Jeff Grippe wrote:
You have made some interesting observations. One of mine is that back in the
days when I rode DF's, I could easily ride without holding onto the
handlebars. I have never had a recumbent bike where I could ride without
holding on (I owned an Infinity LWB, Vision SWB, and Trek). The Trek, which
I thought I would love, was the "twitchiest" steerer. The Infinity, which
was the oldest and lowest end of the bikes I've owned was my favorite.

I am interested in learning how Quad's would handle although I suspect that
they could also easily go up on two wheels. Its too bad I could have a bike
that became a trike on the really steep ascents.

I guess if I'm going to stick to rail trails then I could get meself a
really good two wheeled 'bent and I should be perfectly content.

Jeff
"chalo colina" wrote in message
ups.com...

32GO wrote:

Jeff and I got a bit off the topic in the TdPS. His last
post there said:


I have no problem piloting a trike in the mid to high
20's but when I go down a hill of any decent size,
I'm very quickly in the 30's and the trike does not
feel stable.
...
...
I'm going to offer my observations based on lots of riding on upright
bikes and trikes. I have ridden 'bent bikes of different kinds, but I
must admit that they all felt dangerously unstable to me at any speed,
like they would dump me in a heartbeat if I even /thought/ about
letting go of the bars. I have almost no direct experience with 'bent
trikes, but I used to work with Rick Horwitz and I very briefly tried
one of his Thunderbolts.

Trikes as a rule have a natural "critical speed" that has more to do
with vehicle dynamics than it does with the rider's fear and
perceptions. Trikes can't lean, so they have a weight shift in turns.
...

Chalo




On reading these posts about instability at speed in trikes or at least
a sense of instability, I began to wonder if there were any trikes that
incorporated wheel lean in their designs. I've noticed on the cutting
edge tech sites many designs for motorized vehicles with wheel lean. Why
not for human powered?

Maybe weight is a factor with the added engineering complexity involved.
On last year's 5 Boro bike tour in New York City a rode along side a
trike for a short distance. I don't know anything about the makes or
designs of trikes but the one I saw reminded me of a formula 1 race car.
It had independent front suspensions with upper and lower control arms.
Also disk brakes and what looked like a monocoque frame design (or least
the look of one).

With upper and lower control arms it doesn't seem to be much of an
extension to have lean incorporated, whether in a preset manner or under
the control of the rider - say in a steering mechanism that allowed for
a turning motion for turning along with a side-to-side sliding motion to
control lean. Even simpler, in the manner of current autos, the
suspension could be designed to force wheel lean depending of the
downward force on it.

I've also seen rollerbladers with unusual skates. Rather than having
many small wheels vertically mounted the unusual skates had two large
wheels (about 8 to 10 inches in diameter) mounted such that they leaned
from the outside of the foot to meet the ground just at the center of
the foot, though obviously some few inches below. Though this lean seems
opposite to the direction needed for turn stability it seems to test the
endurance of the bearing mechanisms involved in lean.

Sport wheel chairs have used a leaning wheel design for some time. Why
isn't this used with trikes?