The history and development of the Carbon Fiber bicycle…


PRESTON SANDUSKY: Thanks Pia. So like he said my name’s
Preston Sandusky from Kestrel Bikes. And also I have John St.
Denis also known as JD, with me here. I have quite a few slides, so
I’m actually going to try to go through them pretty
quickly. But my background, currently I’m
the product and managing director at Kestrel. I started out as an engineering
manager. And I actually was President
for awhile there before we switched some ownership
around. So my basic background is
mechanical engineer, US Air Force, aerospace, carbon
fiber stuff. We’re really happy to have the
opportunity to come here today, because Kestrel’s a
Northern California company. And Kestrel made the first all
carbon fiber bike in the world on a production for
sale basis. And the technology and the
engineering to do that came out of the bay area
and the Sacramento area aerospace industry. Back before companies like this
were so prevalent here aerospace was really
huge down here. And a lot of that early
technology spun out of that. So let me get started. Like I said, I’m going to go
through some of these pretty fast. I just want to give
a brief history of when Kestrel started. We already talked about it. And then we’ll talk a little
bit about the materials capabilities and why we use
carbon fiber and then walk you through the basic steps of the
design and development cycle on one of our products,
or a couple of our products, actually. So like we’ve already said,
Kestrel started in 1986 down in Santa Cruz. And what happened is the guys
who had started Trek bicycles about 10, 12 years prior to
that got together with aerospace carbon guys and
decided to make a full carbon fiber bike. Prior to that there were bikes,
bike frames, made with carbon tubes, typically glued
to aluminum legs, even steel legs early on. But at the time that Kestrel
came out, carbon bike was round carbon tubes bonded or
glued to aluminum legs. So it was very much metal
bicycle technology with just the tubes replaced by carbon. So the first Kestrel was
called the Model 4000. Here it is here. I keep looking at the screen,
but it’s actually in front of my face. And this bike revolutionized
cycling in a lot of ways, actually. The obvious thing is it was the
first full carbon fiber composite molded
bicycle frame. But it also had things, like
it was the first production frame with aerodynamic tubing,
and I’ll talk a little bit more about that when
we get into it. But the beauty of carbon fiber
is its moldability. And you can shape it
however you want. We try to shape in ways that
make sense, but it’s infinite what you can do with carbon
in a molded shape. Once the first road bike came
out we turned our attention to mountain bikes and
triathlon bikes. In 1988 we came out with a full suspension bike prototype. And many people regard it as
the bike that helped kick start the full suspension craze
that is now commonplace. More people ride suspension
bikes than the non suspension now. This is it, here, the
Nitro show bike. It was actually a
collaboration. For those of you who know some
of the bike history or some of the bike names, it was a
collaboration with Kieth Bontrager from Bontrager Cycles,
Paul Turner, who ended up starting Rock Shox, which,
of course, in ’88, ’89 was pioneering the suspension
fork for mountain bikes. And of course, Kestrel with
the carbon fiber side. We didn’t end up making
this bike. We ended up making what we
call a hard tail version, which is actually a very similar
design but without the rear suspension. Because the things like the
breaks and the shocks didn’t actually exist in the
market at the time. This bike was pegged at
about $6,000 in 1998 for a mountain bike. Later on some of the other
things we brought in that we pioneered to the bike market,
the EMS fork, or the carbon fiber road bike fork, was a huge
thing, came out in 1989. And we also made the first all
carbon triathlon bike. So triathlon is a sport that’s
pretty big these days and really growing fast, and
at that time was really in its infancy. I think we were maybe the
second company to make a trigeometry specific
production bike. And the first one to apply
carbon and aerodynamic tubing to a triathlon or time trial
bike for production. We also came out this
bike in about 1992. This is a 500 SEI. I think the photo is of the 500
EMS. The 500 SEI was its predecessor. And as you can see, it
has no seat tube. And this was a really good
example of what carbon fiber can do, not just for bicycles
but in any structural design. Because there’s no way you’re
going to take steel or aluminum or titanium metal
bicycle frame material and have any kind of efficient
structure by removing a tube like that. And what this bike did, this is
actually a road bike but it was used by a lot of triathletes
as well, as you can see by the set
up in this photo. But what it really opened the
door for was some aerodynamic freedom with our triathlon
bike designs. And you’ll see some more
of that when I get to the design process. This is a lot of words here,
