Riding no hands, something's wrong......
Adrian
27 x 1-1/8 to 700 x 22mm. Nothing else have changed. With the new
thinner wheels, the bike is much harder to ride no hands, harder to
balance. What happened?
Adrian
Paul Southworth
Both sets of wheels dished identically, and frame/fork/dropouts
are straight, and wheels installed perfectly straight? Usually
somewhere along the line there's an error. Personally I've never
noticed a difference between wider vs. thinner tires and ease of
no-hands riding, so I am skeptical about the rest of the details.
--Paul
Ron Hardin
If it simply requires being cocked to one side or the other to go
straight, try reangling the wheel side to side as much as possible
without binding on the frame or dragging a brake.
No-handed riding though depends too on the mass of the rim and wheel
to produce an initial countersteer (if you want to turn left, you
cock the bike left, and that results immediately in the front wheel
going right because there's more rim/wheel ahead of the head tube line
and it lags behind the frame cocking motion; that initial turn right
puts the bike off balance to the left and then the front wheel tracks
into a left turn. Unturning is the same, you cock the frame back
upright, and the front wheel initially swings left putting the wheels
under the cg and then tracks straight. This counter-steer is actually
counter to gyroscopic action).
SO, if it's that the countersteer is now a smaller effect, either
you have to learn to live with it, or you can try putting a small weight
on a stick sticking forward from the line of the head-tube, either
on aerobars or just temporarily screw a stick on, to see if that's
what's going on.
--
Ron Hardin
rhha...@mindspring.com
On the internet, nobody knows you're a jerk.
jobst....@stanfordalumni.org
Your wheels are lighter and have less gyroscopic effect, the effect
than makes riding no-hands possible. Fill the tires with water and
all will be great again. (that's done by completely deflating the
tire and filling the hand pump cylinder with water before each stroke)
On the other hand, the difference can't be much from my experience
with various weight wheels. The heavier wheels are easier to ride
no-hands but that's not a problem the way I see it.
Jobst Brandt <jobst....@stanfordalumni.org>
Ron Hardin
> under the cg and then tracks straight. This counter-steer is actually
> counter to gyroscopic action).
That's the reason, by the way, in case anybody wondered, why high
speed makes no-handed riding more difficult. The gyroscopic action
(cock frame left turns front wheel left) builds in importance over
the inertial lag (cock frame left turns front wheel right) that
no-handed steering needs.
The bike remains stable but is difficult to steer.
Ron Hardin
> Your wheels are lighter and have less gyroscopic effect, the effect
> than makes riding no-hands possible. Fill the tires with water and
> all will be great again. (that's done by completely deflating the
> tire and filling the hand pump cylinder with water before each stroke)
> On the other hand, the difference can't be much from my experience
> with various weight wheels. The heavier wheels are easier to ride
> no-hands but that's not a problem the way I see it.
The opposite is true! Gyroscopic effects defeat no-handed steering
control, though not balance.
You need do need the wheel mass, but not for that reason.
Walk your bike quickly and cock the frame quickly left and watch what the
front wheel does. It goes right! then left.
More of the front wheel mass is ahead of the head tube line, and that
dead mass is left behind temporarily when the frame goes left.
Thus it produces the necessary right counter-steer for a left turn.
Gyroscopic effects would turn the front wheel left initially, not right.
jobst....@stanfordalumni.org
> SO, if it's that the countersteer is now a smaller effect, either
> you have to learn to live with it, or you can try putting a small
> weight on a stick sticking forward from the line of the head-tube,
> either on aerobars or just temporarily screw a stick on, to see if
> that's what's going on.
Not so. A weight out front will not make steering any easier. The
gyro response is immediate and rapid whereas gravitational response of
a weight attached to the bars has inertia and much delay. Just try
riding no-hands and move your knee from side to side quickly. A
weight will counter that steering effect.
And let's call it steering effect rather than "countersteer".
> On the internet, nobody knows you're a jerk.
Don't you believe it. Jerks expose themselves regularly.
Jobst Brandt <jobst....@stanfordalumni.org>
Ron Hardin
> > SO, if it's that the countersteer is now a smaller effect, either
> > you have to learn to live with it, or you can try putting a small
> > weight on a stick sticking forward from the line of the head-tube,
> > either on aerobars or just temporarily screw a stick on, to see if
> > that's what's going on.
>
> Not so. A weight out front will not make steering any easier. The
> gyro response is immediate and rapid whereas gravitational response of
> a weight attached to the bars has inertia and much delay. Just try
> riding no-hands and move your knee from side to side quickly. A
> weight will counter that steering effect.
>
> And let's call it steering effect rather than "countersteer".
I love counterintuitive things that turn out to be at the bottom
of it all.
The gyroscopic effect you want goes the other way, and if you're
going fast enough in fact prevents you from steering by rising
in influence and preventing a countersteer.
Countersteer is the correct term, an initial turn to the right
in order to start a turn to the left.
--
Ron Hardin
rhha...@mindspring.com
jobst....@stanfordalumni.org
>> Your wheels are lighter and have less gyroscopic effect, the effect
>> than makes riding no-hands possible. Fill the tires with water and
>> all will be great again. (that's done by completely deflating the
>> tire and filling the hand pump cylinder with water before each
>> stroke) On the other hand, the difference can't be much from my
>> experience with various weight wheels. The heavier wheels are
>> easier to ride no-hands but that's not a problem the way I see it.
> The opposite is true! Gyroscopic effects defeat no-handed steering
> control, though not balance.
That is incorrect. No-hands riding is done by use of the gyroscopic
effect in the wheel.
> You need do need the wheel mass, but not for that reason.
I think you should do some experimenting with controls so that you
can assess the effects. As wheel weight approaches zero the
gyroscopic effect also vanishes and it is this effect that enables
people to ride no-hands.
> Walk your bike quickly and cock the frame quickly left and watch what the
> front wheel does. It goes right! then left.
It steers the way I want it to go. I suppose you don't push your
bicycle by holding on to the saddle as is common. In that mode, the
gyroscopic effect is used and it fails as speed goes to zero.
> More of the front wheel mass is ahead of the head tube line, and that
> dead mass is left behind temporarily when the frame goes left.
> Thus it produces the necessary right counter-steer for a left turn.
You are mis-attributing the steering effects. If you do this while
riding, you will notice that steering motions can be made much faster
than inertia and weight of the wheel alone can respond. Riding
no-hands, sharp choppy corrections can be made that are not possible
with a pendulum effect. You can prove this by leaning a standing
bicycle to one side and watch the response.
> Gyroscopic effects would turn the front wheel left initially, not right.
I get the impression that you do not ride no-hands at speed or you
wouldn't say this.
> On the internet, nobody knows you're a jerk.
You are treading on thin ice. You might drop this from your sig
before you disprove it.
Jobst Brandt <jobst....@stanfordalumni.org>
Ron Hardin
> > Gyroscopic effects would turn the front wheel left initially, not right.
>
> I get the impression that you do not ride no-hands at speed or you
> wouldn't say this.
Well, we can start with this. Take your right hand and curl the fingers
in the direction that the front wheel is turning. Your thumb will be
to the left. That's the angular momentum vector, horizontal straight left.
