"Bill Bushnell" <[email hidden]> wrote in message
news:[email hidden]...
Quoted message said:Freewheeling said:No, I don't buy it. I'm not talking about riding a conventional
centered position, but reweighting the way pros do on technical
descents, which is simply impossible on a recumbent. Can't be
done. Very few sportif riders do this of course, so your comments
may have some validity in that sort of situation... but under
typical road racing conditions against pros? No way.
Models with upright seating positions (e.g. Easy Racers) allow one a
fair degree of freedom to shift weight. I often lean forward when
descending to put more weight over the front wheel or backward when
ascending to maintain rear wheel traction. Doing this is necessary
when one is riding on dirt roads or trails where traction is
uncertain.
Pros are pros for a variety of reasons, but outstanding technical
descending skills is not high on the list. Road races are seldom won
on a technical descent.
Quoted message said:I was involved in that discussion. Take a piece of standard plywood with
the long edge on the ground, and with some pegs close to the floor to
stand
on while you straddle it, and something iike handlebars attached to the
top
to hold onto. It's not difficult at all to imagine balancing such a
divice,
although you'd have to get the hang of it. Now try attaching a recliner
to
the top edge and see what happens to that balancing capability. Of
course
this is in a static situation... but it's the essential reason that DFs
are
"more maneuverable."
I agree that DF's are easier to balance and to maneuver at low speed.
At higher speeds, the time required to right oneself from a fall (an
initiation of a steering input) becomes shorter as forward speed
increases. At some forward speed this time becomes short enough that
the operator does not find it difficult to maintain stability. On
most DF bikes, this speed is close to zero. On most LWB recumbents
this is near walking speed. At typical descending speeds this kind
of instability is irrelevant.
I stand by my earlier statement in this thread that technical
descending speed is dependent mostly on the operator's knowledge of
the road, skill on the chosen bike, and risk tolerance.
Bill:
And I stand by my observation that those elements of balance and control
relevant at low speeds are also relevant at higher speeds, though the
feedback characteristics may be more subtle. I also think there are a lot
of pro cyclists who would disagree with the implication that descending is
relatively unimportant, though its clearly outweighed by other factors such
as climbing ability. Of course technical differences between riders on
descents are minimized because everyone basically rides the same bike and
muscular power and endurance are both less critical.
I'd also say that the idea that a modest increase in speed is all that's
necessary to bring "handling" on rollers up to match that of a DF is just
amusing, if you've ever actually tried it. Indeed, one factor that plays
no role at all on DF bikes was nearly insurmountable on a recumbent. The
regenerative feedback of the pedaling motion that tends to amplify and
bounce both bike and rider off the rollers at certain frequencies (about 60
rpm for me on the V-Rex) takes quite awhile to overcome, since modulation of
a translated horizontal motion seems to be a great deal trickier than
modulation of and compensating for the feedback of a vertical motion. (The
horizontal motion translated into a vertical amplitude that was nearly
impossible to control.) I eventually overcame the problem by practicing to
acquire an exceptionally smooth pedalling stroke, and I also began using
slightly shorter cranks. At some point I simply "broke through" the 60 rpm
barrier, and above the critical frequency the feedback disappeared.
But this was just one of a number of rather unexpected emergent
difficulties, and basically I just concluded that we're probably designed to
move better, and more effectively, in an upright position. It's not that
one can't compensate, and ride a recumbent well, and fast. But all else
being equal maneuverability of a DF is just significantly greater than a
recumbent. And obviously the more reclined you are the more pronounced the
difference.
The primary advantage of recumbents is their lower aerodynamic drag. I'd
also say that they're more comfortable for longer rides, which is probably
true for the average rider. But this latter advantage seems to disappear at
distances much greater than 100 miles. According to some members of this
list who ride randonneur events on both recumbents and uprights, the
recumbent is just as demanding, if not more so. (I can't verify this
myself, so have to rely on their testimony. I'm insufficiently insane to
ride in randonneur events.)
Quoted message said:
--
Bill Bushnell
http://pobox.com/~bushnell/