but basically the materials that we use to make frames come
straight out of military and aerospace industries. It’s called carbon
fiber prepreg. And prepreg means that the
fibers are typically aligned along an axis and then coated
or treated with a matrix material like epoxy resin. So prepreg means preimpregnated,
with, in our case, the epoxy resin. Literally we were specing,
taking engineering materials specs right out of aerospace
and applying them to these bikes. In fact, probably the most
important thing that Kestrel pioneered back in the day
was the marriage of real engineering to the
bicycle industry. Prior to that, nothing against
those engineers, but actually a lot of the bike companies had
engineering departments that didn’t have engineers,
because it’s mostly just drawing tubes and mitering
drawings to see what the tube lengths are and how they
come together to be braised or welded. So this was a very engineering
intense project. And I can tell you that joining
Kestrel October ’87 and going from the Air Force
composites office in the aerospace side and then watching
them lay out the whole bicycle frame in one piece
with this material, it’s the kind of thing where a
trained aerospace engineer would just initially just
say, you can’t do that. It doesn’t work that. Bicycle guys are pretty
inventive guys. You’re talking about people
like the Wright brothers. So they’re people that tend to
have some ideas or some dreams and go after it. And not worry about what
other people say can or can’t be done. And I’m sure you folks
here are familiar with that as well. So why carbon fiber? The best thing about carbon
fiber and a bike frame is the stiffness to weight ratio. Bicycle frames are what we
call stiffness critical structures. As many of you know, you get on
a bike and you don’t want it to be flopping and
flexing around. You want it to be stiff. But it’s a two dimensional
structure. The rear end is a little
bit triangulated in the third dimension. That main frame and that main
power transfer is done in a two dimensional plane. So stiffness becomes really the
issue in a bike frame and a lot of bike components. Strength is too, but with metals
you sometimes have the condition where you have to
design something around the strength of the material rather
than the stiffness. With carbon, because the
stiffness is so high, usually once you have the stiffness
under control the strength almost comes along with
it, with the design. We do have to beef up areas for
impact or certain really high stressed areas in
terms of strength or structural testing. But stiffness is the key, and
carbon fiber composites far outweigh metals. And I have a little
chart on that. So here’s the stiffness
comparison. Specific stiffness, I
didn’t really ask. How many of you folks are
engineers or material people? Specific stiffness means
stiffness to weight. And you can see, I
don’t really have a pointer, I think. So you can see here, down here
are the little blue bars. These are these are the typical
frame building metals, steel, aluminum, titanium. Those are the metals that
were being used when Kestrel came out. And they’re still the metals
that are being used in frames today. Maybe not so much as it used
to be, because carbon is probably the dominant high
performance material in bike frames now. But as you can see, those metals
have actually different stiffness properties
and capabilities. But when you factor in the
density of the metals, their stiffness to weight comes
out very much the same as each other. And also a stiffness, it’s
pretty much regardless of the alloy of the metal. Strength varies more with the
alloys, but stiffness to weight is pretty
much the same. And then you can see, on the far
side, the type of carbon materials that we use. I don’t know if I can be here
without being in the way or off the camera. This is the 700K material or
our, quote unquote, “standard material.” And then the 800K
here is our higher modulus material, or what we use
on our SL frames. I don’t know if you guys can
quite read the numbers, but you can tell from the graph that
the specific stiffness of carbon fiber that we use in the
frames is about five to seven times the stiffness
to weight of the metal frame material. So from a pure engineering
standpoint, if you don’t have a background in the traditional
frame materials and you just look at materials
available, it’s just really obvious to use that carbon fiber
composite materials are the way to go. The little red bars next to
the carbon is actually the carbon epoxy. You can’t build a bike just with
carbon, the epoxy has to hold it together. So when you factor in about 35%
or 40% epoxy, you still have a stiffness to weight ratio
of about three to four times what the metals have. And
actually more than that with some of the newer fibers. Strength to weight’s
the same thing. There’s a little more variance
in the metal materials, depending on the alloys,
but they’re heavy. Carbon fiber epoxy, again as
you can see, it has even higher strength to weight than
stiffness to weight. And that’s why I said if you