Cocking the frame to the left exerts a torque (curl fingers again) with
thumb straight back.
Adding thumb back to thumb left gives thumb left and a little back.
That corresponds to (look at curl of fingers) the new angular momentum
vector with the wheel turned left.
That's the gyroscopic effect. Cock the frame left and the wheel turns left.
(You can get this without the mumbo jumbo by observing that cocking the
frame left accelerates the top of the wheel left, and by the time the top
of the wheel gets to the front this has become a displacement to the left,
and thus a turning left of the front wheel.)
Okay so far?
--
Ron Hardin
rhha...@mindspring.com
jobst....@stanfordalumni.org
>>> SO, if it's that the countersteer is now a smaller effect, either
>>> you have to learn to live with it, or you can try putting a small
>>> weight on a stick sticking forward from the line of the head-tube,
>>> either on aerobars or just temporarily screw a stick on, to see if
>>> that's what's going on.
>> Not so. A weight out front will not make steering any easier. The
>> gyro response is immediate and rapid whereas gravitational response
>> of a weight attached to the bars has inertia and much delay. Just
>> try riding no-hands and move your knee from side to side quickly.
>> A weight will counter that steering effect.
>> And let's call it steering effect rather than "countersteer".
> I love counterintuitive things that turn out to be at the bottom
> of it all.
> The gyroscopic effect you want goes the other way, and if you're
> going fast enough in fact prevents you from steering by rising
> in influence and preventing a countersteer.
You dodge the issue. I can ride a rapis slalom with the gyroscopic
effect, making streering motions that are many times fastrer than the
ones you envision arising from a weight extrnded forward from the
bars.
> Countersteer is the correct term, an initial turn to the right
> in order to start a turn to the left.
It's all steering and what you do with it is the same. That
subject is included in the FAQ item:
http://draco.acs.uci.edu/rbfaq/FAQ/168.html
* Countersteer
* Countersteer is a popular subject for people who belatedly discover
* or rediscover how to balance. What is not apparent, is that two
* wheeled vehicles can be controlled ONLY by countersteer, there is no
* other way. Unlike a car, a bicycle cannot be diverted from a
* straight path by turning the wheel to one side. The bicycle must
* first be leaned in that direction by steering the opposite way.
* This is the means by which a broomstick is balanced on the palm of
* the hand or a bicycle on the road. The point of support is moved
* plumb beneath the mass with combined forces of gravity and cornering
* by steering, first counter and then with the curve. It is so self
* evident that runners never mention it, although football,
* basketball, and ice hockey players do it conspicuously.
Jobst Brandt <jobst....@stanfordalumni.org>
jobst....@stanfordalumni.org
>>> SO, if it's that the countersteer is now a smaller effect, either
>>> you have to learn to live with it, or you can try putting a small
>>> weight on a stick sticking forward from the line of the head-tube,
>>> either on aerobars or just temporarily screw a stick on, to see if
>>> that's what's going on.
>> Not so. A weight out front will not make steering any easier. The
>> gyro response is immediate and rapid whereas gravitational response
>> of a weight attached to the bars has inertia and much delay. Just
>> try riding no-hands and move your knee from side to side quickly.
>> A weight will counter that steering effect.
>> And let's call it steering effect rather than "countersteer".
> I love counterintuitive things that turn out to be at the bottom
> of it all.
> The gyroscopic effect you want goes the other way, and if you're
> going fast enough in fact prevents you from steering by rising
> in influence and preventing a countersteer.
You dodge the issue. I can ride a rapid slalom with the gyroscopic
effect, making steering motions that are many times faster than the
ones you envision arising from a weight extended forward from the
bars.
> Countersteer is the correct term, an initial turn to the right
> in order to start a turn to the left.
It's all steering and what you do with it is the same. That
Dave Blake
>> The opposite is true! Gyroscopic effects defeat no-handed
>> steering control, though not balance.
>
> That is incorrect. No-hands riding is done by use of the
> gyroscopic effect in the wheel.
>
> > You need do need the wheel mass, but not for that reason.
>
> I think you should do some experimenting with controls so
> that you can assess the effects. As wheel weight approaches
> zero the gyroscopic effect also vanishes and it is this
> effect that enables people to ride no-hands.
I can ride a ski-bike no handed, and it has no front wheel and
thus no gyroscopic effect.
But it has trail.
--
Dave Blake
dbl...@phy.ucsf.edu
Dave Blake
> Adrian who? writes:
>
> > I changed (and trued) the wheels/tires on my road bike last week,
> > from 27 x 1-1/8 to 700 x 22mm. Nothing else have changed. With the
> > new thinner wheels, the bike is much harder to ride no hands, harder
> > to balance. What happened?
>
> Your wheels are lighter and have less gyroscopic effect, the effect
> than makes riding no-hands possible. Fill the tires with water and
> all will be great again.
So you think his reduction in trail is irrelevant, and it all
comes down to gyroscopes, countersteer, and trolls ?
You used a smaller wheel and tire. This reduces trail. Trail is
the distance between the projection of the head tube axis onto
the ground and the contact patch. The contact patch always
trails the projection of the steering axis.
Just picture the casters on a grocery store cart. They have an
offset from the steering axis to generate trail, and that
stabilizes them with a constant direction of motion.
You used a smaller wheel. This in itself makes the steering
angle steeper (about a degree in your case, I think), and
reduces trail.
Reductions in trail are quite noticeable. Without front wheel
trail, no hands riding for any substantial distance is
impossible, because the front steering is unstable. I think you
will have to learn to live with it, or get a fork made to lift
your front end higher (thus changing the steerer angle back and
increasing trail).
--
Dave Blake
dbl...@phy.ucsf.edu
Peter Cole
"Dave Blake" <dbl...@popper.ucsf.edu> wrote in message
news:slrn9rp7ec...@popper.ucsf.edu...
Marcus Coles
once car drivers never figured out.
Would the minor change in the location of the contact patch of the
front tire relative to the steering axis with the reduction in rolling
diameter be a contributing factor or negligable in this circumstance?
Marcus
Peter Cole
>
> So you think his reduction in trail is irrelevant, and it all
> comes down to gyroscopes, countersteer, and trolls ?
>
> You used a smaller wheel and tire. This reduces trail. Trail is
> the distance between the projection of the head tube axis onto
> the ground and the contact patch. The contact patch always
> trails the projection of the steering axis.
>
> Just picture the casters on a grocery store cart. They have an
> offset from the steering axis to generate trail, and that
> stabilizes them with a constant direction of motion.
>
> You used a smaller wheel. This in itself makes the steering
> angle steeper (about a degree in your case, I think), and
> reduces trail.
>
> Reductions in trail are quite noticeable. Without front wheel
> trail, no hands riding for any substantial distance is
> impossible, because the front steering is unstable. I think you
> will have to learn to live with it, or get a fork made to lift
> your front end higher (thus changing the steerer angle back and
> increasing trail).
Lowering trail makes the steering more "twitchy" (has less centering
tendency), which makes controlled no-hands harder in that the response time
of the steering might become faster than the rider's sensation/control
response time (reaction speed). It still is driven by gyroscopic forces.
