminum.
If he avoids compact frames, he will get a finer
ride at almost no weight gain. The important, and
now ignored, questions of fit and weight
distribution are better answered with a
hear and read that steel road bikes have
made a "comeback". COMEBACK? We
don’t think that they have really gone
anywhere. Fans of steel bikes have remained
loyal. As recently as 20 years ago, a
professional rider feeding his family with
his pedaling talents rode a steel (cromoly)
bicycle. End of story as far as frame
materials went. Steel was the gold standard.
Since then, many different materials have
come onto the scene…some more successfully
than others. The general consensus remains
to this day that steel (cromoly) frames
deliver the best overall ride. Other
materials might make a frame stiffer,
lighter, more aerodynamic, and in some cases
some materials might make a frame even MORE
compliant and comfortable than steel tubes,
but the idea is still to make them all ride
as close to steel as possible.
a great frame that rides incredibly well
requires the balance of all these
characteristics (comfort, shock dampening,
weight, stability, traction, etc.). These
attributes are all directly related to one
another. Making a frame lighter
automatically changes or "digs
into" one of the other distinguishing
performance features. So all of these
important riding aspects must be considered
carefully and be balanced. It seems that
steel frames keep this balance at a more
favorable ratio than any other frame
number of brands offering a full line of
steel bikes is dwindling. This is great news
for Torelli and the Mondonicos, but a sad
statement of where the bike industry has
gone in the last 20 years.
know many dedicated riders who have been
riding aluminum or carbon for the last few
years and have decided to go back to steel,
purely for the quality of the ride and the
experience that a steel bike delivers.
Frankly, a lot of them want a more
comfortable bike that doesn’t beat them up
in certain riding situations. These are men
and women who have logged many miles on
stiff, tight, robotic frames for years and
they are quite simply tired of the lack of
personality in their rigs. We mention
durability and longevity when speaking of
steel frames. Aluminum and Carbon frames
have an effective "performance
lifespan" that is much shorter than
steel. This means that the quality of the
ride deteriorates over time. It doesn’t
refer to an all-out frame failure. We think
it is fair to say that a good steel frame,
built properly, can last 25 or 30 years if
cared for. Aluminum and carbon frames are
much less predictable, but we think it is
reasonable to say that they won’t have the
lifespan of a fine steel frame.
are the major reasons riders love steel
Overall Ride Quality, Comfort and Shock
Absorption (important in our area with
the quality of our roads)
Bikes Have the BEST Stability
Provides the BEST rear wheel Traction
and Climb like GOATS!
Longevity – 30 Year Bikes!
Construction Options to Suit Rider’s
needs and to make rider FIT the highest
Favorable for CUSTOM Builds
Steel Bikes Heavy?
NO! Our eyes roll everytime we hear
someone say "I don't want steel because
it is HEAVY." Our kneejerk
reaction to this statement is usually "Get
your brainwashed head out of the
corporate/commercial bike companies fluff
and hype catalog!" or "PAH-LEEEEEEEZ"!
Neither approach will endear too many
find it more constructive to take 5 minutes
to educate you on the current state of frame
materials and their weights.
This topic is best left for in store
conversation, but let us type a few words on
the matter. First off, proof is in the
pudding: we've built full bikes with lugged,
steel frames that weigh in UNDER 17 pounds.
And NO, they did not cost $6000. Most
of the steel bikes we build weigh in between
18 and 19 pounds.
aluminum frames are the lightest available.
There are some exceptions, but if you want
to talk about top-shelf, proven, stage style
frames, this remains accurate. Titanium
is light no doubt, but it has lost the label
as the LIGHTEST bike material. Carbon,
in general, is light....but in some specific
cases it is NOT. When you consider
ride quality, you can debate for hours on
weight vs. material. Ask us (in store)
to explain to you how some companies at the
TOP of the food chain have decided that
Titanium and Carbon on their own don't make
for very good bike frames at all. The
combination of these materials is another
story. More on this when you visit us!
seems to be the material that has come
closest to the goal of doing what steel does
but with less weight. 20 years ago,
aluminum was lighter than steel but it was
harsh riding and too stiff. [There is
a great story about an engineer from a BIG
CORPORATE BIKE COMPANY in the pits at the
Tour De France in the early 1980's. A
team competing in THE Tour was riding his
company's newest aluminum frame. When
the riders returned from the stage, they we
assembled under a tent to meet with the
engineer for a feedback session. The
engineer, through an Italian speaking helper
asked "How was the ride on our great
new frame"....the riders muttered to
each other in Italian and their collective
reply came from the one team member that
spoke a few words in broken English, with a
heavy twist of Italian accent..."It's
a-fast, but it's a-too a-hard!"]
As higher quality materials and aluminum
alloys became available, tubing
manufacturers became more and more able to
make aluminum tubes with a thinner wall
thickness which reduced stiffness and even
lowered weight more. BUT, at the same
time, steel tubing benefited from new alloys
and advancements in production and design.
Steel tubing is now much lighter than it had
been. Also, frame parts like lugs, bottom
bracket shells, seat collars, etc. have been
slimmed down by new materials and production
techniques to reduce full frame weight even
further. This lends some proof in our
eyes that steel is still at the forefront of
frame material. If steel is "OLD
SKOOL" or "RETRO" or whatever
you want to call it, contact Columbus,
Reynolds, True Temper or some of the other
steel tubing manufacturers and ask them why
they continue to spend millions of dollars
on R&D for steel tubes!
that what you lose in weight you gain in
many other departments. A light steel
frame is 3 to 3.5 pounds*. A SUPER
light Aluminum frame is 2.5 pounds*.
So we are talking about .5 to 1 pounds net
difference. If your absolute 1st
priority is building as light a bike as
possible, you won't choose steel. If
you want a very light bike that performs and
rides to the highest quality standard, you
will love a steel frame.
WEIGHTS...not catalog weights or tech sheet
carbon, and titanium are fine frame
materials. After all the touting we’ve
done here about steel frames, you still
might very well be better off with another
material. No worries, our friends at Torelli
and Mondonico all know this very well and
all brands offer frames made of these
materials, and of course, all are crafted in
the Italian Style. If you aren’t sure what
is best for you, please consult with us. We
can give you solid advice. We will always
throw the warning flag if we think a
customer is wandering down the wrong path
when buying a bike or making a fit decision.
Ultimately, it is your choice, but we are
here to help you match your desires and
needs with the right product.
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Copyright 2004 Smart Cycles, Inc. Norwalk, CT USA