Re: square tapered hub?

A square tapered hub is the basic hub. The square tapers are the ends
of the spindle (you might say axle). They are tapered so that the
cranks can slide on. The cranks are then held on with either a bolt or
a nut, and covered with a plastic dust cap.

The whole effect is pretty similar to how a normal cotterless chainset
is attached to the bottom bracket spindle of a bicycle.

The advantage of a square tapered hub is it's simple and cheap to make.
It is perfectly adequate for normal riding - even quite hard. Bear in
mind that many bicyclists ride hundreds or thousands of miles at high
speeds and high levels of torque using the square taper system.

The disadvantage is how it might react to sudden heavy loads - as in
drops. If you do a drop, your momentum is transferred through the
pedals to the crank, and comes out of the other end of the crank as a
twisting force on the tapers. Think about this: your cranks are
horizontal, so as you land, you're twisting one crank in each
direction.

On a square taper, all of that twisting force is borne by four narrow
strips of metal near to each corner of the taper. You can round or
twist or otherwise damage the tapers.

The alternatives are:

Don't drop.
Drop with more skill and delicacy.
Get a splined hub.

A splined hub is more expensive, but it spreads that sudden force over a
greater surface area. Instead of a square taper, the end of the spindle
is toothed or splined, like a cog, and the socket in the crank is a
female version of the same. Harder to make, harder to break.

How big a drop will it take? That must depend on too many variables,
amongst which I'd include your bodymass, your technique, your tyre
section, your tyre pressure, the number of drops you carry out, how well
you maintain the unicycle... but you will find that a splined hub is
more durable.

In the west, if we cannot hit the target, we make more complex and
expensive bows; in the east, they practise until they can hit the
target.

--
Mikefule - Roland Hope School of Unicycling

Well, it all depends on what you mean by "semantics".
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