Riding no-hands becomes impossible at very low speeds.
jobst....@stanfordalumni.org
>>> I changed (and trued) the wheels/tires on my road bike last week,
>>> from 27 x 1-1/8 to 700 x 22mm. Nothing else have changed. With
>>> the new thinner wheels, the bike is much harder to ride no hands,
>>> harder to balance. What happened?
>> Your wheels are lighter and have less gyroscopic effect, the effect
>> than makes riding no-hands possible. Fill the tires with water and
>> all will be great again.
> So you think his reduction in trail is irrelevant, and it all comes
> down to gyroscopes, countersteer, and trolls ?
The change in trail is too small to make a difference. I don't know
what the difference in radius is between a 700c and 27" tire but
assuming it is about 6mm at 17 degrees that makes less than 2mm change
in trail. I don't think that makes a noticeable difference.
> You used a smaller wheel and tire. This reduces trail. Trail is
> the distance between the projection of the head tube axis onto
> the ground and the contact patch. The contact patch always
> trails the projection of the steering axis.
> Just picture the casters on a grocery store cart. They have an
> offset from the steering axis to generate trail, and that
> stabilizes them with a constant direction of motion.
Their ratio of wheel diameter to trail is more than 10x of bicycle
trail. I don't think that is a good analogy.
> You used a smaller wheel. This in itself makes the steering
> angle steeper (about a degree in your case, I think), and
> reduces trail.
The steering angle change is the (wheel radius change/wheelbase) or
piffles to be accurate.
> Reductions in trail are quite noticeable. Without front wheel
> trail, no hands riding for any substantial distance is
> impossible, because the front steering is unstable. I think you
> will have to learn to live with it, or get a fork made to lift
> your front end higher (thus changing the steerer angle back and
> increasing trail).
Stunt bicycles have no trail and a vertical steer tube and are ridden
to great success by experts in the business. If you get the chance
see the movie "Joe E Brown at the Six Day Races", a must for all
bikies... a classic.
http://www.hollywood.com/celebs/detail/celeb/199367
Don't miss it!
Jobst Brandt <jobst....@stanfordalumni.org>
jobst....@stanfordalumni.org
>>> The opposite is true! Gyroscopic effects defeat no-handed
>>> steering control, though not balance.
>> That is incorrect. No-hands riding is done by use of the
>> gyroscopic effect in the wheel.
>>> You need do need the wheel mass, but not for that reason.
>> I think you should do some experimenting with controls so that you
>> can assess the effects. As wheel weight approaches zero the
>> gyroscopic effect also vanishes and it is this effect that enables
>> people to ride no-hands.
> I can ride a ski-bike no handed, and it has no front wheel and
> thus no gyroscopic effect.
> But it has trail.
It steers much like the effect of a skate board or roller skate which
is neither gyroscopic or pendulum torque, but forced alignment.
Jobst Brandt <jobst....@stanfordalumni.org>
jobst....@stanfordalumni.org
>>> I changed (and trued) the wheels/tires on my road bike last week,
>>> from 27 x 1-1/8 to 700 x 22mm. Nothing else have changed. With
>>> the new thinner wheels, the bike is much harder to ride no hands,
>>> harder to balance. What happened?
>> Your wheels are lighter and have less gyroscopic effect, the effect
>> than makes riding no-hands possible. Fill the tires with water and
>> all will be great again.
> So you think his reduction in trail is irrelevant, and it all comes
> down to gyroscopes, countersteer, and trolls ?
The change in trail is too small to make a difference. I don't know
what the difference in radius is between a 700c and 27" tire but
assuming it is about 6mm at 17 degrees that makes less than 2mm change
in trail. I don't think that makes a noticeable difference.
> You used a smaller wheel and tire. This reduces trail. Trail is
> the distance between the projection of the head tube axis onto
> the ground and the contact patch. The contact patch always
> trails the projection of the steering axis.
> Just picture the casters on a grocery store cart. They have an
> offset from the steering axis to generate trail, and that
> stabilizes them with a constant direction of motion.
Their ratio of wheel diameter to trail is more than 10x of bicycle
trail. I don't think that is a good analogy.
> You used a smaller wheel. This in itself makes the steering
> angle steeper (about a degree in your case, I think), and
> reduces trail.
The steering angle change is ATAN(wheel radius change/wheelbase) or
piffles to be accurate.
> Reductions in trail are quite noticeable. Without front wheel
> trail, no hands riding for any substantial distance is
> impossible, because the front steering is unstable. I think you
> will have to learn to live with it, or get a fork made to lift
> your front end higher (thus changing the steerer angle back and
> increasing trail).
Stunt bicycles have no trail and a vertical steer tube and are ridden
Ron Hardin
> You dodge the issue. I can ride a rapid slalom with the gyroscopic
> effect, making steering motions that are many times faster than the
> ones you envision arising from a weight extended forward from the
> bars.
Do you agree that gyroscopic effects turn the wheel left when you
cock the frame left?
That's important to establish. Because you'll readily see if you
try it that riding slowly no-handed, if you turn left by cocking
the frame left, the wheel swings right first. If however you think
that cocking the frame left gyroscopically turns the wheel right,
then I have to use a different argument to convince you that it
doesn't. I'm not sure where to begin, in other words.
What the gyroscopic effect does (the reason it's harder and harder
to ride slowly) is prevent the wheel from overshooting. If you're
going too slowly for your skill level, the wheel overshoots and you
lose control. This doesn't happen at reasonable speed because the
gyroscopic effect prevents it by stabilizing the direction. With
increasing practice, you can ride slow and slower no-handed and all
your time will be spent trying to stabilize the direction of the
front wheel.
In addition, the gyroscopic effect balances the bicycle. If the
frame starts falling left, it turns left and remains in a turn to
balance it out. It finally crashes by getting into too sharp a turn
in the end, but not by falling over.
The rider's contribution is steering that stable mechanism. He does it
by countersteering to cause falls in the direction he wants. This
becomes more and more difficult the faster you go (above a certain
minimum) because gyroscopic action eventually overcomes countersteer.
As to speed of reaction, inertia is in fact faster than gyroscopic
action. It's the frame that moves, not the front of the wheel.
All the front of the wheel has to do is stay put, and it does that
infinitely fast.
Ron Hardin
> It's all steering and what you do with it is the same. That
> subject is included in the FAQ item:
Try putting a weight aft of the head tube axis so that the front
wheel balances out, turning neither left nor right when you lift
it up at any angle. So that there's no inertia effect, in other words,
when you cock the frame left.
Then try riding no-handed.
Dave Blake
> dbl...@phy.ucsf.edu wrote:
>> So you think his reduction in trail is irrelevant, and it all
>> comes down to gyroscopes, countersteer, and trolls ?
>
> The change in trail is too small to make a difference. I
> don't know what the difference in radius is between a 700c
> and 27" tire but assuming it is about 6mm at 17 degrees that
> makes less than 2mm change in trail. I don't think that
> makes a noticeable difference.
He went from a 1 1/8" 27 inch tire to a 700C 22 mm tire.
The tires alone give a difference of about 10 mm.
The 27 inch to 700C adds a few more mm. But really, he went
from a fairly wide 27 inch tire to a really narrow tire.
These effects are noticeable enough that some people use light
very wide knobby tires to stabilize steering.
