The quick part first...
> This is probably a silly question, but how do you change the tyre?
> I've been look at my 24" SemCycle and couldn't see how I could
> remove the wheel. Do I need any special tools? I know I'm not
> very handy, but changing a tube should be within my abbilities.
Undo the main bolt that holds the forks to the stem. The forks will then
come apart and you can change the tyre.
Now the bigger problem...
Loosening of cotterless cranks is a common problem, but it can be solved
or (even better) avoided completely in the following ways:
* don't ride if the cranks are loose
not only does the axle eat into a loose crank and make it almost
impossible to get it to fit well ever again, but the jarring of the
loose crank against the axle greatly increases the chance of the
axle shearing off completely!
* seat the crank well on to the axle
use a *** hammer if you can to avoid damaging the thread so that
extracting the crank will be easier. Once the crank is seat firmly
in place the contact between all of the faces of the axle and the
crank should be so secure that the nut should not have to do much
* make sure the the nut doesn't start to work loose
once a nut has developed the habit for working loose it is much
harder to stop it. The best solution we have come up with so far
is thread tape, which you can wrap around the thread on the axle
before you put the nut on.
* if the parts are damaged, replace them
nuts are cheap. Worn ones are not worth the bother. If riding with
a loose crank has caused damage to the crank, and filing the faces
of the hole in the crank does not make a tight fit on the axle
possible, then get another crank. This is greatly preferable to
breaking the axle and having to rebuild the whole wheel.
* don't assume that because the uni is new, the cranks are well fitted
These lessons are the fruit of years of bitter experience both from my own
uni and those of my team-mates. The main point is that prevention is better
than cure and if you get it right first time you never need to have a
Peter Philip of the LUNIs - London's Unicycle Hockey Team
Coordinator of UNICON VIII - The World Unicycling Convention 1996