Building
A Custom Carbon Bike Part 5
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| February
9,2003 |
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| Ready
to roll! My project is complete less paint. I plan to put on some 2-300
miles to test all aspects. I did, however, fall a little short of my goal
weight wise. I was hoping to achieve a sub 20-pound bike. The actual
weight (without pedals, headrest and computer weighed in at 20 1/4 pounds.
The main reasons are as follows: The frame was at least 1 pound heavier
than it should have been, the seat was more than I would have liked, and
the rear HED wheel, while advertised at 800 grams was 940. In due time, I
will shed weight and achieve my goal.
All photos (except those pointed out)
were taken with a new Canon S30 Digital camera. Hope the improvement is
obvious. |
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| This
was the reason my project started. This is my trusty Optima Baron that has
15,000 miles on it in 2 years 4 months. Of all the bikes that I have
owned, this is the most versatile, fastest, most comfortable and my bike
of choice under most conditions that I ride. I just want a lighter bike! |
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| This
is the bike shown from the rear. I am using the carbon-modified fork and
wheel found on this web site. A new HED rear wheel (650) was purchased, as
well as a new seat (discussed later) and Murray adjustable cranks.
Titanium or aluminum fasteners were used throughout. |
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| A
view from the side. The frame is probably overbuilt. The nominal thickness
in less critical areas is .060 inches. In more critical areas the
thickness range from .120-.130 in the head tube area, to .100-.110 in the
boom area and the same where the rear fork joins the main frame. For sure
the rear fork is heavier than needed. This is my first attempt at frame
construction, and I did not want to compromise. |
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| This
photo is taken from the opposite side. Yet another reason for the weight
increase is beefing the frame directly below the front seat pivot. This
was discussed in previous web site discussion. |
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| Photo
taken from the rear quarter. |
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| Photo
taken from the front quarter showing the Murray Cranks. |
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| These
3 photos show the control center. The tiller and handlebar was shown at an
earlier time on this site. I mated SRAM 9 speed twist shifters and brakes.
I was originally going to use Nokon cables, but they are not available in
longer sizes for recumbents or tandems. So I went with the Ride-On
Ultralite-Fibre Opt-Shifter cables, and the Ride On Gortex Brake cable
set. The former is far lighter than the latter, and I don't see why it
cannot be used for the brake as well. Both are very nice products.
The cables were routed on the top and
bottom of the frame to the rear, and through the front boom to the front.
All cables were routed through the tiller. |
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| These
photos are taken with the seat cover removed. Shown are the lightening
holes that were drilled in the old seat (that which came with the original
Baron). Again to be discussed in more detail later |
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| This
photo shows the hardware used to connect the seat to the frame. First of
all, the brackets (available from Optima) are made of aluminum vs.
stainless steel, which came with the original. I got button head aluminum
bolts (http://www.racebolts.com/)
to connect the seat to the brackets. Two 8-mm socket head bolts are used
on the forward pivot and two 8-mm titanium bolts are used on the rear. All
from the same source. |
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| This
photo shows the Baron Carbon Clone without the seat. Very evident here is
the strengthening of the mid section of the frame. Just what was I
thinking? |
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| This
photo shows the two bikes, rear wheel to front wheel, for comparison sake.
Keep in mind that one of the rear wheels may be elevated in the
bike stand. |
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| Shown
are both bikes, front wheel to front wheel |
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| This
photo shows both bikes, Baron in front and Clone behind. |
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| This
shows the Clone in front, and the Baron behind. Note that both rear wheels
are even on ground. |
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| This
shows both bikes from the rear with rear wheels on ground. |
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| Detailed
view of front nose cone with carbon derailleur tube. I used a braze on
front derailleur, and the transition piece was made by me. |
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| Front
nose cone from opposite side. The Murray Cranks are connected to the Dura
Ace Bottom Bracket by Specialty Racing Products Titanium bolts. Expensive
but very light and beautifully machined. |
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| Of
particular interest here is the method of attaching the front derailleur
to the post. A braze on type was used. The transition piece started out as
a 2-inch billet of aluminum, and after some 10 hours of machining and
fitting, this is what it looks like. |
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| This
is what it looks like from the front. |
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| After
much thinking, fabricating and reworking, this is the method I am using to
fasten the adjustable boom to the frame. I took a high-end marine type
clamp and highly modified it. |
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| The
stainless steel clamp is made for circular surfaces, and will not conform
to the contour of the frame, so it must be modified. The clamp ends were
cut off and riveted to a form fitting carbon shoe made to the
configuration of the lower section of the boom. |
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|
These are poor photos taken with my
pre digital camera, and with a flash which I obviously do not know how to
use Shows the parts of the clamp prior to being put together. |
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| Uni
directional carbon was wrapped around the shoe and the entire boom. This
was done prior to riveting the clamp ends. It was then bonded to the boom. |
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| The
entire assembly was faired to the boom with lightweight filler and a slot
was cut in the bottom. While this clamp has more than sufficient force, I
would still like to try to make it lighter. |
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| This
photo shows the rear brake, which is attached to the underside of the
frame, unlike the Baron, which is on the topside. |
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| This
shows a side view of the rear brake. Also notice the
lightning/strengthening carbon tubes through the frame. Two larger rear
ones, and a slightly smaller one forward of them. Also, there is another
forward, but a threaded aluminum plug (8-mm) was bonded and is used for
the rear seat fastening. |
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| Now
for the front brake. The modern brake would not work in this application
because of the actuation arm/frame interference. To remedy this, I
searched the web and purchased a 60-70ish vintage brake. |
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| This
is a photo from the opposite side. For the future when the stock market
rebounds, I will replace the brakes with these. (see http://www.cat-usa.com/pages/1/index.htm) |
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| Another
view showing how the brake was installed on the rear of the fork. |
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| This
shows the installed brake and a hand held modern (Shimano Ultegra) type
brake. Notice the difference in the activation arm. This lack of clearance
is the reason it would not work without raising the bottom bracket and
changing the geometry of the design. |
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| Now
to the seat. A new seat was purchased from Optima for the project. This
weighed 615 grams in the large size. It is shown on the left. The original
seat that came with the Baron weighed 640 grams in the large size. I made
a decision to sizably reduce seat weight, which meant making a new one.
However, I wanted to test the bike without waiting to fab a new seat, so
the decision was made to drill out the old seat, and use the new on as a
mold to fab a lighter version. The drilled out old seat weighed 540 grams,
savings of 100 grams. |
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| Shown
is the main idler (only one used). The wheel is a reworked 25-tooth cog.
The frame is carbon formed on a waxed piece of wood. The tension side is
guided in a slot made from Teflon, and the return side is guided through a
Teflon slot.
For an update, this was changed. Will
report in the next update. |
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| Opposite
side of the idler. A carbon tube was inserted through the frame and
bonded. An aluminum-threaded plug (8-mm) was bonded into the opposite side
and is the attachment mode for the idler. |
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| This
is a piece of boom that was removed. This shows construction of the frame.
Each side was made independently, and the overlap in the center. The two
sides were then bonded to each other.
I am in the process of testing the
bike as I write. At first blush, after having put some 150 miles on it,
weight reduction is indeed worth it. The bike is most definitely quicker,
and only more testing will determine if it is faster overall. Very little
effort is required to accelerate to 20 + MPH. I have not (as yet) been in
a sprint mode. It is as stiff as the Baron is. The next step is to paint
it. I will go to a professional shop as I don't have the equipment, nor do
I want to learn the intricate paint process. The next update will include
all. |