make the frame stiff enough the strength is almost always
already there for you. So again, the fibers themselves
that we use, 11, 12, 13 times the strength to
weight, or specific strength, of metal materials. And then the carbon epoxy blend
still going to be six, seven, eight times the
strength to weight. It’s an engineer’s dream. A couple other things that
weren’t on the slide. The main point there, I think
is the big one, that carbon fiber epoxy composites are
fiber reinforced plastic. So the epoxy matrix is
surrounding all those fibers, and it’s plastic, basically. So the shock damping
capabilities of a carbon composite material is 10 to 15
times the shock damping of these traditional
frame metals. So imagine if you had a steel
bell, an aluminum bell, and a titanium bell. They would all ring. You’d hear them, they
would ring. You make a carbon epoxy bell
and it’s like hitting a plastic bell, so it
just doesn’t ring. What that allows us to do is
separate the ride quality and the damping of the frame or
the structure from the stiffness and the strength and
the performance side of it. So let’s say you make
a titanium frame. You want it to be reasonably
light and you want it to be comfortable. Well, if you make it very stiff
it won’t necessarily be so comfortable. If you make it comfortable,
you’re getting the comfort out of flex. Flex is bad in a
bicycle frame. So there’s that balance
with metals. You try to balance it out, and
I defy anybody to make a non suspended frame out of metals
that is as stiff as a carbon frame and still has the kind of
comfort you’re looking for. So with carbon fiber you make
that structure, you say, I want it this stiff. It has to to pass these
strength tests. Blend or vary the fibers in the
design according to weight you’re looking to get, and the
shock damping is separate from those properties. So all of a sudden you have a
super stiff bike like these up here, the little
one over there. Very stiff, very, very
efficient, and yet really smooth frames. Now, if you go up against a
curb or something, it’s a stiff frame, you’re
going to feel it. But that rough road buzz and
smaller potholes and cracks and things in the road, it
just gets rid of those. You don’t get that bite through
the handlebars and that ringing in the frame. So a couple general features, or
general design approach in pretty much all of our frames
and products, using carbon. And by the way, we only
make carbon products. The first one is modular
monicot construction. These are the solid models for
the various sizes of that frame, the Talon frame
down at the end. But way back when we used to try
to mold these frames all out of one piece, and
it was great. It worked great. It was very complex, very
expensive, and very, very much less repeatable. About 10 years ago or so we’ve
gone to this modular monicot construction. And what that is taking all
the best out of the carbon fiber design, but breaking it
up into not a lot of pieces, but just a couple
main structures. For instance, the
main frame here. So that’s a solid model
that the mold or the tooling is made from. But it shows that the
whole mainframe is molded in one piece. And then after the talk you
folks can get a better look at the bikes up here and you can
actually see where, say the seats stay in the assembly and
the rear is one piece, and then the chains in
the assembly and the rear is one piece. And then they’re all put in a
bonding fixture and locked permanently together. The other thing that’s a really
big part of our design work, and I think that carbon
leaves you wide open to opportunity, is in optimizing
the tube shapes and the junction design. Somewhat doable in metals,
but difficult. Usually there’s round tubes
or near round tubes. But in carbon, if you look at
some of these designs, you’ll see that from one end of the
tube to another can be a completely different section. It’s all designed around the
load conditions and the structural requirements at any
given point in the frame. Also we can bring in
aerodynamics, to see the aerodynamic tube shape there
in the down tube. Maybe the down tube might
flare out to the bottom bracket to make it
stiff there. Some of the sections go from
flat at the front, at the head tube, the top tube on
the top of the bike. Up near the front, at the head
tube, they might be more of a horizontal section, and
gradually morph to a vertical section. So it’s infinite. Anything you can put in the
computer, which is pretty much anything these days. Didn’t used to be. Pretty much anything you put
in there you can make with carbon fiber. The site specific structural
design and fiber layup, again, it’s becoming the norm
now in a bike frame with carbon fiber. Whereas with metals you might be
able to use a thicker tube or a bigger diameter tube
as you went up in size. But typically it was really
hard to have a consistent performance and consistent
structural properties throughout a size
range of bikes. But now we literally size
every tube of the bike proportional to the
