Fear of Flying

Hey guys -

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 glad we got some numbers into this discussion. As it
turns out, I'm actually in very close agreement with Jeff
on this issue. Although we've been talking about tadpole
trikes, I think the same concerns apply to all 'bents and
other bikes as well.

If you've ever been on one of those parachute drops at a
thrill ride park, you've probably felt that irrational
fear that comes as you suddenly approach weightlessness
and watch the ground begin accelerating up toward you.
I say 'irrational' fear, because you probably assessed
the risk before you got on that thing and decided the
real danger was pretty minimal.

When I first read Jeff's comment that he "had to ride
the brakes" on downhills, I thought he was talking about
keeping his speed below 15 to 20 MPH, and for most folks
with normal reflexes, eyesight, mental stability and
such, feeling any kind of serious terror at 20 MPH on a
contemporary middle-of-the-road tadpole is probably very
close to that same kind of 'irrational' fear as the
parachute drop.

However, as you get into that 30 to 50 MPH range, any
concern for personal safety you feel is more in the
nature of 'rational' fear. The actual number for any one
person will depend on his riding abilities and his own
priorities, the trail, the weather, and the trike. I
think most current model tadpoles are stable and safe
at 20 MPH, but at 40 MPH there are definite differences,
and issues like frame stiffness, tracking, weight bias,
track width, wheelbase, seat height and steering
sensitivity begin to become very important. At speed,
brakes play a major role for a rider's peace of mind -
some folks feel uncomfortable with the higher lever
pressures of drum brakes; some discs are 'grabby' or
hard to modulate; brake steering makes some riders
very uneasy.

As a cyclist who's spent remarkably little time on any
kind of two-wheeled recumbent, I'm often intrigued at
the conversations of 'bent bikers comparing their
impressions of long wheel-base, short wheel-base and
lowracers, and who feels safest at what speed on which
machine. Trikes are probably a bit different in that
they require almost nothing in the way of operator skill
or training at speeds up to 'casual cruising', and some
riders seem to be lulled into forgetting that as they
push the limits, trikes begin to demand some of the same
skills and heightened attention that it takes to ride a
bike fast.

Tadpoles are very stable and simple to ride at low to
medium speeds, and their braking ability may be the best
available on any 'normal' road vehicle, but at some
point, a trikey is exposed to the same real risks as any
other cyclist. For me, that transition from carefree fun
(in lower case) to gunfighter-eyed, yellow-alert, battle
stations, play racer mentality usually comes somewhere
between about 30 and 40 MPH. But hey, sometimes even a
little rational fear is FUN! (upper case with exclamation
point)

Regards,
Wayne

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 often intrigued at
the conversations of 'bent bikers comparing their
impressions of long wheel-base, short wheel-base and
lowracers, and who feels safest at what speed on which
machine. Trikes are probably a bit different in that
they require almost nothing in the way of operator skill
or training at speeds up to 'casual cruising', and some
riders seem to be lulled into forgetting that as they
push the limits, trikes begin to demand some of the same
skills and heightened attention that it takes to ride a
bike fast.

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.
They also have a natural steering response that is relatively
independent of speed. But as speed increases, the weight shift becomes
more sudden and eventually causes a violent response to even mild
steering inputs, up to and including high-siding the trike. Since the
effect of a harsh weight shift is to jar the rider, and this can result
in unplanned steering inputs, there comes a speed at which every trike
can be considered unstable. The lowest critical speed I have seen so
far was in a Trailmate E-Z Roll Regal adult delta trike, which tried to
buck the rider off starting at about 10mph. This was a result, I
believe, of several factors including extravagant frame flex, high C of
G, narrow track, and the misguided use of a normal bicycle fork offset
on a trike with a slack head angle. A trike will naturally become more
stable as it becomes lower, wider, stiffer, or more resistant to
steering input. That's why tadpole 'bents can be considered "sporty"
while upright deltas never are. However, while a sporty 'bent trike
might have a much higher critical speed than a senior citizen's
neighborhood trike, it still has a point beyond which it can be
considered unstable.

