>I want one really bad and I had the same idea as you, find a Schwinn replica
>penny farthing. Tom could build me a custom big wheel uni if I give him about
>$500, but that's not going to happen any time soon.
>He told me how he made his first ones, back in his high school days.
>He made his own hubs out of small kids-bicycle chain wheels by cutting
>the teeth off and drilling spoke holes around the circumference. He welded
>two of these to a steel bar 5/8" in diameter and filed flats for cottered
>cranks. The spokes were simply lengths of steel wire with spoke threads
>rolled into one end and a "dogleg" bent into the other end. The rim was made
>by cutting and carefully uncurving two or three 26" steel bike rims and weld-
>ing them together. The tire tread was simply a bulk length of wheelchair
>rubber held on by an internal wire and glue. The frame was easily made
>Schwinn-style with two pieces of flat bar stock.
Back in 1980, Tom helped me put together a 40" big wheel right after
he finished his duties as the 1980 National Unicycle Meet Director!
In the few years thereafter, I put together close to a dozen big wheel
unicycles in sizes from 34" to 56", using Tom's basic design and a
local machine shop to do the frame and weld the rim pieces together.
Hub flanges can be made out of 16-18 gauge 5" disk plates with 5/8"
hole in the center for the axle. I had a jig made so the spoke holes
could be drilled at the exact same radial distance. A paper plan of
where the spoke holes should go can be taped over the top plate and
drilled into with a drill press. After the holes are drilled, a
de-burring tool can be applied to each side of every spoke hole.
The axle must be made of cold rolled steel so it will be hard enough
to last a long time, but if it is too brittle the axle can crack or
break. It would be best to find out exactly what axle material Tom
uses. It is easiest to cut notches for cottered cranks in a mill.
Be sure the flange spoke holes are staggered properly before welding
them on the axle. After the flanges are welded to the notched axle,
they can be painted a silver, aluminum or chrome-like color or
actually chromed.
3/32" x 36" stainless steel welding rods make excellent spokes with an
old bicycle style S end on one end and 3 56 cut threads on the other
end. This makes very close to a 13 gauge spoke. 13 gauge nipples are
somewhat hard to find, but are available. Schwinn had a big supply of
these. Now Semcycle might have a supply of these or may be able to
make a referal to a parts supplier who does.
27" x 1 1/4" Schwinn tubular rims are excellent raw materials for
making big wheel rims by cutting at the spoke hole and slowly
increasing the radius and matching to a circle of the desired wheel
size on a large sheet of cardboard. Using 36 hole 27" rims, the
possible big wheel rims are:
No. of Holes Wheel size in inches (approximately +/- 0.25")
48 34.25"
52 37"
56 39.75"
60 42.5"
64 45.25"
68 48"
72 50.75"
76 53.5"
80 56.25"
Wheel size above includes a total of 1" wheelchair rubber, 1/2"
sticking out on either side of the rim, so outside diameter rim
measurements will be 1" less then the size given in the above table.
Use the hardest grey wheel chair rubber in the 7/8" diameter size.
Use 11 gauge steel wire inside the wheel chair rubber. A gapping tool
is placed between the ends of the rubber to keep them apart while the
wire is tightened until the wire makes a somewhat high pitched sound
when picked. Twist the wheel 180 degrees in the direction that causes
the wire ends to wrap around each other. Cut the wire carefully to
the length of the gapping tool; make sure the wires don't unwrap until
the gapping tool is removed and the rubber ends can be pushed around
the wrapped wire ends. WD-40 or another light lubricant is used to
get the wire through the hole in the tire and to slide around the rim.
The rubber should be cut 12-16" longer (depending on wheel size) than
the circumference of the wheel, so the compressed rubber will close up
the gap between ends and also so the ends won't separate during normal
use of the big wheel.
This was not intented to be big wheel build it yourself guide, but it
has gotten close to it in some respects. Just wanted to add enough
information for any would be big wheel builder to seriously consider
building one. It's not that hard to build a big wheel to equal the
quality of one built from a penny farthing replica!
Stay on Top,
Ken Fuchs <kfuchs@winternet.com>