size of the frame. And sometimes more than that. Sometimes even wheel sizes and
things are proportional to the size of the frame. But by sizing that tube it
might look the same. The general shape and design
might be the same, but it’s just a little bit smaller or a
little bit bigger for each frame size. And that means the 100 pound
rider on the smallest frame has the same kind of ride
quality and feel and response as the 250 pound rider
on the largest frame. And that’s the goal there. In addition to that, the carbon
fiber layup itself, we can put more or less layers of
carbon fiber in a given tube or tube junction to make the
frame lighter or add material to make it stiffer. So we can tune it. The bonding design and
techniques, since Kestrel started we’ve used aerospace
grade structural adhesives. This is not so much a point
for this audience. Some of our competitors use
cheaper spec materials, like a one part epoxy. We use a two party epoxy. They actually have to
squirt it out in production and mix it up. But that’s what gets
the best results. It has the higher strength,
the higher sheer strength. And it gives you the better
quality and product. The other thing that all our
frames are going to have, the ride tune stays and our
EMS sport technology. So like I said, we introduced
the carbon fork to the world in 1989. And what we do now is every
model of bike has its own specific design fork. So if you look at the image here
you can see the mainframe in blue and then you see the
rear stays in the silver or gray, as well as the forks. So what we’re able to do these
days is to match the performance and match the
quality and design of the front end to the rear end. So you get a very balanced
ride and a very balanced feeling. A repeatable performance
our of the frame. No compromise geometry, that’s
just something we do because even though we’re carbon fiber
engineer guys we’re a bicycle company first. And so what we
try to do is not cut corners to make one size fits
all frames. It seems a silly thing
to do in carbon, because carbon’s so light. There’s no reason to make a tube
a little bit shorter to make a frame a little
bit lighter. Get the geometry right, fit
the rider correctly, and design to that just as you would
to weight or stiffness. Let me grab a little sip here. This picture is reminding me of
some basics of what we do. And now we have a couple frames
that’ll show you some images, some examples
of the actual design process we go through. One of them’s the SRT
700, which is our brand new road bike. We have a couple of them up here
you can check out after. And then the other one is our
real tri race specific bike, it’s called the Airfoil Pro. It’s very specific to
triathlon racing. It’s not legal, actually,
for any road racing or time trial use. But it’s a very fast bike. So I think I’ve covered
most of these points. We do all the design, all the
engineering is done in our Santa Cruz offices. The frames are made overseas,
like just about everybody is these days. We used to have a factory
in Santa Cruz. And like most bike companies
that go overseas to get carbon, we actually have
experience and the engineers who have set up factories in
not only in the US, but in other countries as well. So we can go to those factories
and we know how to layup bikes. And we know how to do the
finishing work and all. In fact, from the president of
our company, who has set up carbon bike manufacturing
factories around the world, and on down. I talked a little bit, but just
to reinforce that the carbon is infinitely tunable. So it comes in very thin sheets,
and what we do, I don’t think I really showed this
because I don’t really have the manufacturing so much
as the design stages here. So what you can do with the
carbon, it’s usually what we call unidirectional carbon. So the carbon’s all going in one
direction on the sheet and then the sheets are cut to the
different angles that we need and we use different thickness
of sheets that we need. And then we stack those
the sheets. So say we need six layers in
this big tube or we need five layers in this smaller tube,
or what have you. The different number of layers,
the angles, the thickness, is along the tube
or at the junctions. All that’s tailored to the
particular design. Everything we do now is
3D, solid model, CAD. It didn’t used to be. When I started at Kestrel I
was drawing center line drawings by hand and working
with industrial designers and actually drawing it on paper. And then the interesting thing,
when we got into real 3D modeling, is that
the software is really capable now. But about 10, 12 years ago when
we first starting to do it seriously, even say we use
Pro Engineer software. And we had designs that those
guys couldn’t model. So we actually had to have
customized software made to be able to model the crazy compound
curves and shapes that we were doing. But this is how the design
cycle starts out. We actually work with some very
good industrial design firms, usually local to
the Santa Cruz area. And we give them some
definitions on what we’re looking for in a bike and start