Bikes are different. Their front end steering characteristics cause a
natural self-stabilizing force that increases with speed. This force
causes frame, fork, and wheel flex, however, and thus can result in
shimmy problems as speeds and dynamic forces on the frame rise. But in
a bike and rider combination that does not exhibit shimmy, the ride
becomes steadier as speeds increase-- quite the opposite of what
happens with a trike. I used to have a roughly 1/2 mile downhill
averaging about 8% on my way to work, and with a mild crouch over flat
handlebars I routinely hit a measured 55mph on my upright bike--
without any unsteadiness or handling quirks whatsoever.

'Bent bikes tend to be longer, less triangulated, and smaller-wheeled
than uprights, and most of them suffer from compromised steering
geometry that does not not allow the sort of no-hands riding stability
common to uprights. Thus they will flex more (promoting shimmy) and
exhibit less self-stabilizing than a typical upright bike, and this may
contribute to a lower practical maximum operating speed. So because
'bent bikes are (generally speaking) worse than upright bikes with
regard to stability at speed, 'bent trikes are /more stable/ than
upright trikes, and this makes two- and three-wheeled 'bents comparable
to each other in their sure-footedness at high speed. In contrast,
there is really no comparison between DF bikes and upright trikes in
their handling at speed.

Chalo

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 often intrigued at
the conversations of 'bent bikers comparing their
impressions of long wheel-base, short wheel-base and
lowracers, and who feels safest at what speed on which
machine. Trikes are probably a bit different in that
they require almost nothing in the way of operator skill
or training at speeds up to 'casual cruising', and some
riders seem to be lulled into forgetting that as they
push the limits, trikes begin to demand some of the same
skills and heightened attention that it takes to ride a
bike fast.

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.
They also have a natural steering response that is relatively
independent of speed. But as speed increases, the weight shift becomes
more sudden and eventually causes a violent response to even mild
steering inputs, up to and including high-siding the trike. Since the
effect of a harsh weight shift is to jar the rider, and this can result
in unplanned steering inputs, there comes a speed at which every trike
can be considered unstable. The lowest critical speed I have seen so
far was in a Trailmate E-Z Roll Regal adult delta trike, which tried to
buck the rider off starting at about 10mph. This was a result, I
believe, of several factors including extravagant frame flex, high C of
G, narrow track, and the misguided use of a normal bicycle fork offset
on a trike with a slack head angle. A trike will naturally become more
stable as it becomes lower, wider, stiffer, or more resistant to
steering input. That's why tadpole 'bents can be considered "sporty"
while upright deltas never are. However, while a sporty 'bent trike
might have a much higher critical speed than a senior citizen's
neighborhood trike, it still has a point beyond which it can be
considered unstable.

Bikes are different. Their front end steering characteristics cause a
natural self-stabilizing force that increases with speed. This force
causes frame, fork, and wheel flex, however, and thus can result in
shimmy problems as speeds and dynamic forces on the frame rise. But in
a bike and rider combination that does not exhibit shimmy, the ride
becomes steadier as speeds increase-- quite the opposite of what
happens with a trike. I used to have a roughly 1/2 mile downhill
averaging about 8% on my way to work, and with a mild crouch over flat
handlebars I routinely hit a measured 55mph on my upright bike--
without any unsteadiness or handling quirks whatsoever.

'Bent bikes tend to be longer, less triangulated, and smaller-wheeled
than uprights, and most of them suffer from compromised steering
geometry that does not not allow the sort of no-hands riding stability
common to uprights. Thus they will flex more (promoting shimmy) and
exhibit less self-stabilizing than a typical upright bike, and this may
contribute to a lower practical maximum operating speed. So because
'bent bikes are (generally speaking) worse than upright bikes with
regard to stability at speed, 'bent trikes are /more stable/ than
upright trikes, and this makes two- and three-wheeled 'bents comparable
to each other in their sure-footedness at high speed. In contrast,
there is really no comparison between DF bikes and upright trikes in
their handling at speed.