>> Reductions in trail are quite noticeable. Without front wheel
>> trail, no hands riding for any substantial distance is
>> impossible, because the front steering is unstable. I think
>> you will have to learn to live with it, or get a fork made to
>> lift your front end higher (thus changing the steerer angle
>> back and increasing trail).
>
> Stunt bicycles have no trail and a vertical steer tube and
> are ridden to great success by experts in the business.
I think few people will every learn to ride in a straight line
with no hands on a bike with no trail.
--
Dave Blake
dbl...@phy.ucsf.edu
Marcus Coles
I ran a quick sketch across my screen and made some assumptions
Based on a 73 degree head angle
A 5cm fork bend ..
A change in rolling radius from 34.5 cm to 33.5 cm
The distance of the contact patch behind the steering axis went from
5.75 cm to 5.30 cm
Marcus
jobst....@stanfordalumni.org
>> You dodge the issue. I can ride a rapid slalom with the gyroscopic
>> effect, making steering motions that are many times faster than the
>> ones you envision arising from a weight extended forward from the
>> bars.
> Do you agree that gyroscopic effects turn the wheel left when you
> cock the frame left?
Only if you do it at low speeds where the gyroscopic effect is close
to zero, otherwise it steers to the side you lean the bicycle,
especially if it has a vertical fork with no trail. That is why I
suggest you watch Joe E Brown ride bike.
> That's important to establish. Because you'll readily see if you
> try it that riding slowly no-handed, if you turn left by cocking the
> frame left, the wheel swings right first. If however you think that
> cocking the frame left gyroscopically turns the wheel right, then I
> have to use a different argument to convince you that it doesn't.
> I'm not sure where to begin, in other words.
Please! I have a bicycle, I ride it and I have pushed it often with
hand on saddle as is common when walking a bicycle.
> What the gyroscopic effect does (the reason it's harder and harder
> to ride slowly) is prevent the wheel from overshooting. If you're
> going too slowly for your skill level, the wheel overshoots and you
> lose control. This doesn't happen at reasonable speed because the
> gyroscopic effect prevents it by stabilizing the direction. With
> increasing practice, you can ride slow and slower no-handed and all
> your time will be spent trying to stabilize the direction of the
> front wheel.
I think you have the cart before the horse. The opposite steering
motion is an inertial effect that is fixed for a given tilt rate while
gyroscopic force varies with the square of speed. At higher speeds,
inertial effect is completely overshadowed by gyroscopic effect in
contrast to lower speeds where gyroscopic steer collapses and only an
uncontrollable inertial element remains.
> In addition, the gyroscopic effect balances the bicycle. If the
> frame starts falling left, it turns left and remains in a turn to
> balance it out. It finally crashes by getting into too sharp a turn
> in the end, but not by falling over.
It does not unless you are talking about a riderless bicycle.
> The rider's contribution is steering that stable mechanism. He does it
> by countersteering to cause falls in the direction he wants. This
> becomes more and more difficult the faster you go (above a certain
> minimum) because gyroscopic action eventually overcomes countersteer.
As I said, that's the way we walk or run so what's new about that
other than that most people cannot recognize that it is basic
balancing whether ion a bicycle or ice skates.
> As to speed of reaction, inertia is in fact faster than gyroscopic
> action. It's the frame that moves, not the front of the wheel. All
> the front of the wheel has to do is stay put, and it does that
> infinitely fast.
Not at all, because it is too small at higher speeds, the speeds of
interest in bicycle riding to have any effect.
> On the internet, nobody knows you're a jerk.
You are getting closer to existence proof.
Jobst Brandt <jobst....@stanfordalumni.org>
jobst....@stanfordalumni.org
>> It's all steering and what you do with it is the same. That
>> subject is included in the FAQ item:
> Try putting a weight aft of the head tube axis so that the front
> wheel balances out, turning neither left nor right when you lift it
> up at any angle. So that there's no inertia effect, in other words,
> when you cock the frame left.
> Then try riding no-handed.
I capitulate. I haven't the facility to test that and I can only
guess what the result will be. Maybe you can fill us in on what you
discovered when doing the experiment. I'm interested because I have
easily ridden a bicycle no-hands without handlebars and stem (no
weight out front other than the offset of the wheel in the fork).
Jobst Brandt <jobst....@stanfordalumni.org>
Ron Hardin
> > Do you agree that gyroscopic effects turn the wheel left when you
> > cock the frame left?
>
> Only if you do it at low speeds where the gyroscopic effect is close
> to zero, otherwise it steers to the side you lean the bicycle,
> especially if it has a vertical fork with no trail. That is why I
> suggest you watch Joe E Brown ride bike.
I am baffled what it is you believe. The gyroscopic effect turns the wheel
left when you cock the frame left. Verify this by lifting the front wheel
off the ground and spinning the wheel and tilting the frame. It's easy.
Use the unattached front wheel and it's even easier to check.
The inertial effect turns the wheel right when you cock the frame left.
This is what makes steering no-handed possible. It's easiest to see
at low speeds, as you say, thus confusing me as to what you're arguing,
since you seem to be taking my side.
My additional observation is that at high speeds, steering no-handed becomes
less and less effective, precisely because the gyroscopic effect increases
and it goes in the wrong direction for steering control. You don't fall over
but you can't steer very well.
The inertial effect is always there (it just subtracts linearly from
the gyroscopic effect) but it becomes less and less effective. You can make
it bigger by putting additional weight ahead of the line of the head tube.
--
Ron Hardin
rhha...@mindspring.com
jobst....@stanfordalumni.org
>>> Do you agree that gyroscopic effects turn the wheel left when you
>>> cock the frame left?
>> Only if you do it at low speeds where the gyroscopic effect is
>> close to zero, otherwise it steers to the side you lean the
>> bicycle, especially if it has a vertical fork with no trail. That
>> is why I suggest you watch Joe E Brown ride bike.
> I am baffled what it is you believe. The gyroscopic effect turns
> the wheel left when you cock the frame left. Verify this by lifting
> the front wheel off the ground and spinning the wheel and tilting
> the frame. It's easy. Use the unattached front wheel and it's even
> easier to check.
> The inertial effect turns the wheel right when you cock the frame
> left. This is what makes steering no-handed possible. It's easiest
> to see at low speeds, as you say, thus confusing me as to what
> you're arguing, since you seem to be taking my side.
I'm saying that the effect you observe is not significant at higher
speeds for the reasons I stated (and you chose not to cite).
> My additional observation is that at high speeds, steering no-handed becomes
> less and less effective, precisely because the gyroscopic effect increases
> and it goes in the wrong direction for steering control. You don't fall over
> but you can't steer very well.
That doesn't hold up because all my highest speeds are done no-hands
when I am tucked in on steep descents and steering around curves on
mountain roads works excellently. I don't do it in maximum lean
curves because steering is asymmetric, into the curve and out of it,
becoming a bit twitchy when tightening the radius.
> The inertial effect is always there (it just subtracts linearly from
> the gyroscopic effect) but it becomes less and less effective. You
> can make it bigger by putting additional weight ahead of the line of
> the head tube.
So? What is the result of the experiment you suggested I do?