bouncing ideas around and getting some
sketches going. This is the Airfoil Pro tri
bike that I showed you. Once that basic concept is done
then we start getting into the details. OK, how is the cable routing
going to work? What’s the seat binder
going to look like? So they’ll get into these
multiple iterations of these types of sketches. This one looks to be pretty far
along in the process in terms of the hand sketches. And sometimes, by the way, they
use computers for their conceptual stuff or
sketch type stuff. That’s a little cable port that
came out of, probably, a dozen concepts. It’s the one we zeroed in
on the RT 700 bike. Once we have the concepts done
we’ll start doing the solid model CAD drawings. I like this shot because,
again, this is the Airfoil Pro. But what it shows is the solid
part there is the main frame. So the main frame design
was pretty much done at that stage. And so now they’re building the
rear end onto the bike. They’re laying out all the
clearances and trying to put in the hard points, like the
rear drop outs where the wheel bolts in and where the
brake bolts in. And then a little further
on, same frame. This is a cool shot because
you can actually see those green and gray lines that are
going down the main big tube on the screen, the down
tube, is actually some of the cable routing. So they’re able to put in the
anticipated thickness of the carbon fiber wall and simulate
the cable routing through the frame, make sure there’s
no interferences. Little hard to tell, but you
can see some of the little metal pieces that are bolted or
riveted onto the frame that guide the cables and things. So we’re actually able to put
those into the CAD model and make sure everything’s good,
functions properly, before we go to CNC machine, a very
expensive mold. And by the way, all this stuff
we do, if we make five or six sizes of a frame, it has to
be done for all the sizes. Here you can see, this
is the RT 700 model. And obviously this is a
fairly finished model. But you can see some of those
concept sketch pieces, like the little gold cable guides,
where they’re actually fitting them into place and designing
the frame to be molded to accept them. Other one, that under
the bottom bracket cable guide piece. This is a little injection
molded thermoplastic piece. And it went from that, I think,
three piece concept sketch down to this. So basically there’s
little ports. I don’t know if you can
see my point here. So this port area is actually
a hole through the frame and the cables come out. And then you can route them
through the plastic piece. Lost my marker again. There it is. And then it goes into these
holes here to go up to front derailer and rear derailer. I’m not sure what
this shot’s for. I just think it looked
really cool so I could put it in there. It remind me of a Terminator
Two liquid man. But it was a rear drop
route of the RT 700. This is a problem. We have a little power problem
up here, I guess. I should have turned my
lighting down more. So then, actually, a big part
of it is checking all the clearances. I think they’re IGES files from
Shimano, or whoever, and actually put the components in
and check all the fit and clearances. I’m going to run out of power. It might be pretty
done anyway. And then using the CAD model we
can do some finite element analysis depending on what
the frame is and what the needs are. This bike doesn’t have a seat
tube, so it’s kind of nice to put some loads into it. You can do the whole frame
or you can do sections. Sections are usually the
better way to go. | we can do with the CAD models
before we commit to tens or hundreds of thousands
of dollars worth of machine metal molds is, this
is actually a CNC machined piece of foam. Actually several
pieces of foam. So they actually machined a
frame out of solid foam, assembled it together,
we check it out. Typically we change it. We did change some design
details on this. There you go, thanks. Excellent. I can turn my lighting
up here a little. That used to be really expensive
stuff to do. And the prices on getting that
stuff is going down like mad these days. And in fact this piece is
actually done in house by the industrial design firm
we work with. And then, boom, you
have prototype. Once you check everything out
and make the mold we go to prototyping phase. And this is probably the
first or second main frame of the RT 700. My cursor shows up, you can
see the little port here. That’s actually the little metal
port and that’s actually a stereolithography prototype
part as well. I don’t know why my
cursor disappears. Back here you can see
these little tabs sticking out in the back. That’s where the stays in the
rear is going to bond on. JD, how’s the time? OK, thanks. Another little prototype. Not the prettiest picture,
but this is raw, right out of the mold. There it is. So this is an SLA part
stereolithography. Part, I don’t know if you are
familiar with how that works, but that’s basically where they
have a plastic solution. And they cross lasers
to solidify it and build this piece. Not out of thin air but out
