U-Turn said:This is a common misconception. Smaller wheels are not inherently
stronger than larger ones, just as smaller bridges are not inherently
stronger than larger bridges. Wheel strength is a complex combination
of component choice, design, and quality; wheel geometry; and wheel
build quality. Wheel strength has little to do with size.
I believe everything in your penultimate sentence goes without saying,
although in my earlier post I /did/ state that: "the larger wheels that
we now see on some mountain bikes are the result of huge advances in
the quality of components over the last 20 years".
Because I CBA to hunt for specific evidence, I'll resort to arguing by
appeal to (strong) authority. Mike Burrows (one of the highest
authorities on bicycle design issues) states quite categorically in
"Bicycle Design", referring to wheels, that "smaller is always
stronger" (the issue of component choice is implicit).
More interestingly, Jobst Brandt states in "The Bicycle Wheel" that:
"Because wheel strength is closely related to the number of spokes in
the load affected zone, the number of spokes per length of rim is kept
about the same for different wheel sizes. A large wheel must have more
spokes than a small wheel to achieve the same strength".
Again, this means that all other things being equal (particularly the
number of spokes, which is a factor in wheel design), a smaller wheel
will be stronger. Small wheels /are/ inherently stronger than large.
As far as the OP's mum is concerned, he might be better off pointing
out that he's unlikely to find a 16" wheel that is as well built, or
built with the same quality of components, as the wheel on either a 20"
or 24" KH. I would also hope that he has other reasons for preferring
a 24" wheel - strength is presumably not the only consideration when
choosing a trials unicycle.
--
Danny Colyer
http://www.colyer.plus.com/danny/
"He who dares not offend cannot be honest." - Thomas Paine
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