I finally rode the laminated wood and fiberglass unicycle with the 3 by 26 inch
tire that I have been building for months. It is great. The big tire rolls over
bumps with ease and bounces like a dream. Even though I weigh 225, I can ride
comfortably with 22 lbs of air pressure and no sideways give of the tire when I
bounce. The unicycle is very stable and is stiffer and heavier than necessary.
As near as I can tell from the bathroom scale, it weighs fifteen pounds,
complete. I plan to start another model soon with thinner forks and heavier
fiberglass and I hope to lose a pound or two. It does not turn easy due to the
large footprint and increased traction. Mostly all I have to ride it on here is
rough ice and snow, but I did bounce it up and down several sets of stairs. Some
of the ice bumps are six inches high.
Milling the bearing seats directly into the wood went very well but when I bored
the seatpost hole, the 7/8 inch ship auger bit I was using did not quite follow
the 1/4 inch pilot hole I left for the lead screw and the seatpost is a bit off
center. I was so worried about milling the bearing seats that I did not pay
enough attention to boring the seat post hole. Perhaps next time I shall leave a
pilot almost as big as the final size, and bore with a large jobber bit. I made
the bearing blocks from maple, 3 and 1/2 inches long and screwed them directly
into the end grain of the wood beside the bearing with four inch grabber type
screws to get the threads well up into the fork where the fiberglass will
hopefully prevent splitting. Time will tell.
I am riding with old 175 cranks borrowed from an old Zuess bicycle that I have
in the garage, and they feel good except that they have odd pedal threads and I
am forced to ride on the one sided road cranks. The frame is over 3/4 inches
thick and barely fits between the crank and the hub. I shall be trying to find
some 180 cranks. My calves do rub the frame a little bit but it is wide and
smooth so no problem except it will no doubt wear off the paint if I ever get it
painted. The epoxy needs to be protected from uv light so I will need to paint
it soon. A bigger problem is the too long seat post bolt that rubs my legs. I
shall be trying to find some sort of recessed bolt, like a seat post bolt from a
bicycle only longer.