My new Coker arrived this morning. I’m still at
the office admiring it, as yet unassembled.
The frame was built by Rick Hunter, then shipped
to David Stockton (U-Turn) for assembly with his
Super Wheel. I shipped David my saddle with GB
handlebars. He took my measurements and put
together the whole package. I’ve attached a
picture he sent to tease me a few days before
it was shipped.
I’ll take it out for a moonlight ride (full moon!)
tonight on it’s maiden voyage, then provide some
reviews and feedback. I can hardly wait.
In the meantime, David included some useful
information in a detailed email after the Coker
was shipped. I found it interesting enough
that I thought I’d share his comments with this
forum. I’ve elided some irrelevant stuff.
David’s comments:
Seat: ----------------------------------------------
I rebuilt the seat, adding the stiffener plate and
replacing all the hardware with stainless steel that
has better specs than the original. On the front 3
and back 2 bolts the bolts have been retained with
nuts which should completely eliminate the spinning
problem. On the back 2 I actually opened up the hole
in the bumper to allow the nut to sit down in, then
added the washer. On the center 4 that attach to the
adapter this was not possible without compromising
the seat coupling, so they are only retained by the
traditional duct tape. There is a better solution;
I just haven’t found it yet.
Handle: [refers to GB handle] ---------------------
I had to move the cyclo mount over because it was
interfering with the brake lever. A local welder
did the work.
Cyclometer: ----------------------------------------
The cable is long enough for a little bit of seat
adjustment. To raise the seat significantly you may
have to slide the sensor and magnet up a bit. You
will see that I shimmed out the sensor to get close
enough to the magnet.
Seat post: -----------------------------------------
Should be cut properly for 150mm cranks and your specs,
so you may have to raise it a little for the 140s that
are installed. It is currently at the very bottom of
allowable travel and is resting on the cross-tube. It
is not possible to remove the top piece of the seat post
without loosening up the seatpost adapter due to the
saddle’s tight clearances. To loosen the adapter you
will have to remove the back bolt on the handle.
Frame: ---------------------------------------------
We had to do a lot of work to clean up the inside of the
seat tube. It was rough and there was some sort of hard
pin poking into the tube from the angled piece. I will
mention this to Rick. It should be fine now. The seat
post clamp is the one that came with the frame. If you
find that your seat is turning on uphills or mounts you
may want to go to a 2-bolt clamp like the Primo.
Brake: ---------------------------------------------
The brake seemed to come out very well. The bike
shop owner’s son, who has legs long enough to give
your uni a test run, preferred the feel to my
Magura setup. It seems quite smooth and modulatable.
It will change quite a bit as a) you get used to it,
and b) the cable stretches. For that reason, I
did not attempt to get the ideal setup, but just
got it into operating range. I will give you rules
to use for it though.
Setting up a brake for a uni is not the same as for
a bike. Here are some guidelines for you or for your
mechanic:
-
It is ok if you can’t lock up the wheel when
the brake is done. Unless you are doing trials,
you will never need that much braking power. You
will want smoothness and modulation much more than
power. -
You should toe the brakes in much more than a
normal brake. This improves modulation. -
One pad should hit the rim significantly before
the other. This also improves modulation. -
You should move the brake pads out just enough
to ensure that the pads do not hit the rim during hill
climbs. The Super Wheel is absolutely the best going
in this regard because it is far stiffer than any other
big wheel arrangement. On your setup, one pad brushes
the rim slightly in one spot. I left this because I
knew that the cable would stretch.
Getting used to using a brake on a uni is different too:
-
I recommend riding on the flats and just feathering
it on to begin with. Despite all your attempted finesse,
you will probably lose it the first couple of tries
because of all the bicycle habits. My first brake
application was on a country road hill and I few
about 12 feet through the air. -
In order to get best use of the brake you need
to start using at the top of the hill so that your
balance point includes the brake drag. Trying to
use it in the middle of the hill doesn’t work because
you have to speed up the wheel to keep the brake from
pitching you forward. -
A mental image that is helpful to me is to think
of the seat post as a skid that I am digging into the
road as I apply the brake. I have to get behind neutral
balance and push the bottom of the seat post ahead of
me into the road. This image helps get my weight back
and down, so that the braking action works against
my weight. -
Although your setup is not a drag brake, that
has advantages on rough downhills because you can
use the brake as an additional balance achiever
instead of just a hill-flattener. Eventually you
will use it all the time to save your legs, even
on such mundane matters as coming to a stop. -
A uni brake doesn’t stop you, in contrast to
a brake on a bicycle. A brake on a unicycle is like
a power assist for your legs. It allows you to travel
downhill more safely, and allows you to get out of
the hill some of what you put into it.
Wheel: ---------------------------------------------
I think your wheel came out quite well. You can see
that I worked on the weld area as you requested.
Basically, that activity results in an area of the
rim that is of less width and less friction than the
rest of the rim. These characteristics, for a uni
brake, are far more desirable than the original,
which is a protrusion of higher friction where the
brake tends to dig in. An area of higher friction
is much harder to control and much more disruptive
of fore-aft balance. So, in general, there will be
some minor variation in braking force during a wheel
rotation.
I used sleeve retainer on the bearings. If you remove
them chances are they will no longer be good, so I
suggest leaving them until you are ready to change
them. If you ride off-road or in sandy conditions
they will deteriorate much faster.
I have included two spare spokes. The installed
spokes use Wheelsmith Spoke Prep. The tension is
VERY high and I suggest that you either return the
wheel to me for truing (no charge, including return
shipping) or go to a really, really good bike shop.
I think you will notice a huge difference between the
feel of this wheel and that of your stock Coker.
Cranks: --------------------------------------------
The cranks are the Schwinn 140s. They do add a little
more Q to the leg position but you should not notice
this as a problem. The 125s, which are straight, are
in the box. I highly recommend the grease/torque
wrench approach to installing cranks, using 40 ft-lbs.
Please do not use a hammer at all. I have had customers
bend hub flanges in this way. If you need me to elaborate
on the installation procedure just ask.
Pedals: --------------------------------------------
The pedals will have plenty of grip. After a while
take a file and flatten off the pins and your traction
will improve once more. I recommend using blue Loctite
when you install the pedals.
Tire: ----------------------------------------------
I deflated the tire somewhat for better shipping
protection. You will, of course, want to repressurized
it before riding. If you need instructions about
changing the tire please let me know. The tire on the
Airfoil rim is actually easy to change if you know the
right procedure. I used talc between tire and tube. The
rim tape is Salsa 100% polyester.
) that he could get down to a 3" tube. I think he changes the angle of the slanted tube to do so. I may have to do this myself because my legs are happily short. I couldn’t ride Jeff’s, for example.