of thin plastic, fluid. They call it SLA,
stereolithography. Don’t know what the
A stands for. Maybe it’s a Canadian process,
I’m not sure. Stereolithography, eh? And then you saw
the mainframe. This is a bonding fixture. Part of the prototyping is
figuring out that the tooling and proofing it all out. The bonding ficture’s quite
large in order to hold the whole frame and bond
everything into alignment at one time. And the nice thing about
carbon is it can’t be bent or deformed. So once it’s bonded in alignment
in the fixture it’s in alignment for life. But that means you better do
it right the first time. So that’s actually where the
stays and the dropouts are being bonded into the main
frame on this fixture. Not real fancy stuff,
but it’s effective. And it’s made for production
speed. Finally, once the basic
prototyping is done we do a whole battery of structural
testing. At Kestrel we pride ourselves
on having really stringent test requirements. I know Pia was concerned with
that on carbon fiber products. And we actually agree, so the
testing that we do is the kind of stuff that was done on 1970s
era heavy duty steel bikes and 10 speed
type frames. So we surpass all the
different government requirements, whether it’s
US or Europe or Japan. Our tests meet or beat
all of those. Of course, the test machine is
vertically oriented, so it’s actually pushing the frame down
to simulate a load at the front wheel axle. And it’s like a frontal
impact load. It’ll take, say 800 pounds and
up to cause any kind of structural damage to the
frame in that way. On some bikes, particularly the
tri or the Aero bikes, we also do wind tunnel testing
from time to time. This is that Airfoil Pro
that we saw some of the development images. And it’s being set up at
the low speed wind Tunnel down in San Diego. This is our top pro
triathlete. His name is Chris McCormick. He’s actually quite
a good triathlete. He won about three or four
triathlete of the year honors for his 2006 accomplishments. And one thing we did in 2006
was get him off his a more conventional seat tubed bike
onto this no seat tube, super aero Airfoil Pro bike. And what we found is that just
the frame and fork, what we call frame set, alone saved him
about 100 grams of drag at 30 miles an hour. Which is basically, if you rode
25 miles, or 40 km, in one hour it would knock a minute
off of that time, just the drag savings there. The other thing is that this
bike is designed to put you in a very aerodynamic position. And the position change knocked
another 100 grams of drag, so another minute. He can go way more than 25 five
miles in an hour, but say I was going 25 miles and in a 1
hour ride, now it would take me 58 minutes. Aerodynamics in triathlon and in
pro cycling, especially the time trial stages that I’m sure
all you folks have seen on TV and the internet. The time trials are a pretty
big catch word these days. It’s exciting to watch and the
bikes are crazy and expensive. So it really is important what
you do aerodynamically. The result, he was the
best triathlete in the world in 2006. He won, I think, all but two
races that he entered. He got second place
in those two. And he really proved what we
showed our development and in our wind tunnel testing
worked. Ironman Hawaii, the big race
of the year, he got second. I think he was a minute
and 11 seconds behind the guy who won. So one of the, I think,
third closest finishes in Ironman history. We’re looking for him to
win the race this year. But definitely what we did in
the wind tunnel and his positioning has helped him move
up from sixth place a couple years ago, second place
last year, and bringing him right down the neck to
take first this year. And that is the presentation. We have a few minutes open for
questions you folks may have. Feel free to check out
the bikes as well. AUDIENCE: You might have mentioned this in the beginning. How many frames do you
produce in a year? PRESTON SANDUSKY: How
many frames do we produce in a year? It’s actually confidential
information. We’re a small company. We make bikes, now this
year we make the bikes from $1999 and up. But we’re very much a specialty
manufacturer. So it’s really competitive,
that information. But we make in the range of a
few thousand frames and bikes a year, not tens of thousands. Yes? AUDIENCE: So if carbon is so
much stronger than traditional metals, how come you don’t
see it in mountain bikes? PRESTON SANDUSKY: I’m sorry,
why don’t we see mountain bikes, did you say? AUDIENCE: Yeah, [INAUDIBLE]
carbon frame mountain bikes are [INAUDIBLE]. PRESTON SANDUSKY: The question
is why, if carbon’s such a strong, good material,
why don’t we see more mountain bikes? And I think the simple
question is you are going to see them. More companies are using carbon
for mountain bikes now. And more companies that we’re
aware of are actually heading that way. So if I talk to a company that
just makes mountain bikes I say, dude, you have
to go carbon. If you don’t do it somebody
else is going to beat you to it. So it’s actually a great
