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This is the roughed-out yellow birch
plank - the start of the wood portion of the frame
(2/20/97) |
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Same plank drilled out to reduce weight -
4lb. 12oz. (2/22/97) |
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The front end of the 'frame' has been
bored out to match the modified head tube (parallel
4" extensions which will be cross-pinned into frame) |
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'Reconfigured' rear triangle from old
Trek 400 upright bike. Seat tube cut to 8", seat
stays bent down to mate to it, top of seat tube and top
tube brazed on to provide adjustable suspension (trust
me). This thing weighs in at 3lbs. 8oz. Completed rear suspension detail
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Rear suspension pivot detail. Bottom bracket has been
left stock except for amputation of the down-tube.
Standard bearings replaced with some sealed 30mm x 10mm
bearings I had laying around. A perfect fit inside the
old bearing shell. A grade 8 bolt, some washers and
spacers completed the pivot. |
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I cut out 4 ¼" of fork to allow the use of a
20" front wheel. This size chosen for its
availability while on the road. Lucked out here (I hope)
in that the lower portion of the fork leg fit up into the
upper part so I'm not relying solely on the braze job.
The dropouts had to be adjusted to acommodate their new
angle at the axle. As you can see, I'm planning on using
the old sidepull brakes. Inexpensive alloy rim and hub
with 20"x1.5" 80 psi Kenda tire. |
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Made some progress on the headset mount. After a
little carving on the end of the frame the headset unit
fits and is ready to be pinned into place. Dilemma... pin
through the yellow birch only; would look better because
cherry sides will hide the ends of the pins, or wait and
run pins through sides also; not so cool looking but
serviceable. (3/1/97 am) |
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Discovered that I have a similar decision to make on
the bottom bracket. The vertical tube (seat tube in a
previous life) is larger and probably needs the strength
of the laminated cherry sides. So, guess I'll be
consistent (and conservative) and use through-pins. These
will probably be 5/16" steel and friction-fit. (3/2/97 pm) |
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(4-7-97) Well, it's
hard to believe that the bike (now named 'Woody') is
almost completed. As you can see from the picture, we
still have lots of snow on the ground so I have not had a
chance for a test-ride yet. The seat is the only big
project left. The old Maxam seat is mounted now but it is
steel-framed and the new one will be aluminum as well as
trimmed down a little in size. |
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The rear suspension seems to be working OK but a road
test will tell the tale. This design and my conservative
nature caused the suspension to add over 10" to the
length of the bike. It could have been done more
compactly but I decided to go with strong rather than cut
any corners here. The shock elastomer is silicon sealant
in a bellows-like tube inside a steel tube. I found a Manitou
shock boot fit it just fine. |
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The front end went together pretty well, though I
consider the weak link in the project to be the front
fork modifications. On the next bike I will be sure to
arrange it so that the lower part of the blade will be
inserted farther onto the crown end of the blade. Only
time and miles will tell how durable the present fork
will be. |
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I Set the bike up on the rollers today and took it
for a ride. Came up with two problems; Buzzing vibration
from the idler pulleys used to guide the chain under the
seat. The drawing at left shows what I thought would
work. What is happening is that the chain, which is not
under a lot of tension, kind of rides up and down on the
teeth of the pulleys. Any ideas? The vibration caused by
this arrangement is very objectionable as it can
both be heard and, especially, felt in the pedals. |
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The second problem is that due to the unreasonable
length to which the bike grew while I wasn't looking, I
had to join two pieces of shifter cable to reach the rear
deraileur. I cobbled something (left) but later found
that Tandems, Inc. has a cool link that is designed for
use with folding bikes. They also have tandem- and
triple-length cables. I continue to use the one pictured. |
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(4/14/97) Well, here
is the current solution to the chain noise and control
problem mentioned above. Though the drawing doesn't
really show it very well, what I've done is rework a high
density polyethylene tool handle (recently replaced with
3/4" PE tubing) into a tubular chain guide. The tube
is about 6 inches long and is very smooth inside. It is
mounted by wraping a section of rubber shock strap
material around it and fastening that to the old chain
guide bolt. Due to the combination of slippery material
and rubber isolation mounting it is both quiet and smooth
in operation. Again, time will tell how it will hold up
but for now it works! (Still cool after
700 miles - 6/98) |
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(6/23/97) Woody has just
under 400 miles on him and is just about completed (as
much as a homebuilt, evolutionary bike ever is). Weight
with the new aluminum seat, complete with fenders, rack,
etc. is 37 lbs. Weight distribution is 40/60, Front/Rear.
I ended up installing a new rear wheel with a 700 x 41C
cross tire and a 11 x 32 7-speed cassette. With the
24,38,50T chainrings Woody has a range of about 22 to 126
gear inches. - Almost time to get to work on bike #2 for
Sue (She is riding the 44 lb. Maxam and is ready for her
new under-30 lb wood recumbent). |