Jobst Brandt <jobst....@stanfordalumni.org>
Mark Hickey
>I capitulate. I haven't the facility to test that and I can only
>guess what the result will be. Maybe you can fill us in on what you
>discovered when doing the experiment. I'm interested because I have
>easily ridden a bicycle no-hands without handlebars and stem (no
>weight out front other than the offset of the wheel in the fork).
Jobst, don't give the weight weenies any ideas....
Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
Joshua Putnam
>jobst....@stanfordalumni.org <jobst....@stanfordalumni.org> scribed:
>> Adrian who? writes:
>>
>> > I changed (and trued) the wheels/tires on my road bike last week,
>> > from 27 x 1-1/8 to 700 x 22mm. Nothing else have changed. With the
>> > new thinner wheels, the bike is much harder to ride no hands, harder
>> > to balance. What happened?
>>
>> Your wheels are lighter and have less gyroscopic effect, the effect
>> than makes riding no-hands possible. Fill the tires with water and
>> all will be great again.
>So you think his reduction in trail is irrelevant, and it all
>comes down to gyroscopes, countersteer, and trolls ?
>
>You used a smaller wheel and tire. This reduces trail. Trail is
>the distance between the projection of the head tube axis onto
>the ground and the contact patch. The contact patch always
>trails the projection of the steering axis.
I would certainly agree that this has a noticeable effect on
handling, switching from wide 27" tires to skinny 700c tires is a
significant change in diameter.
>You used a smaller wheel. This in itself makes the steering
>angle steeper (about a degree in your case, I think), and
>reduces trail.
If I read the original posting correctly, he swapped both wheels
for the smaller size, so the steering angle doesn't change, only
the diameter of the wheels.
>Reductions in trail are quite noticeable. Without front wheel
>trail, no hands riding for any substantial distance is
>impossible, because the front steering is unstable. I think you
>will have to learn to live with it, or get a fork made to lift
>your front end higher (thus changing the steerer angle back and
>increasing trail).
If my reading is correct and he changed both wheels, then the
head tube angle is the same as before. The simplest fix would be
big 700c tires. 700x35C is roughly the same diameter as 27x1-1/8
so a high-pressure touring tire might work without too much extra
rolling resistance.
Depending on the existing fork's geometry, he might simply find
one with less rake, restoring the lost trail. Many older bike
shops have buckets of old forks around so a decent 27"-wheel fork
might be cheap and easy to find.
Or, if he wanted to lift the front end, depending on how many
spacers are in his headset stack and what headset he now has, he
might find a taller fork crown race or a bottom cup that sticks
down further below the bottom of the head tube. Either one
raises the front end and slackens the steering angle, though some
riders would have a fit at the slightly-non-level top tube. A
top tube that is very close to level looks to some people like
the builder meant it to be level and goofed, though there's no
particular reason a top tube *needs* to be level.
--
jo...@phred.org is Joshua Putnam
http://www.phred.org/~josh/
Updated Infrared Photography Books List:
http://www.phred.org/~josh/photo/irbooks.html
Joshua Putnam
>The change in trail is too small to make a difference. I don't know
>what the difference in radius is between a 700c and 27" tire but
>assuming it is about 6mm at 17 degrees that makes less than 2mm change
>in trail.
Assuming the entries in my cyclocomputers are accurate, the
difference in radius is about 1.1 cm.
Whether the difference in handling is caused by the lighter
wheels or their smaller diameter, wide 700c tires will fix both.
Dave Blake
> Whether the difference in handling is caused by the lighter
> wheels or their smaller diameter, wide 700c tires will fix
> both.
Stop being so damned practical - you are interfering with
a debate. :)
I agree entirely - larger slicks are the most likely cure -
preferably wide Avocets.
--
Dave Blake
dbl...@phy.ucsf.edu
Tim McNamara
700C... do I have that right? And then he noticed the bike felt
different riding no-handed: less stable, more squirrely, right?
So now we're in a debate about whether or not the reduction in diameter
has reduced the trail and hence stability of his bike. We have various
calculations about what the difference might be ranging from an ant's
eyebrows to a caterpiller's left hip in magnitude.
I wonder about something else... were those 27 x 1 1/8 (~27 mm) tires
inflated to about 100 psi? And are the new skinnies inflated to about
120 psi? Is the contact patch therefore appreciably smaller, so that
the steering is less damped by the friction of the tire against the
ground? And therefore feels less stable when riding no-handed, since
the contact patch is just about all that's providing any damping?
Just wondering.
Tony Raven
<jobst....@stanfordalumni.org> wrote in message
news:9B6v7.2393$no1....@typhoon.sonic.net...
> I'm interested because I have
> easily ridden a bicycle no-hands without handlebars and stem (no
> weight out front other than the offset of the wheel in the fork).
>
I'm curious. Did they come off in your hands? Otherwise, how did you get
started?
Tony
Ron Hardin
> > The inertial effect turns the wheel right when you cock the frame
> > left. This is what makes steering no-handed possible. It's easiest
> > to see at low speeds, as you say, thus confusing me as to what
> > you're arguing, since you seem to be taking my side.
>
> I'm saying that the effect you observe is not significant at higher
> speeds for the reasons I stated (and you chose not to cite).
I agreed with you, or you agreed with me if you look back. That has an
effect too, increased difficulty in steering (not balancing) because of
loss of countersteer. That's an effect that proves my point, namely that
at low speeds countersteer makes it easy, and its loss makes it hard at
high speeds.
Henrik Münster
> Stunt bicycles have no trail and a vertical steer tube and are ridden
> to great success by experts in the business. If you get the chance
> see the movie "Joe E Brown at the Six Day Races", a must for all
> bikies... a classic.
>
> http://www.hollywood.com/celebs/detail/celeb/199367
>
> Don't miss it!
Tried the URL, but it doesn't give much information. About when
was the film made? Strange site BTW. The birth dates of the persons are
there, but not the date of death. I don't suppose Joe E. Brown is alive
anymore, and the director of the film was born in 1889. Perhaps the
Hollywood spirit is happy and optimistic, so they just forget, that
people do die eventually.
--
Venlig hilsen
Henrik Münster
Esbjerg
jobst....@stanfordalumni.org
>> I'm interested because I have easily ridden a bicycle no-hands
>> without handlebars and stem (no weight out front other than the
>> offset of the wheel in the fork).
> I'm curious. Did they come off in your hands? Otherwise, how did
> you get started?
I was riding with an aluminum expander bolt when it broke while
accelerating standing. The bars were free and swung from side to side
as I sat down and continued essentially no-hands having to hold the
bars pointing forward so that I could operate the brakes. I rode more
than two miles across town to Palo Alto Bicycles where I put in a
steel binder bolt.
Jobst Brandt <jobst....@stanfordalumni.org>
jobst....@stanfordalumni.org
>>> The inertial effect turns the wheel right when you cock the frame
>>> left. This is what makes steering no-handed possible. It's
>>> easiest to see at low speeds, as you say, thus confusing me as to
>>> what you're arguing, since you seem to be taking my side.
>> I'm saying that the effect you observe is not significant at higher
>> speeds for the reasons I stated (and you chose not to cite).
> I agreed with you, or you agreed with me if you look back. That has
> an effect too, increased difficulty in steering (not balancing)
> because of loss of countersteer. That's an effect that proves my
> point, namely that at low speeds countersteer makes it easy, and its
> loss makes it hard at high speeds.