Chalo

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?

In article ePbuh.19361$pb7.13011@trndny09, lid
says...

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?

It /has/ been tried, but the additional weight and complexity were
usually deemed not to be worth it. The Tripendo, for example, was a
German all-carbon leaning trike weighing about half as much again as my
steel Trice.

And hanging out of the seat on a tight corner is part of the fun

--
Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
Trike Vmax 86 km/h; need bigger hill

Dave Larrington wrote:
In article ePbuh.19361$pb7.13011@trndny09, lid
says...


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?


It /has/ been tried, but the additional weight and complexity were
usually deemed not to be worth it. The Tripendo, for example, was a
German all-carbon leaning trike weighing about half as much again as my
steel Trice.

And hanging out of the seat on a tight corner is part of the fun


Thanks for the link. That may be the trike that I saw though I can't be
sure. I only rode along side for about a minute with my concentration on
the front suspension. With a rider seated I couldn't see the futuristic
seat. The wheels were spoked. The monocoque was similar though white or
light gray with a distinctly apparent weave pattern - probably fiber
glass. Though I noticed the double wishbone suspension I didn't think of
it as a leaning trike. It was a flat straight away though so there was
no basis to see lean.

I was looking at some of the linked trikes from this page -
http://home.mindspring.com/~kb7mxu/trikes2.htm

... and saw some other leaning designs.

This one seems to have been dropped since there's only a picture at the
site.
http://home.mindspring.com/~kb7mxu/images/berg.jpg

This one is in development.
http://www.kerrelcycles.com/index.html

The Tripendo is also on the link page.
http://www.tripendo.com/EDEFAULT.htm

As for wheels that permanently lean in the style of sport wheel chairs,
I'd guess that steering and propulsion would have to be via the third
wheel or fairly complex.

MkTm Wrote:
Jeff Grippe wrote:
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. ... Even simpler, in the
manner of current autos, the suspension could be designed to force
wheel lean depending of the downward force on it. Don't understand your auto reference. Car suspension design strive to
achieve and maintain a neutral or slight negative camber through all
driving conditions. Suspension travel and body roll makes this quite
challenging. For a car wheel with its basically rectangular tyre
profile and laterally strong rims there is nothing to be gained from
increasing this angle.
MkTm Wrote:
Jeff Grippe wrote:
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.
But they have their own reason for going that way. The sworn enemy of
recreational inline skating is poor road surfaces, and bigger wheels
helps reduce the amount of vibration generated by smaller wheels. Big
wheels w/o the angle forces you either to build very high skates, or to
stretch the wheelbase until the foot will fit between the wheels.
Besides the unwanted length the stretched 2-point wheelbase also messes
up cornering ability.
MkTm Wrote:
Jeff Grippe wrote:
Sport wheel chairs have used a leaning wheel design for some time. Why
isn't this used with trikes?

It's either done to increase track width, or to prevent wheels from
buckling when cornering, or both.
A DF or 2-wheeled 'bent lean in curves, so they can get by with using
wheels with limited lateral stability. A sport wheel chair can't lean,
so a pre-loaded configuration reduces wheel loads when cornering.

Smaller wheels, like those often found on a trike, can take higher
lateral loads, and the track width of the trike isn't limited to
operator's reach.
I also suspect that steering response would be decidedly odd it you
tried steering with a significantly leaning wheel.