material for mountain bikes. But just like in road bikes
where it took awhile for it to gain acceptance, it’s the same
thing in mountain bikes. And then maybe even more so
because people are worried about, people crash all the
time, or they’re worried about rocks and things kicking up
and hitting the frame. We have made carbon mountain
bikes since 1988, and I can tell you that they’re
pretty bomber. We tend to make them a little
heavier and a little thicker and tougher. They’ve been very successful
over the years. But it’s more of that
acceptance thing. Another thing is that when full
suspension became really prevalent, some of the benefits
of the ride quality of carbon aren’t as noticeable,
because you have big, fat, soft tires and
you have suspension. So you just want it to be a
super stiff structure because suspension’s giving
you the comfort. And you tend to don’t want
it to be too expensive. So carbon fiber, the price
is working down. The design, the whole thing
is coming that way. And I think, just like if you
watch the Tour de France now and there’s virtually no bikes
that are made of metal in there, whereas 10 years ago most
of them were metal and 20 years ago all of them
were metal. I think you’ll see that
in mountain bikes. Yes? AUDIENCE: What is the
disadvantage of not having the seat tube, other than
that that it’s not legal for UCI races? PRESTON SANDUSKY: Like
why don’t all bikes not have seat tubes? Well, you’re right. The biggest issue is UCI/USCF
racing regulations. A bike pretty much has to have
a seat tube to be legal. As a result that really limits
what we can do design wise, because we can make the
triathlon bike specifically for, and not care if
it’s UCI legal. So we can do that and I wouldn’t
say target it to that audience, but actually make
it for that audience. Make those people as fast
as they can be. But on a road bike or a bike
for the general population, the marking of that and what’s
accepted and what people are looking for, it becomes very
complex to go against that. It makes a great ride. I can tell you, if you have a
road bike and it’s designed properly without a seat tube,
like one of those first slides I showed you, it’s a
phenomenally riding bike. At the time that 500 series
frames were made it was actually the stiffest frame
that we made in the bottom bracket, but also the smoothest
riding bikes. We have to go with what the
market wants, and definitely the UCI rules do
play into that. In terms of the structural
part, that frame also had aerodynamics built into it, the
aerodynamic tube shape. So whenever you go for those
kind of things you’re going to lose a little bit on the
structural efficiency. So I would say if you wanted to
make the absolute lightest, stiffest frame you’re going
to generally want a triangulated frame. But the frame I showed you
there, that weiged 2.9 pounds in 1992, 1994. So you could get really close
to two pounds, just like the triangulated frames are now. Thanks. Yes? AUDIENCE: So let’s say you
have a carbon frame. At what point do you look at the
frame and say, I have this nick or this gouge, or the
neck’s kind of damaged in [UNINTELLIGIBLE]. I need to get a new one. PRESTON SANDUSKY: His question
had to do with, basically, how do you tell if there’s any
damage to the carbon frame, how do you know? And how do you know if it’s bad
enough to be a concern? And that’s another thing. 20 years ago, when Kestrel
started, there was this whole learning curve on all of that. We felt we were teaching the
industry, the bike shops, the consumers about carbon
fiber in general. And then over time, obviously,
we, and then more and more people, have manufactured,
have used it. So it’s come to be accepted. And people have learned how
to identify those things. I would say that damage
tolerance in a bike frame is very dependent on the weight of
the frame, not so much the material of the frame. So any time you’re pushing
that weight way down– The way to make a bike
frame light is to make the walls thin. And so when you start doing that
it’s going to become less damage tolerant, no matter
what you do. And so with carbon, we’ve
actually seen things where in, say a criterion race, and people
have gone down and five guys crash in a pile up. They get up, three of them have
steel or aluminum frame that’s bent and they can’t keep
riding, but the guy on the Kestrel or the carbon
frame could. So what I see in carbon is when
it gets generally slammed it’s really good, because
it doesn’t bend. But it is different than metal
for localized impact, especially sharp stuff. Not so much the big stuff,
because metal tubes dent, too. They’re damaged by the same kind
of things, but the damage is different. So to answer your question,
usually you’d take it to the bike shop that’s qualified to
look at it, and/or send it to the manufacturer. We’ll get people, I crashed. And they’ll send us a digital
photo of some damage where the handle bar came around and
smacked the tube or something. Start from there. I think that’s about all the
time we have. Thanks a lot for coming and for the opportunity.