I guess you missed it or don't want to include that in your response
but I find riding no-hands easy at any speed above about 5mph getting
progressively easier up to and over 60mph.
Do you ride no-hands or why do you persist in your perception?
Jobst Brandt <jobst....@stanfordalumni.org>
Ron Hardin
> > I agreed with you, or you agreed with me if you look back. That has
> > an effect too, increased difficulty in steering (not balancing)
> > because of loss of countersteer. That's an effect that proves my
> > point, namely that at low speeds countersteer makes it easy, and its
> > loss makes it hard at high speeds.
>
> I guess you missed it or don't want to include that in your response
> but I find riding no-hands easy at any speed above about 5mph getting
> progressively easier up to and over 60mph.
>
> Do you ride no-hands or why do you persist in your perception?
On the right bike (Raleigh 26" 3-speed) I can ride slowly no-handed and
make right-angle sidewalk turns on regular campus sidewalks. The
trick to be learned is using inertial effects to stabilize the direction
of a front wheel that isn't stable by itself.
Balancing at high speed is easy. Steering is not. Because, as I
said, the countersteer is lacking.
I'd say the easiest speed is about 15mph, where the front wheel
is stable against inertial effects but the inertial effects are
still large enough to produce countersteering.
Perhaps you are unusally skilled at high speeds as I am at low.
Jay W. Beattie
<jobst....@stanfordalumni.org> wrote in message
news:VEmv7.2606$no1....@typhoon.sonic.net...
> Ron Hardin writes:
>
> >>> The inertial effect turns the wheel right when you cock the
frame
> >>> left. This is what makes steering no-handed possible. It's
> >>> easiest to see at low speeds, as you say, thus confusing me as
to
> >>> what you're arguing, since you seem to be taking my side.
>
> >> I'm saying that the effect you observe is not significant at
higher
> >> speeds for the reasons I stated (and you chose not to cite).
>
> > I agreed with you, or you agreed with me if you look back. That
has
> > an effect too, increased difficulty in steering (not balancing)
> > because of loss of countersteer. That's an effect that proves my
> > point, namely that at low speeds countersteer makes it easy, and
its
> > loss makes it hard at high speeds.
>
> I guess you missed it or don't want to include that in your response
> but I find riding no-hands easy at any speed above about 5mph
getting
> progressively easier up to and over 60mph.
60 mph with no hands? Must have been a smooth road. -- Jay Beattie.
nospam
<tim...@bitstream.net> wrote:
>He changed from wider tires to skinnier tires, from 27" wheels to
>700C... do I have that right? And then he noticed the bike felt
>different riding no-handed: less stable, more squirrely, right?
Yes. Thats exactly what I did.
>So now we're in a debate about whether or not the reduction in diameter
>has reduced the trail and hence stability of his bike. We have various
>calculations about what the difference might be ranging from an ant's
>eyebrows to a caterpiller's left hip in magnitude.
>
>I wonder about something else... were those 27 x 1 1/8 (~27 mm) tires
>inflated to about 100 psi? And are the new skinnies inflated to about
>120 psi?
Both were slightly under. Original 27 x 1-1/8s were at about 90 and
new 700C x 22mm are at about 100.
>Is the contact patch therefore appreciably smaller, so that
>the steering is less damped by the friction of the tire against the
>ground? And therefore feels less stable when riding no-handed, since
>the contact patch is just about all that's providing any damping?
I would guess the contact area IS smaller.......
>Just wondering.
When I did the wheel swap, I was looking at trying for a bike weight
improvement, as well as less rolling resistance. I got both. However
comfort (road bumps etc) suffered and no-hands is less stable.
Tim McNamara
>On Thu, 04 Oct 2001 23:36:24 -0500, Tim McNamara
><tim...@bitstream.net> wrote:
>
>>He changed from wider tires to skinnier tires, from 27" wheels to
>>700C... do I have that right? And then he noticed the bike felt
>>different riding no-handed: less stable, more squirrely, right?
>
>Yes. Thats exactly what I did.
>
>>So now we're in a debate about whether or not the reduction in diameter
>>has reduced the trail and hence stability of his bike. We have various
>>calculations about what the difference might be ranging from an ant's
>>eyebrows to a caterpiller's left hip in magnitude.
>>
>>I wonder about something else... were those 27 x 1 1/8 (~27 mm) tires
>>inflated to about 100 psi? And are the new skinnies inflated to about
>>120 psi?
>
>Both were slightly under. Original 27 x 1-1/8s were at about 90 and
>new 700C x 22mm are at about 100.
So the 27s were actually pretty soft, and probably had a pretty large contact patch relatively speaking. The 700s are running a little soft and you might have trouble with pinch flats at those pressures. The contact path will be smaller at 100 psi in the skinnier tire, but not as much as if you were running them at 120 psi.
>>Is the contact patch therefore appreciably smaller, so that
>>the steering is less damped by the friction of the tire against the
>>ground? And therefore feels less stable when riding no-handed, since
>>the contact patch is just about all that's providing any damping?
>
>I would guess the contact area IS smaller.......
>When I did the wheel swap, I was looking at trying for a bike weight
>improvement, as well as less rolling resistance. I got both. However
>comfort (road bumps etc) suffered and no-hands is less stable.
Well, rather than getting all fancy with mathematical equations and an arcane discussion of trail (useful to know about but not very helpful for your problem), I'll recommend- as have others before me- that you try a pair of 700 x 28 tires (I'd recommend Avocets or Rivendell Roll-y Polys for high quality tires, or Continental Sport 1000's for decent but cheaper tires. The latter will cost you about $30 for a pair) and see what you think. Ride comfort will certainly improve and stability ought to improve as well. Good luck!
Van Bagnol
> I changed (and trued) the wheels/tires on my road bike last week, from
> 27 x 1-1/8 to 700 x 22mm. Nothing else have changed. With the new
> thinner wheels, the bike is much harder to ride no hands, harder to
> balance. What happened?
The smaller size of the contact patch may have made the steering of the
bike more sensitive to 'no hands' input.
Simple experiment: Trying riding no-hands (on tires that you _can_ ride
with no hands) with the tire pressure high vs aired down. Geometry,
rotating mass, etc., are essentially unchanged, but tires with lower
pressure will have more 'damping' friction which increases steering
stability. You can also try this with slick tires vs knobbies, if you
have a MTB.
This has been my experience, all the hooey about gyroscopic effects
notwithstanding. (A flamefest between JB and RH -- who'd a thunk it?)
Van
--
Van Bagnol / v a n at wco dot com / c r l at bagnol dot com
...enjoys - Theatre / Windsurfing / Skydiving / Mountain Biking
...feels - "Parang lumalakad ako sa loob ng paniginip"
...thinks - "An Error is Not a Mistake ... Unless You Refuse to Correct It"
Mark Hickey
>In article <3bbc819...@news.pacific.net.sg>, Adrian wrote:
>
>> I changed (and trued) the wheels/tires on my road bike last week, from
>> 27 x 1-1/8 to 700 x 22mm. Nothing else have changed. With the new
>> thinner wheels, the bike is much harder to ride no hands, harder to
>> balance. What happened?