--
dabac

Well having a tadpole trike (Catrike Road) and having crashed it within a
month of getting it let me chime in with some observations. The only
stability problems I've encountered are the "brake steer" effect of side to
side brakes. If one is not aware of the degree of the effect the resulst can
be an oscillating descent which causes one to stiffen up even more
compounding the problem. I've had the trike up to 58kph on relatively flat
terrain with absolutely no problems. I've had the trike up to 76kph down a
curvy descent with no problems IF I stay relaxed. The moment I begin to
tense up (ie Fear), is when instability shows up. I've had many
configurations of DF bikes, hybrids, top-end rigid MTB's and pretty good
road bikes. I've been "on the ground" with all of them too. But I have to
say for high speed cornering, DF's are best, except when you hit some junk
(gravel, RR Xings etc). At least on a trike some junk won't put you down.
And besides, at least my head isn't 7' off the ground. Falls on a DB are
usually sliding road rashers or "dive for the pavement" acrobatics. I stil
feel much safer on my bent trike

Grolsch


"Jeff Grippe" wrote in message
...
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 often intrigued at
the conversations of 'bent bikers comparing their
impressions of long wheel-base, short wheel-base and
lowracers, and who feels safest at what speed on which
machine. Trikes are probably a bit different in that
they require almost nothing in the way of operator skill
or training at speeds up to 'casual cruising', and some
riders seem to be lulled into forgetting that as they
push the limits, trikes begin to demand some of the same
skills and heightened attention that it takes to ride a
bike fast.

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.
They also have a natural steering response that is relatively
independent of speed. But as speed increases, the weight shift becomes
more sudden and eventually causes a violent response to even mild
steering inputs, up to and including high-siding the trike. Since the
effect of a harsh weight shift is to jar the rider, and this can result
in unplanned steering inputs, there comes a speed at which every trike
can be considered unstable. The lowest critical speed I have seen so
far was in a Trailmate E-Z Roll Regal adult delta trike, which tried to
buck the rider off starting at about 10mph. This was a result, I
believe, of several factors including extravagant frame flex, high C of
G, narrow track, and the misguided use of a normal bicycle fork offset
on a trike with a slack head angle. A trike will naturally become more
stable as it becomes lower, wider, stiffer, or more resistant to
steering input. That's why tadpole 'bents can be considered "sporty"
while upright deltas never are. However, while a sporty 'bent trike
might have a much higher critical speed than a senior citizen's
neighborhood trike, it still has a point beyond which it can be
considered unstable.

Bikes are different. Their front end steering characteristics cause a
natural self-stabilizing force that increases with speed. This force
causes frame, fork, and wheel flex, however, and thus can result in
shimmy problems as speeds and dynamic forces on the frame rise. But in
a bike and rider combination that does not exhibit shimmy, the ride
becomes steadier as speeds increase-- quite the opposite of what
happens with a trike. I used to have a roughly 1/2 mile downhill
averaging about 8% on my way to work, and with a mild crouch over flat
handlebars I routinely hit a measured 55mph on my upright bike--
without any unsteadiness or handling quirks whatsoever.

'Bent bikes tend to be longer, less triangulated, and smaller-wheeled
than uprights, and most of them suffer from compromised steering
geometry that does not not allow the sort of no-hands riding stability
common to uprights. Thus they will flex more (promoting shimmy) and
exhibit less self-stabilizing than a typical upright bike, and this may
contribute to a lower practical maximum operating speed. So because
'bent bikes are (generally speaking) worse than upright bikes with
regard to stability at speed, 'bent trikes are /more stable/ than
upright trikes, and this makes two- and three-wheeled 'bents comparable
to each other in their sure-footedness at high speed. In contrast,
there is really no comparison between DF bikes and upright trikes in
their handling at speed.

Chalo

Jeff Grippe wrote:

The Infinity, which
was the oldest and lowest end of the bikes I've owned was my favorite.

I test rode an Infinity back in the late '80s. It wasn't my bag, but
it was worlds easier to tolerate than the BikeE I spent a long weekend
with in 2001.

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.