23 thoughts on “The history and development of the Carbon Fiber bicycle…

  1. Kestrel still makes great bikes. I've owned a kestrel talon for 6 years and it is a great ride and really soaks up the road.

  2. The Graftek Exxon was the first carbon fibre bicycle way back in 1975. They also made the first carbon fibre tennis rackets, golf clubs and fishing rods.

  3. Carbon fiber bikes might have a lot of advantages but they don't seem to last near as long as a well built steel frame by a custom builder. It is common for a pro cyclist to break or crack their carbon frame at least 2 or 3 times per year. The frames also seem to have a fatigue factor making them lose their stiffness after a few years. It is also well known that your $2,500 frame will be toast in a big crash, unlike with many steel frames. If a steel frame gets damaged, its easy to replace tubes

  4. The Graftek was carbon tubes glued together using lugs on the end of the tubes. I think this guy's point about being first was that it was the first all carbon frame with no metal used to connect the tubes. That's my guess anyway.

  5. It would be nice to be able to download the slides.

    Kestrel bikes are inexpensive too. I thought that they must be an OEM bike maker – that just puts the bits together – from their prices, but in fact they lead the design of the things.

  6. The guys that started Kestrel actually worked at Graphite Technoligies who were makers of carbon fiber frames and then went on to form Aegis, so his argument of Kestrel being pioneers of carbon fiber frames is kind of a hard pill to swallow. If you look at the first bike slide, the "Kestrel 4000" it very much looks like a Graphite Technilogies frame that was used for the first Trek 5000 carbon frame, Profile,Basso, and many others.

  7. The guys that started Kestrel actually worked at Graphite Technoligies who were makers of carbon fiber frames and then went on to form Aegis, so his argument of Kestrel being pioneers of carbon fiber frames is kind of a hard pill to swallow. If you look at the first bike slide, the "Kestrel 4000" it very much looks like a Graphite Technilogies frame that was used for the first Trek 5000 carbon frame, Profile,Basso, and many others.

  8. The first carbon fiber bike (w/ metal lugs) was the Exxon Graftek G-1, that was used by the 1976 Olympic team and later sold to the public.

  9. Socrates1320 is right on! I was employed by F.H. Appel Company from roughly 1973-1975. We did indeed design and develop the first carbon fiber bicycle frame. Frank, Jerry Collier and myself designed the frame as contracted by Richard and Bill of Graphite USA. I personally did the mechanical design of the frame and drew it by hand on a drafting board. Exxon frame tubes not all carbon. Sorry Kestrel, you make some nice bikes but you need to do your history homework before making claims!

  10. My apologies to Kestrel, the Kestrel video does mention the early carbon fiber frame development correctly in their video. Many options for eliminating the lugs were discussed but not implemented by F.H Appel during Graphite USA prototype development including frames wrapped entirely on an internal mandrel that could be removed after layup. Our frames were never put into retail production. Kestrel bikes are the best carbon production bike you can get.

  11. You ask about F.H. Appel one piece carbon frame technology. We were working on wrapping an entire frame in one piece around a removable mandrel that resembled a streamlined version of the conventional steel frame. The research revolved around finding a low melting temperature metal for the mandrel that could be melted out of the one-piece carbon fiber frame as one of the final production steps. A few metal lugged carbon bikes were made for prototyping, no one-piece frames were made.

  12. The first Carbon Fiber bikes were developed by FES in (East-) Germany. Gold medals in track cycling were won during the 1980 and 1988 olympics on FES bikes.

  13. The tensile strength slide is wrong (at least according to wikipedia, reynolds site, everywhere else on the web). Look up the wikipedia on ultimate tensile strength for the correct numbers.

  14. He clearly says "Kestrel was the first to make an all carbon fibre bike on a production for sale basis" and you could buy that bike in 1986 from the high street. FES B87 German Track bike was 1987 a year later and I don't believe was ever production bike available to buy by the public in a bike shop. F.H. Appel wasn't production or available and Exxon Graftek G-1 wasn't an all-carbon fibre design. The fact remains, Kestrel 4000 was the first all carbon fibre production bike available to simply buy just like any other bike in a bike shop and that was 1986.

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