> I have a Semcycle 24" with cotterless cranks.
XL or deluxe? Semcycle needs a better naming structure for their cycles,
because this is always the first question I have to ask when someone writes
about a Semcycle. In this case I’m guessing it’s the XL because those are
wide and the deluxes are very narrow.
> 1. Is a low Q factor in itself preferable, for reasons of less wobble?
I don’t know if this has been proven in any definitive way, but common sense
implies to me that it is. Also my own experience. Some people naturally
wobble more than others, but having the pedals farther apart can’t help
> 2. Is the 1 cm spacing a necessity in the design to accommodate for
> tolerances in the square’s sizes, and/or to have some space for the
> crank to be moved further up the taper in case the holes wear out?
Alloy cranks, especially, will go farther onto the taper each time they are
used. In the long term, they will reach a point on a Miyata axle, for
instance, where they can no longer be used and stay tight. I believe the XL
just has wider tolerances. If these unicycles are spec’ed together from
existing high production volume parts, it may just be the best combination
of available parts for the price range. But yes, the XLs are wider than
This is most noticeable on the 16" or smaller models, where the Q-factor
starts looking a little ridiculous. I’m sure it wouldn’t hurt for these
cycles to be a little narrower in that area.
> 3. Bottom line question: why is there as much space as 1 cm?
Oops, think I answered that above, with a guess. I don’t think the whole 1
cm is intentional, though I would rather have too much space than not
enough. My old track unicycle and my carbon MUni both have almost too-tight
tolerances in that area.
The spokes on my track uni used to just barely clear the ends of the (Miyata
style) bearing holder bolts. I had to keep track of the top vs. the bottom
ones, because the bottom ones had been cut down shorter to fit. It was made
narrow on purpose, for speed. And though the unicycle proved to be fast, it
wasn’t always faster than a better-trained rider on a piece of junk.
My carbon MUni has very tight tolerances outside the bearing holders. The
150mm Miyata crank arms I’ve used on there have always had to be filed down
first, to keep them from rubbing. On a MUni, I would rather have a little
extra space than not enough.
Stay on top,
John Foss, the Uni-Cyclone
“This unicycle is made all from lightweight materials. But it uses a lot of
them.” – Cliff Cordy, describing the very heavy new prototype unicycle he
brought on the Downieville Downhill