In simple terms of arithmetic, some of these differences are
negligible.

If you take 150 as a 'bench mark' then:
145mm = 3.3% shorter
140mm = 6.7% shorter
160mm = 6.7% longer.

Of course, the difference between the shortest and longest on your list
is significant: 160mm is 20mm longer than 140. 160mm is around 14%
longer than 140mm.

So, if your ideal would be around 150mm, you will be choosing between
very slightly shorter and faster, or very slightly longer and torquier.
It's a fine tuning thing, and there will be few circumstances in which
you really notice the distance.

The longer cranks will give you a touch more torque when slogging up
hills, or when doing slow and controlled descents. The shorter cranks
will give you a touch more speed, so you will be able to rush short
slopes.

Longer cranks might be slightly more likely to snap or bend on a drop
because of the longer leverage. I have no experience of drops.

The maths isn't everything, though. There's an ergonomic factor to
consider: what size fits your legs best? I know many MUniists like
170mm cranks. I just couldn't get on with them, and I'd rather use 150s
and walk a bit more.

Whatever size you buy between 140 and 160 will feel like the "right"
size as soon as you've used them for a while. Remember that every
unicycle is a compromise. Part of the fun is getting the compromise
right; part of the fun is making the most of it.


--
Mikefule - Roland Hope School of Unicycling

Sometimes I ride like a demon, sometimes like a lemon. It's an L of a
difference.
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