[email protected] wrote:
> David Damerell writes:
>
> > Lately I have had the urge to get a penny-farthing. I'm wondering if
> > any r.b.t. types already own such bikes, or know of competent
> > manufacturers - Google suggests some people still make them, but are
> > they any good?
>
> No.
>
> Consider that most bicycling on the level is done in a gear above 85
> inches (the way gears were measured in respect to these bicycles)
> which means a wheel diameter of 85 inches. A 52-13 for instance is a
> 108 inch gear for comparison. Your inseam minus about 2 inches times
> two is the largest wheel radius you can ride. That's about a 62 inch
> high wheeled bicycle. You'll need to do a lot of spinning.
The only single-speed bikes geared as high as 85 inches are those for
the velodrome, which has no hills, corners, or bad surfaces. A BMX
bike typically uses a 55 inch gear, a single-speed MTB about 52
inches, and a balloon-tire criser anything from the mid-50s to the
mid-60s.
When I was exceptionally fit and I lived in the gently rolling terrain
of Austin, Texas, I used an 81 inch gear on my fast cruiser. Here in
hilly Seattle, all my one-speed bikes sport something around 64 gear
inches-- even the fixie.
By using shorter cranks, one can use a larger wheel and a higher "gain
ratio" at the same time. High speed is thus available to a high-wheel
rider who opts to sacrifice hill-climbing and acceleration.
High-wheeling is by nature a more leisurely activity than your own
riding, if you use an 85 inch gear to cruise around. If you could
only choose one, though, I bet you would not ride a gear quite that
high.
> On top of that, you can't stop worth a damn because rider CG is close
> to vertically above the ground contact point of the wheel, so forward
> dismounts are a skill to master.
Another reason to keep speeds modest when riding the wheel.
> They are nice to view in museums but don't ride them. They have solid
> tires and the rider sits directly in line with road shock on no
> cushioning.
The gentle vertical accelerations imparted by a four to six-foot wheel
rolling over irregularities require none of the cushioning a squishy
tire imparts. You will remember that it was Dr. Dunlop's invention of
the air bladder tire that allowed safety bikes to come into general
use. Those were the bikes whose ride qualities suffered for lack of
cushioning.
> The riders crotch must be as close to the wheel as
> possible to get a reasonably large gear. You can imagine who won
> races in those days. They were pretty tall.
I can find no virtue in a technology on the basis that it confers a
competitive advantage to short people, Jobst. I wonder why you would!
;D
Chalo Colina