>
>The smaller size of the contact patch may have made the steering of the
>bike more sensitive to 'no hands' input.
>
>Simple experiment: Trying riding no-hands (on tires that you _can_ ride
>with no hands) with the tire pressure high vs aired down. Geometry,
>rotating mass, etc., are essentially unchanged, but tires with lower
>pressure will have more 'damping' friction which increases steering
>stability. You can also try this with slick tires vs knobbies, if you
>have a MTB.
I suspect this may have more to do with the size and shape of the
contact patch than the "damping friction". Virtually all of the
contact patch will always be behind the steering axis, so even though
the trail number won't change (since the center of the CP stays the
same), there will be more self-centering tendency due to the longer,
fatter CP (think of the CP as a rudder hooked to the steer tube).
And, to be truly anal (after all, I'm Sooo good at it), the trail will
actually decrease a tiny bit when you underinflate your front tire,
since it gets "shorter".
Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
>This has been my experience, all the hooey about gyroscopic effects
Aaron Fillion
> with no hands) with the tire pressure high vs aired down. Geometry,
> rotating mass, etc., are essentially unchanged, but tires with lower
> pressure will have more 'damping' friction which increases steering
> stability. You can also try this with slick tires vs knobbies, if you
> have a MTB.
I find that when I ride on knobbies that steering stability does increase, but
this only makes it harder to steer without hands.
When I ride a bike with thinner slicks with higher pressure, the sensitivity
increases and I actually find this easier to control.
With a larger contact patch and increased rolling resistance, I find that the
wheel tends to track straighter. I find this makes the bike harder to control at
slower speeds, because you have to lean harder to steer your wheel.
I have found that the only thing other than tires that effects steering is how
tight the headset is. If the headset is too tight, it will be more difficult to
steer.
If the original poster really wants to know if riding no-hands is more
difficult, he should get an experienced no-handed rider to test both sets of
wheels, then have the test rider render a judgment.
Pierre L
...with all the discussion about tire contact patch, the slight change in in
trail with the new wheel size, the gyroscopic forces, etc., I have to say
that I very much doubt that any of these things would have changed enough to
make any appreciable difference in the ability to ride the bike with no
hands. My suspicion is that these are all red herrings, and that something
else must have changed. Assuming the original poster didn't change his
saddle position or anything else like that, I would put my money on the
newly-built wheels somehow not being quite centered or dished just right, or
some other simple thing that we are all missing.
Also, somewhere in the thread someone mentioned how easy their 3-speed
Raleigh or something was to ride no hands. Well, yes. In the old days, many
bikes would have been easier to ride no hands at slow speed. They were
designed for slow speeds. Most of today's bikes, even mountain bikes and
hybrids, seem harder to ride no hands at slow speeds. The geometry is just
tighter than it is on those old bikes. If all your road bikes are anything
like mine, they are twitchy and nearly impossible to ride no hands at very
slow speeds, but they hunker down and take on a completely different
personnality at higher speeds, just like thoroughbred sports cars.
Pierre
jobst....@stanfordalumni.org
> I suspect this may have more to do with the size and shape of the
> contact patch than the "damping friction". Virtually all of the
> contact patch will always be behind the steering axis, so even
> though the trail number won't change (since the center of the CP
> stays the same), there will be more self-centering tendency due to
> the longer, fatter CP (think of the CP as a rudder hooked to the
> steer tube).
It only affects low speed maneuvering (similar to the effect you feel
riding slowly with low tire pressure, hands on the bars), where
relatively sharp turns are made. At higher speed the effect is
greatly reduced with steering excursions of a degree or so over
greater distance on the road.
> And, to be truly anal (after all, I'm Sooo good at it), the trail
> will actually decrease a tiny bit when you under inflate your front
> tire, since it gets "shorter".
It gets longer, the center of contact trailing the static position.
The introduction of radial tires demonstrated this in cars that had
too little trail with them in contrast to high RR bias ply tires.
Jobst Brandt <jobst....@stanfordalumni.org>
Mark Hickey
>Mark Hickey writes:
>
>> And, to be truly anal (after all, I'm Sooo good at it), the trail
>> will actually decrease a tiny bit when you under inflate your front
>> tire, since it gets "shorter".
>
>It gets longer, the center of contact trailing the static position.
>The introduction of radial tires demonstrated this in cars that had
>too little trail with them in contrast to high RR bias ply tires.
>
>Jobst Brandt <jobst....@stanfordalumni.org>
Sorry - I wasn't clear. I meant the cross-section of the tire gets
shorter when it's underinflated, which reduces trail very slightly.
The effect of that would be insignificant compared to that of the much
larger contact patch, though.
Van Bagnol
Fillion" <afil...@home.com> wrote:
> > Simple experiment: Trying riding no-hands (on tires that you _can_ ride
> > with no hands) with the tire pressure high vs aired down. Geometry,
> > rotating mass, etc., are essentially unchanged, but tires with lower
> > pressure will have more 'damping' friction which increases steering
> > stability. You can also try this with slick tires vs knobbies, if you
> > have a MTB.
>
> I find that when I ride on knobbies that steering stability does
> increase, but this only makes it harder to steer without hands.
>
> When I ride a bike with thinner slicks with higher pressure, the
> sensitivity increases and I actually find this easier to control.
>
> With a larger contact patch and increased rolling resistance, I find
> that the wheel tends to track straighter. I find this makes the bike
> harder to control at slower speeds, because you have to lean harder
> to steer your wheel.
It would depend, I suppose, on the geometry of the bike in question.
Perhaps more sensitivity is making his bike too squirrely to control
hands-free.
One of my bikes, a folder, is impossible to ride hands-free. It's just
too sensitive. My MTB, on the other hand, is no problem. I do notice,
however, when I switch from slicks to knobbies that hands-free handling
is different, and that the speed range at which I can ride comfortably
with no hands changes.
Kiira Triea
: In article <%41w7.213401$j65.51...@news4.rdc1.on.home.com>, "Aaron
: Fillion" <afil...@home.com> wrote:
:> > Simple experiment: Trying riding no-hands (on tires that you _can_ ride
:> > with no hands) with the tire pressure high vs aired down. Geometry,
:> > rotating mass, etc., are essentially unchanged, but tires with lower
:> > pressure will have more 'damping' friction which increases steering
:> > stability. You can also try this with slick tires vs knobbies, if you
:> > have a MTB.
:>
:> I find that when I ride on knobbies that steering stability does
:> increase, but this only makes it harder to steer without hands.
:>
:> When I ride a bike with thinner slicks with higher pressure, the
:> sensitivity increases and I actually find this easier to control.
:>
:> With a larger contact patch and increased rolling resistance, I find
:> that the wheel tends to track straighter. I find this makes the bike
:> harder to control at slower speeds, because you have to lean harder
:> to steer your wheel.
: It would depend, I suppose, on the geometry of the bike in question.
: Perhaps more sensitivity is making his bike too squirrely to control
: hands-free.
You can't really make a statement like too twitchy without
qualifying it in this kind of discussion I think. There is a range of
geometry which works for handling based on the relationship (very
basically) between things like head tube angle, wheel size, rake and
trail - bikes which behave well and which are specialized in a
certain functionality pretty much have to exist within the ranges
of these geometries.