Quads must either have full suspension or a frame that articulates in
the middle, allowing the front end to tilt one way and the rear axle to
tilt another way. This adds greatly to the weight and expense of a
quad. In most states they don't have a right to the road either. And
they lose a lot of energy to wheel scrub in corners, substanttially
more than trikes. But aside from all that, they can corner better for
any given width, length, height, and weight distribution than a trike.


Chalo

Hey folks -

Who says we can't have interesting on-topic discussions
here at ARBR? For starters, I recognize that many
cyclists may feel more at ease on a two-wheeler at high
speed than on a trike. I think one of the reasons for
this is that it's a fairly simple learning process for
us to make controlling a bike with subtle leaning and
weight shifts pretty much instinctive, and most of us
learned it long ago when our brains were young and wide
open. Another reason is that unlike a trikey at low to
moderate speeds, a biker is ALWAYS required to
continuously interact with his cycle, even though it is
a largely subconscious process. There's not much in the
way of a transition from riding a bike at 12 MPH to
zipping along at three times that speed.

Chalo wrote:

Trikes as a rule have a natural "critical speed"... as
speed increases, the weight shift becomes more sudden
and eventually causes a violent response to even mild
steering inputs, up to and including high-siding the
trike.

While I can appreciate most of chalo's comments, this
bit seems to me to be what a logics professor might call
'A giant leap from a fallacious assumption to an
erroneous conclusion'. ;-) What exactly is this strange
"weight shift" and why would it become "more sudden"?
A well-designed stiff tadpole with an experienced, even
modestly talented rider doesn't go through some kind of
radical transition (like an aircraft at Mach One) so
that it begins to provide a "violent response" to his
control inputs.

The front end geometry of a tadpole is pretty much the
same as an automobile's, and as far as I know, there's
no such thing as a "critical speed". Of course, with
good lateral traction a driver can roll a Miata, just
as a rider can roll a trike. Speed plays a big role in
rollover susceptibility, and tadpoles have comparatively
sensitive steering, meaning: the front wheels turn much
farther for a one-inch movement of your hands on the
bar than on an auto. At higher speeds, small steering
inputs cause higher lateral acceleration than at lower
speeds, and of course it takes a smaller jerk of the
bars to flip a trike at 50 MPH than it does at 5 MPH.

One simple fact of cycle dynamics, however, is that a
trike is inherently very stable in the roll axis at
any speed, even parked. A bike, meaning a vehicle with
two tires on the same lateral axis, has no - ZERO! -
long-term roll stability. It wouldn't be a very serious
engineering challenge to implement a stone simple
servo-controlled single-axis automated steering system
for a trike, using an airplane type gyro, so that it
would roll down a hill in a straight line. I won't stay
up waiting for someone to do that with a bike...

The biggest single difference that I see between bikes
and trikes is that anyone riding a two-wheeler has to
constantly make minor steering and/or weight shift
corrections to keep the bike upright AT ANY SPEED, and
the process of making those continuous compensations
becomes almost subconscious for him. The process is made
a bit more appropriate to normal human aptitudes by the
short-term stability provided by the precession effect
of the wheels and the rounded profile of bike tires.
But on a trike, at low and medium speeds, there is
absolutely no need for the rider to do anything but make
minor steering corrections. When the trike begins going
fast enough to make it more of a challenge to control
its direction with its sensitive steering, compensating
and correcting for stiction, linkage slack and
hysteresis, it begins to demand a lot more in the way of
attention, precision and good reflexes. If that seems to
set some kind of "critical speed" for the trike, or to
give it a Jekyll-Hyde nature, it's probably a good idea
to remember that the real difference from a bike is that
a bike is always in the Hyde mode.

I've used the analogy before, but if you put a big
long-stroke steam engine pumping the pedals on a trike,
and send it off down the road, it may go in the wrong
direction, and it may waggle back and forth, but... if
you do the same thing on a bike, it most likely won't
make it out of shrapnel range before it falls over and
explodes!

Regards,
Wayne