For instance, one of my earlier framesets was very very twitchy, a
track bike with road dropouts,but it was easy to ride with no hands
because the combination of rake and trail allowed it to track
nicely... just very fast. It would snake down the road reacting very
precisely to the inputs it got from my peddling. You can build a bike
with zero trail and find out how it affects rideability - wear a
helmet. :-)
If a bike had too much trail and tended to "wheel flop" then perhaps
deflating the tire really would help the rider ride no hands as it
would slow the front end down and allow some time for control. But a
road bike with a dialed in front end properly built will be easier to
control with a fully inflated tire. No one factor in two-wheel
suspensions can be considerd seperatly from other parameters.
Motorcycle frame innovators are way ahead of bike people. Look at
www.tonyfoale.com for some good discussions and experimental front
ends.
Kiira
Aaron Fillion
> Perhaps more sensitivity is making his bike too squirrely to control
> hands-free.
I was thinking about my cyclocross bike when I switch from 32c knobbies to 23c
slicks.
Van Bagnol
<tr...@eclipse.qis.net> wrote:
> In rec.bicycles.tech Van Bagnol <v...@crl.com.invalid> wrote:
> : In article <%41w7.213401$j65.51...@news4.rdc1.on.home.com>, "Aaron
> : Fillion" <afil...@home.com> wrote:
>
> : It would depend, I suppose, on the geometry of the bike in question.
> : Perhaps more sensitivity is making his bike too squirrely to control
> : hands-free.
>
> You can't really make a statement like too twitchy without
> qualifying it in this kind of discussion I think. There is a range of
> geometry which works for handling based on the relationship (very
> basically) between things like head tube angle, wheel size, rake and
> trail - bikes which behave well and which are specialized in a
> certain functionality pretty much have to exist within the ranges
> of these geometries.
(I believe I did qualify it, at least partially, but that part of my
post had been snipped when you replied.)
My folding bike has a steep HT angle and not much trail. It is extremely
difficult to ride hands-free. While steering is twitchy (overresponsive)
during regular riding, it is overly stable (underresponsive) wrt 'hip
input' for hands-free riding, requiring gross movements that are often
irrecoverable. My MTB, having a more conventional geometry, is much
easier. Decades ago, when I rode a Stingray clone, I recall it being
difficult to ride hands-free. It had a geometry typical of Stingrays,
and granted, I was only in the fourth grade, but it was quite stable
during normal hands-on steering but oversensitive during attempts to
ride without hands. When I 'graduated' to a 10-speed I was pleased to
discover that hands-free riding was not only possible but facile.
Basically I agree with you that geometry et al affects the range at
which hands-free riding is possible. I'd also like to mention gearing.
There are cadences at which the counterforces I produce from pedaling
actually help hands-free riding, and there are higher/lower gears which
actually make it more difficult. This also changes when I transition
from asphalt to grassy surfaces.
(BTW, changing the rolling surface (e.g., asphalt to grass) might be
another example of illustrating how 'contact patch friction' affects
no-hands riding, as the bike geometry is unaffected.)
Tim McNamara
>My folding bike has a steep HT angle and not much trail. It is extremely
>difficult to ride hands-free. While steering is twitchy (overresponsive)
>during regular riding, it is overly stable (underresponsive) wrt 'hip
>input' for hands-free riding, requiring gross movements that are often
>irrecoverable
You don't mention what type of folding bike, but the majority have really small wheels (16-17") and some of the "twitchiness" you refer to is the smaller diameter interacting with road surface irregularities. Smaller wheels are more easily deflected by bumps.
My Birdy folding bike (17" wheels) is unrideable no-handed. It's just as simple as that. None of my full-size bikes have this problem. My track bike, which has the steepest head angle of any of my bikes (75 degrees) , is eminently rideable no-handed on the road.
Matthew Temple
the helpful gyroscopic action of 700C wheels compared with 20" wheels?
Matt
--
=============================================================
Matthew Temple Tel: 617/632-2597
Director, Research Computing Fax: 617/632-4012
Dana-Farber Cancer Institute m...@research.dfci.harvard.edu
44 Binney Street, JF 314 http://research.dfci.harvard.edu
Boston, MA 02115 Choice is the Choice!
Kiira Triea
: In article <yEVw7.10431$GT2.79...@news-read1.qis.net>, Kiira Triea
: <tr...@eclipse.qis.net> wrote:
:> You can't really make a statement like too twitchy without
:> qualifying it in this kind of discussion I think. There is a range of
:> geometry which works for handling based on the relationship (very
:> basically) between things like head tube angle, wheel size, rake and
:> trail - bikes which behave well and which are specialized in a
:> certain functionality pretty much have to exist within the ranges
:> of these geometries.
: (I believe I did qualify it, at least partially, but that part of my
: post had been snipped when you replied.)
: My folding bike has a steep HT angle and not much trail. It is extremely
: difficult to ride hands-free. While steering is twitchy (overresponsive)
: during regular riding, it is overly stable (underresponsive) wrt 'hip
: input' for hands-free riding, requiring gross movements that are often
: irrecoverable. My MTB, having a more conventional geometry, is much
: easier. Decades ago, when I rode a Stingray clone, I recall it being
: difficult to ride hands-free. It had a geometry typical of Stingrays,
: and granted, I was only in the fourth grade, but it was quite stable
: during normal hands-on steering but oversensitive during attempts to
: ride without hands. When I 'graduated' to a 10-speed I was pleased to
: discover that hands-free riding was not only possible but facile.
i'll guess though that the folding bike has a small wheel?
I was thinking of a bike I built with a very responsive geometry that
was very easy to ride no hands. It would snake down the road very
predictably, illustrating how the input from rider forces and
centrifugal precession caused the front wheel to cross over the
centerline with each pedal stroke. But it was very balanced... once I
put another fork on this bike to try and soften the ride a bit and it
lost most of its integrity. Increased rake decreased the trail and the
front end started to hunt.
Kiira
Van Bagnol
<tr...@eclipse.qis.net> wrote:
It has a 16" or 20" wheel, like the Stingray. Smaller wheels tend to
increase the 'curvature' of the force-to-deflection responsiveness, but
primarily the trail is practically nonexistent on the folder due to
large rake and steep head tube angle. This apparently an engineering
constraint to have a small frame yet still provide sufficient top tube
length, and steering clearance. By eyeball, the trail looks pretty much
zero. This is in contrast to my regular bikes and even to my children's
bikes, whose trail is clearly several inches by visual inspection, even
though the wheels are just as small.
Leaning the folder didn't deflect the wheel unless you leaned _quite_ a
lot, at which point you cannot correct the lean. Leaning the kids' bikes
deflect the wheels nominally, as do the regular bikes.
> I was thinking of a bike I built with a very responsive geometry that
> was very easy to ride no hands. It would snake down the road very
> predictably, illustrating how the input from rider forces and
> centrifugal precession caused the front wheel to cross over the
> centerline with each pedal stroke. But it was very balanced... once I
> put another fork on this bike to try and soften the ride a bit and it
> lost most of its integrity. Increased rake decreased the trail and the
> front end started to hunt.
Yep, that would do it!